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12036004 Abbott, Ben W. (University of Alaska Fairbanks, Department of Biology, Fairbanks, AK); Schuur, E. A. and Jones, Jay. Timing and magnitude of CO2 and CH4 release from the permafrost region; an expert elicitation [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41F-02, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Permafrost contains more than twice as much carbon as currently exists in the atmosphere. As temperature increases and permafrost is lost, a portion of this carbon pool will be released as CO2 and CH4, however, the rate and magnitude of this release is highly uncertain. In June of 2011 we administered an expert elicitation survey at the Vulnerability of Permafrost Carbon Research Coordination Network Synthesis Workshop in Seattle. The 43 permafrost, carbon, and climate experts were asked to estimate the magnitude of permafrost degradation and subsequent CO2 and CH4 release in response to four arctic and boreal warming scenarios, adapted from the most recent IPCC radiative forcing scenarios. We asked respondents to quantitatively estimate permafrost loss and net change in permafrost-region soil carbon, as well as to provide a qualitative self-rating of their confidence and relevant expertise concerning each question. Because direct measurements of arctic carbon fluxes are scarce and the quantity and distribution of soil carbon in the arctic is only coarsely characterized, expert elicitation methods allowed us to integrate results from both field and modeling research efforts, and to measure consensus and quantify uncertainty concerning the activation of the pan-arctic permafrost carbon pool. Results indicate rapid permafrost loss and substantial carbon release by the end of the century for even modest warming scenarios--between 56 and 193 Pg of cumulative carbon release by 2100 depending on the magnitude of warming. Under the current warming trajectory, the permafrost region will soon become one of the largest ecosystem sources of green house gases.
12035933 Aleksyutina, D. (Moscow State Univesity, Department of Geocryology, Moscow, Russian Federation) and Motenko, R. Thermal properties for vegetation cover [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0408, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Different samples of undisturbed vegetation cover were studied under laboratory conditions. Samples were collected from New Chara city, north of the Chita region. Vegetation cover in this area is represented by moss, lichen and tussock growth. Thermal properties were investigated by the I-st type regular mode method (a-calorimeter), the freezing temperature was studied by cryoscopic methods. The dry density of sampled specimens varies from 0.04 to 0.24 g/cm3, and humidity varies from 250 to 375 percent. The freezing temperature depends on moisture content and varies from -0.2 to 0 degrees centigrade. The vegetation cover had low thermal conductivities which varies from 0.05 to 0.46 W/(m.K) in unfrozen conditions, and from 0.07 to 1.14 W/(m.K) in frozen conditions, according to density and moisture content. Diffusivity of samples varies from 0.073.10-6 to 0.114.10-6 m2/s in thawed conditions, and from 0.174.10-6 to 0.584.10-6 m2/s in frozen conditions. The sod (bottom of vegetation cover) had relatively high thermal properties. Thermal properties of vegetation cover and peat (turf) were compared. The thermal conductivity of peat was much higher than thermal conductivity of vegetation cover. This data may be used for modeling of the thickness of the seasonally thawed layer and ground temperature variation. The knowledge of thermal properties of these samples allows us to view vegetation cover as a separate layer of geological section.
12035921 Altmann, Garrett (Los Alamos National Laboratory, Department of Earth and Environmental Sciences, Los Alamos, NM); Verbyla, D.; Rowland, J. C.; Yoshikawa, K.; Fox, J.; Chen, Min and Wilson, C. J. Surface water dynamics of shallow lakes following wildfire in Alaska's discontinuous permafrost [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0396, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Wildfire is ubiquitous to boreal Alaska and is the primary disturbance regime affecting thawing permafrost and ecosystem processes in this region. Annually, an average area of 400,000 Ha burns in Alaska (Kasischke et al., 2010) and 96% of these fires occur in the interior portion of the state. Alaska's Interior contains numerous lakes and is widely associated with discontinuous permafrost, which is warmer than 1°C and more prone to thawing than continuous permafrost. Recent studies have indicated regional drying and shrinking of lakes throughout the boreal areas (Riordan et al., 2006; Klein, et al., 2005; Yoshikawa & Hinzman, 2003). While these lake dynamics have been attributed to both changes in climate and subsurface controls, the impact of fire on these changes has not been explored. Fire has a profound effect on the depth of the seasonally thawed active layer. The active layer depth is influenced by the thickness of the organic layer and typically thaws between 0.5 and 2 m from the surface (Bloom, 1998). A severe fire, however, can physically reduce or remove the organic layer and active layer depths have been known to deepen more than 3-4 m after fire disturbance (Yoshikawa et al., 2003). Deepening of the active layer may improve exchanges between surface water and the groundwater system, thus facilitating changes in lake areas as lateral and vertical discharge occurs through patches of unfrozen ground (talik). Because surface and near surface hydrology is strongly affected by the presence of permafrost, changes in active layer thickness and permafrost extent may mark a distinct change of character in surface hydrology (Hinzman, 2005). In this study, we applied remote sensing and GIS to examine lake dynamics following wildfire in four regions of Interior Alaska. Study area selection was based on site association with discontinuous permafrost, lake and pond abundance, previous lake studies, and historical fire incidence between 1950 and 2009. An observation period of 25 years (1984-2009) was selected based upon temporal overlap of historical fire data and the availability of Landsat TM/ETM+ imagery. A total of 24 fire sites and 300 lakes were examined. Lakes in areas disturbed by fire (burn lakes) since 1980 were extracted with a selected sample of control lakes in adjacent non-burned areas. Criteria for selecting control lakes was based on proximity to burn area (<5 km), lake size (<25%), hydrologic similarity (proximity and connectivity with other features), vegetation, and topography. Three post-fire temporal periods were used to assess the lake area response to fire: Short-term (0-5 years); mid-term (5-10 years); and long term (>10 years). Burn severity was assessed around lakes displaying >&eq;25% change by calculating the radiant temperature change in thermal infrared imagery (band 6) for each fire. A regression model was also used to detect the impact of fire between the two study groups. By comparing lakes in burn areas to lakes in control areas, this study aims to capture the effects of fire on shallow lake dynamics in Alaska's interior boreal forest.
12035917 Astley, Beth N. (U. S. Army Cold Regions Research and Engineering Laboratory, Anchorage, AK); Douglas, Thomas A.; Campbell, Seth; Snyder, C.; Goggin, Elise M. and Saari, Stephanie P. Response of permafrost to anthropogenic land surface disturbance near Fairbanks, Alaska [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0392, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Permafrost near Fairbanks Alaska is relatively warm (measured between -1 and 0°C in this study), and is thus highly susceptible to thawing following surface disturbance by land clearing or fire. The surface moss layer and other vegetation are important insulators for near-surface permafrost in the summer months. The removal of this insulation causes the seasonally thawed (active layer) depth to increase and eventually results in formation of taliks (thawed ground below the seasonally frozen active layer). We have been investigating the response of permafrost seasonal thaw depths and rates in soils commonly found around Fairbanks, Alaska following anthropogenic disturbances such as trails, roads, and large clearings. This information is useful to predict the impact of future disturbances on the permafrost landscape and on local ecology and aids in modeling permafrost stability under land that has already been cleared of vegetation. We combined direct current resistivity, ground-penetrating radar (GPR), and borehole data to evaluate permafrost top-down thawing at multiple locations in the Fairbanks area: on Fort Wainwright north of the Chena River, south of the Chena River within Yukon Training Area (YTA), and at the Farmer's Loop Permafrost Research Site. These sites were cleared of vegetation in the past and were selected to represent time since disturbance. The trails north of the Chena River were cleared in 1994 and were surveyed with GPR in 1994-1995, the YTA site was cleared around 1965, and the Farmer's Loop site was cleared in 1946. These sites represent varying types of soil including alluvial soils (containing sandy gravel capped with sandy silt) on Fort Wainwright and thick loess at Farmer's Loop Road. The YTA site does not contain deep borings for detailed stratigraphic interpretation, but hand auguring confirmed this site also contains thick loess at the surface. Resistivity data were used to discern taliks from permafrost and were compared to the 1994-1995 GPR data at the Fort Wainwright site. Resistivity values at the loess sites were in the range of 200-300 ohm-m for "warm" frozen silt and generally over 3,000 ohm-m in frozen alluvium. Permafrost has thawed to depths greater than 9 m in portions of all the sites and patterned ground due to thawed ice wedges can be seen at the YTA site. Thermokarst wetlands are present along trails at the alluvial site and in depressions created by melting of ice wedges at the Yukon Training Area site. The results of this study provide long-term rates of top-down permafrost thaw at sites mechanically cleared of vegetation, relative subsidence measurements compared to surrounding undisturbed land, and examples of landscape change due to vegetation removal.
12035940 Balser, A. (University of Alaska Fairbanks, Department of Biology & Wildlife, Fairbanks, AK); Gens, R. and Jones, Jay. Synthetic aperture RADAR (SAR) polarimetry for detection and monitoring of thermokarst landforms in the Noatak Basin, Brooks Range, Alaska [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41C-0415, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Thermokarst landforms may constitute significant ecological and biogeochemical disturbances at catchment to regional scales, but distribution and periodicity of thermokarst processes are poorly understood in northern Alaska. SAR polarimetry using data from space-borne platforms (RADARSAT-2, PALSAR) can exploit geomorphic and hydrologic properties of thermokarst landforms for possible feature detection, identification of development stage, and monitoring of thermokarst initiation periodicity at broad scales. Results of successful polarimetric analysis better enable modeling of potential future thermokarst process distribution, scaling of thermokarst impact/recovery studies, and may help parameterize global circulation models through quantification of thermokarst-associated carbon release.
12035989 Bartsch, A. (Vienna University of Technology, Institute of Photogrammetry and Remote Sensing, Vienna, Austria); Heim, Birgit; Elger, Kirsten K.; Hayman, G. D. and Trofaier, A. Remote sensing for monitoring of land surface hydrology at high latitudes within the framework of the ESA DUE Permafrost and STSE ALANIS-Methane projects [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41C-0820, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Time series of a wide range of biogeophysical parameters from satellite data are available to date on a global scale. A few initiatives focus on their improvement and validation in high latitudes. For example the DUE Permafrost and STSE ALANIS-Methane, which are activities funded by the European Space Agency, focus on this issue. ALANIS Methane is a research project to produce and use a suite of relevant earth observation (EO) derived information to validate and improve one of the next generation land-surface models and thus reduce current uncertainties in wetland-related CH4 emissions. The task of the ESA DUE Permafrost project is to build up an Earth observation service for high-latitudinal permafrost applications. Results which are shown in this paper contribute to both. Microwave sensors are of special interest in this context due to their independence on cloud conditions and illumination of the Earth Surface. They can be used for derivation of land surface temperature, snow properties and land surface hydrology. The latter includes near surface soil moisture and inundation. Such parameters are of importance for studies on e.g. permafrost and land-atmosphere exchange. Datasets derived from active microwave instruments operating in C-band have been analysed with respect to their usability at high latitudes. Several examples from western Siberia are discussed.
12035927 Becher, Marina (Umea University, Department of Ecology and Environmental Science, Umea, Sweden) and Klaminder, Jonatan. Past activity of non-sorted circles fields in northern Sweden [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0402, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Non-sorted circles (NSCs), also known as frost boils, are common geomorphological features created by cryogenic processes in subarctic and arctic soils [Washburn, 1979]. Near-surface permafrost is thought to be a prerequisite for the activity of NSCs [Walker et al., 2008], where an active NSC maintains a sparsely vegetated circle-like zone in the centre due to frost heave and up-freezing of silt. Little is known about the historical activity of NSCs in northern Scandinavia. Here we summarize some results of our ongoing research where we have assessed historical changes in NSC activity in the Abisko area, northern Sweden. In short, we have estimated how the distribution of NSCs along an altitude gradient has changed from 1959 to 2008 by using digitized aerial photos. Unsupervised classification with two classes (bare mineral soil and shrub vegetation) was performed on NSC fields to achieve estimations on how the aerial coverage of up-frozen mineral soil has changed over the last decades. Here, over growth of previous bare mineral soil surfaces by shrubs was interpreted as decreased NSC activity, considering that vascular plants are unable to colonize active NSCs due to significant heave and disruption of plant roots [Jonasson, 1986]. In addition to observations from aerial photos, we have conducted vertical sampling of NSC soil stratigraphies and 14C-dated buried organic soil layers to constrain the historical activity of the NSC in time. Preliminary analyses of the aerial photos indicate a general overgrowth of bare mineral surfaces within the NSCs since 1959. Of 137 studied sites 92 sites (corresponding to 67%) show an net overgrowth of previous bare mineral soil surface within the circles. On average, about 29% of the bare mineral soil within the NSC fields is estimated to have been colonized by shrub vegetation. Clearly, our findings indicate that permafrost-controlled soil frost activities of the studied NSCs have mainly decreased during the last five decades. The preliminary result of 14C dating (at the time of writing 5) of buried organic layers indicates an onset of NSC activity ~AD 1200. Observations of up-frozen silt deposited on top of podsolized soil in the excavated pits witness that stable soil conditions prevailed prior to the onset of NSC activity. Furthermore, several buried organic layers date back to approximately 1900 AD, indicating a high activity in NSCs at least until this time. Considering that NSC activity is thought to be indicative of permafrost, our results suggest that uphill soils in the study area were affected to a limited extent by cryoturbic processes until the end of the Medieval Warm Period ~AD 1200. Permafrost has likely been present in the soils above tree-line at least until around AD 1900. After AD 1900 the permafrost has likely disappeared from most of the NSC sites, lowering the activity of the NSCs. A finding supported by the plant overgrowth of the NSC fields since 1959 seen in the aerial photos.
12035978 Bhattacharyya, S. (Lawrence Livermore National Laboratory, Atmosphere, Earth and Energy Division, Livermore, CA); Cameron-Smith, P. J.; Bergmann, D.; Reagan, M. T.; Collins, W.; Elliott, S. M. and Maltrud, M. E. Atmospheric impact of large methane emission in the Arctic region [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41B-0803, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
A highly potent greenhouse gas, methane, is locked in the solid phase as ice-like deposits containing a mixture of water and gas (mostly methane) called clathrates, in ocean sediments and underneath permafrost regions. Clathrates are stable under high pressure and low temperatures. Recent estimates suggest that about 1600-2000 GtC of clathrates are present in oceans and 400 GtC in Arctic permafrost (Archer et al.2009) which is about 4000 times that of current annual emissions. In a warming climate, increase in ocean temperatures could alter the geothermal gradient, which in turn could lead to dissociation of the clathrates and release of methane into the ocean and subsequently into the atmosphere as well. This could be of particular importance in the shallow part of the Arctic Ocean where the clathrates are found in depths of only 300 m. In this presentation, we shall show results from our ongoing simulation of a scenario of large scale methane outgassing from clathrate dissociation due to warming ocean temperatures in the Arctic based on ocean sediment modeling. To that end we use the CESM (Community Earth System Model) version 1 with fully active coupled atmosphere-ocean-land model together with fast atmospheric chemistry module to simulate the response to increasing methane emissions in the Barents Sea, Canadian Archipelago and the Sea of Okhotsk. The simulation shows the effect these methane emissions could have on global surface methane, surface ozone, surface air temperature and other related indices.
12035992 Bohn, T. J. (University of Washington, Civil & Environmental Engineering, Seattle, WA); Schroeder, Ronny; Podest, Erika; McDonald, K. C.; Maksyutov, Shamil and Lettenmaier, Dennis P. Assimilation of tower and satellite-based observations for improved estimation of methane fluxes over northern Eurasia [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41C-0825, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Changes in greenhouse gas emissions such as methane and carbon dioxide from high-latitude wetlands in a warming climate have important implications for global warming, due to the large amounts of carbon stored in high-latitude soils and the high greenhouse warming potential of methane. As much as 1/3 of global natural methane emissions come from high latitudes. Efforts to monitor high-latitude greenhouse gas emissions are hampered by the sparseness of in situ observations at high latitudes, especially in Northern Eurasia. One promising approach is to assimilate spatially sparse tower- and satellite-based observations into large-scale process-based models. In addition, because methane fluxes are sensitive to hydrologic variables such as inundation, passive microwave satellite observations of surface water can also be assimilated. Here we apply an ensemble Kalman smoother to assimilate in situ and satellite observations into our modeling framework, which consists of the Variable Infiltration Capacity (VIC) model, extended to include carbon cycling and coupled to a methane emissions model. This framework is, in turn, coupled to the atmospheric tracer model of Japan's National Institute for Environmental Studies (NIES) to estimate methane concentrations over the West Siberian Lowlands. Observations assimilated include methane concentrations at towers operated by NIES, total column methane concentrations observed by the JAXA GOSAT satellite, and the surface water product of NASA's Jet Propulsion Laboratory derived from AMSR-E and QuickScat observations. We compare the performance of assimilations using these different types of observations and explore how these observations constrain model parameters such as soil moisture content, water table depth distribution, and soil carbon content.
12035910 Boike, J. (Alfred Wegener Institute, Periglacial Research, Potsdam, Germany); Langer, M.; Abnizova, Anna; Fröb, K.; Grüber, Maren; Muster, Sina; Piel, Konstanze; Wischnewski, Karoline; Westermann, S. and Roth, Kurt. Sensitivity of permafrost in the Arctic; a multiscale perspective [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0385, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Permafrost regions occupy approximately 24% of the Northern Hemisphere's land area; these regions are anticipated to be considerably reduced by climate change. Comprehensive data sets are sparse for the Arctic, yet they are of great value to support modeling efforts on current and future arctic climate and permafrost conditions. The SPARC (Sensitivity of Permafrost in the ARCtic) research group concentrates on examining heat, water and carbon fluxes in the Arctic permafrost system at sites in Siberia, Svalbard and the Canadian Arctic and how these processes vary across multiple spatial and temporal scales. Specifically, our goals are to: (i) quantify water and energy fluxes across a spectrum of scales, (ii) identify environmental factors and processes controlling the fluxes, and (iii) understand the interactions with biochemical processes determining the carbon balance of large Arctic areas. This poster summarizes the recent results of the following topics: land cover characteristics, surface temperature and energy balance. The surface energy budget is the key to process understanding in permafrost areas, since it determines the surface temperature and thus the seasonal thawing of the soil. The land surface temperature is related to all components of the energy balance and is thus a crucial parameter when monitoring the energy budget of permafrost environments. Land cover affects the biogeophysical properties of the surface like surface hydrology, albedo, and biomass which determine the exchange of energy, water and carbon fluxes between the surface and the atmosphere. Our results show that especially small ponds and lakes play a dominant role in the water and energy budget of Arctic permafrost landscapes. This is of particular importance, as such land cover heterogeneities are usually not accounted for in large-scale climate models. Hence, model derived estimates of surface temperature, ground heat flux, evaporation as well as carbon fluxes might be biased.
12035948 Bosch, F. P. (RWTH Aachen University, Department of Applied Geophysics, Aachen, Germany); Jorand, R. and Ulmen, Max. NMR study of porosity and permeability variations in artificial, unconsolidated sediment samples during thawing [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41C-0423, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Porosity and permeability of unconsolidated sediments may vary or even change irreversibly during freezing and thawing. These effects are of interest both in permafrost research and with regard to appropriate methods for the preserving of soil or rock samples. We studied variations in porosity and permeability of typical unconsolidated sediment types induced by freezing and thawing. In a first step, we manufactured artificial specimens (saturated with distilled water to 100%) from different materials: a) quartz grains, b) carbonate powder, c) kaolin powder, and d) bentonite powder. Then we recorded T1-and T2-relaxation times using a laboratory NMR Halbach-device for inferring permeability and porosity of the samples prior to freezing at -18°C and during thawing. The same procedure was used on a comparable volume of pure water in order to isolate the effect of the ratio of liquid water to ice. Additionally, we studied the variations of decay time amplitudes with temperature above 0°C. We present the effect on NMR relaxation times due to freezing and thawing of samples and its interpretation with regard to the ratios of liquid water to ice and free to bound water, changes in pore size distribution, and, generally, porosity and permeability.
12035924 Bouchard, Frederic (Institut National de la Recherche Scientifique, Quebec City, QC, Canada); Francus, P. and Pienitz, Reinhard. Recent dynamics of thermokarst ponds in discontinuous permafrost; a paleolimnological study from subarctic Quebec, Canada [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0399, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Accelerated thawing and erosion of permafrost is leading to the release of organic carbon through greenhouse gas emissions, especially in thermokarst (thaw) ponds and lakes. These aquatic ecosystems are widespread throughout arctic and subarctic regions; however their natural variability and temporal evolution recorded in the bottom sediments are poorly understood. Here we present a multi-proxy study conducted in a subarctic site with many thermokarst ponds near Kuujjuarapik-Whapmagoostui, on the eastern shore of Hudson Bay, at the southern edge of the discontinuous and scattered permafrost zone. Sedimentological, geochemical and biological (diatoms) analyses have been performed on short sediment cores (10-20 cm) retrieved from limnologically contrasted ponds. Long-term (14C) and short-term (210Pb, 137Cs) chronologies were also established. Analyses revealed two distinct sedimentary facies, from bottom to top: 1) massive marine silts and clays deposited during postglacial Tyrrell Sea transgression (ca. 8000 to 6000 cal yr BP), subsequently emerged by glacio-isostatic rebound and more recently (ca. 1500 to 400 cal yr BP) affected by permafrost inception and growth; 2) laminated organic-rich lacustrine muds deposited since permafrost thawing and subsidence, i.e. since thermokarst pond inception (the last centuries). Almost absent from the bottom sediments (lower facies), benthic and planktonic diatoms appeared highly abundant in surface lacustrine sediments (upper facies) and reflected past changes in bottom water properties (e.g., pH, dissolved organic carbon, water color). Despite displaying strikingly different water colors, the study ponds showed similar long-term developmental patterns regarding their biogeochemical properties (as recorded in the sediments), such as: decreasing mineral grain size (from silts to clays); decreasing major chemical element concentrations; increasing organic matter content and decreasing pH (establishment of peatland vegetation/soils); decreasing bottom water oxygen concentrations (from well-oxygenated to anoxic/hypoxic conditions). Contributing to a growing literature on thermokarst pond evolution at northern latitudes, this study provides the litho/bio-stratigraphic background on which present-day conditions (e.g., geomorphology, biology, optical properties) can be interpreted.
12035931 Bradley-Cook, Julia I. (Dartmouth College, Department of Biological Sciences, Hanover, NH); Burzynski, Amy; Hammond, Courtney R. and Virginia, Ross A. Land cover heterogeneity and soil respiration in a West Greenland tundra landscape [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0406, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Multiple direct and indirect pathways underlie the association between land cover classification, temperature and soil respiration. Temperature is a main control of the biological processes that constitute soil respiration, yet the effect of changing atmospheric temperatures on soil carbon flux is unresolved. This study examines associations amongst land cover, soil carbon characteristics, soil respiration, and temperature in an Arctic tundra landscape in western Greenland. We used a 1.34 meter resolution multi-spectral WorldView2 satellite image to conduct an unsupervised multi-staged ISODATA classification to characterize land cover heterogeneity. The four band image was taken on July 10th, 2010, and captures an 18 km by 15 km area in the vicinity of Kangerlussuaq. The four major terrestrial land cover classes identified were: shrub-dominated, graminoid-dominated, mixed vegetation, and bare soil. The bare soil class was comprised of patches where surface soil has been deflated by wind and ridge-top fellfield. We hypothesize that soil respiration and soil carbon storage are associated with land cover classification and temperature. We set up a hierarchical field sampling design to directly observe spatial variation between and within land cover classes along a 20 km temperature gradient extending west from Russell Glacier on the margin of the Greenland Ice Sheet. We used the land cover classification map and ground verification to select nine sites, each containing patches of the four land cover classes. Within each patch we collected soil samples from a 50 cm pit, quantified vegetation, measured active layer depth and determined landscape characteristics. From a subset of field sites we collected additional 10 cm surface soil samples to estimate soil heterogeneity within patches and measured soil respiration using a LiCor 8100 Infrared Gas Analyzer. Soil respiration rates varied with land cover classes, with values ranging from 0.2 mg C/m2/hr in the bare soil class to over 5 mg C/m2/hr in the graminoid-dominated class. These findings suggest that shifts in land cover vegetation types, especially soil and vegetation loss (e.g. from wind deflation), can alter landscape soil respiration. We relate soil respiration measurements to soil, vegetation, and permafrost characteristics to understand how ecosystem properties and processes vary at the landscape scale. A long-term goal of this research is to develop a spatially explicit model of soil organic matter, soil respiration, and temperature sensitivity of soil carbon dynamics for a western Greenland permafrost tundra ecosystems.
2035932 Cable, J. (University of Alaska Fairbanks, Fairbanks, AK); Ogle, Kiona and Welker, J. M. Transpiration response of boreal forest plants to permafrost thaw [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0407, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Shifts in the rate and patterns of evapotranspiration with permafrost thaw, vegetation change, and altered climatic conditions are unknown in boreal systems. Specifically, the response of transpiration is not well understood but critical to quantify given its non-linear response to climate. We asked: what is the effect of permafrost thaw on the transpiration dynamics of sub-Arctic boreal plants? We utilized a Bayesian analysis approach to quantify the responses of plants located in areas with and without stable permafrost to current and antecedent vapor pressure deficit, soil moisture, soil temperature, and the prior year's soil temperature. We measured stomatal conductance (gs) on six species of plants over two summers. For the analysis, the plants were grouped into three functional types: deciduous shrubs, evergreen sub-shrubs, and black spruce trees. The model we constructed includes a VPD (current and antecedent) sensitivity term modeled as a function of soil moisture (current and antecedent), and a "base" gs term modeled as a function of current soil temperature (at different depths), thaw depth, and the prior growing season's soil temperature (for each month, May-September). Current VPD was more important early in the growing season, but antecedent VPD was more important later in the growing season. The memory of gs for antecedent VPD was ~three weeks in the past. The daily trends were less resolved for the site with degrading permafrost. Deeper thaw resulted in higher sensitivity to VPD and higher gs, particularly at the site with stable permafrost. Deciduous shrubs showed the strongest effect. At the site with thawing permafrost, soil water positively affected the sensitivity of gs to VPD for the deciduous shrubs but had a negative effect on black spruce. Current soil moisture was important early in the growing season but antecedent moisture was important at the end. The site with thawing permafrost had a longer memory (two weeks) for antecedent moisture than the site with stable permafrost. In terms of the "base" gs rate, current soil temperature positively affects gs in the deciduous functional types. The prior year's soil temperature positively affected the black spruce base rate at the end of the season, but negatively affected the evergreen sub-shrubs at the beginning of the season. Soil temperature the prior year's May was most important at the site with thawing permafrost, but May and June were important for the site with stable permafrost. These preliminary results suggest that (1) we must account for within-season and the prior year's antecedent conditions when quantifying the effects of permafrost thaw on plant function, and (2) permafrost thaw changes how boreal forest plant species respond to climate and soil conditions. Next, we must quantify the mechanisms of the antecedent response to determine thresholds in thaw that could result in shifts in species composition.
12035944 Carbonneau, Andrée (Université Laval, Department of Geography, Quebec City, QC, Canada); Allard, Michel; L'Hérault, Emmanuel and LeBlanc, Anne-Marie. High permafrost ice contents in Holocene slope deposits as observed from shallow geophysics and a coring program in Pangnirtung, Nunavut, Canada [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41C-0419, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
A study of permafrost conditions was undertaken in the Hamlet of Pangnirtung, Nunavut, by the Geological Survey of Canada (GSC) and Universite Laval's Centre d'Etudes Nordiques (CEN) to support decision makers in their community planning work. The methods used for this project were based on geophysical and geomorphological approaches, including permafrost cores drilled in surficial deposits and ground penetrating radar surveys using a GPR Pulse EKKO 100 extending to the complete community area and to its projected expansion sector. Laboratory analysis allowed a detailed characterization of permafrost in terms of water contents, salinity and grain size. Cryostratigraphic analysis was done via CT-Scan imagery of frozen cores using medical imaging softwares such as Osiris. This non destructive method allows a 3D imaging of the entire core in order to locate the amount of the excess ice, determine the volumetric ice content and also interpret the ice-formation processes that took place during freezing of the permafrost. Our new map of the permafrost conditions in Pangnirtung illustrates that the dominant mapping unit consist of ice-rich colluvial deposits. Aggradationnal ice formed syngenitically with slope sedimentation. Buried soils were found imbedded in this colluvial layer and demonstrates that colluviation associated with overland-flow during snowmelt occurred almost continuously since 7080 cal. BP. In the eastern sector of town, the 1 to 4 meters thick colluviums cover till and a network of ice wedges that were revealed as spaced hyperbolic reflectors on GPR profiles. The colluviums also cover ice-rich marine silt and bedrock in the western sector of the hamlet; marine shells found in a permafrost core yielded a radiocarbon date of 9553 cal. BP which provides a revised age for the local deglaciation and also a revised marine submergence limit. Among the applied methods, shallow drilling in coarse grained permafrost, core recovery and CT-Scan allowed the discovery of the importance of Holocene slope processes on shaping the surface of the terrain and leading to the observed cryostructures and ice contents in the near surface permafrost.
12036005 Chanton, J. (Florida State University, Department of Earth, Ocean and Atmospheric Science, Tallahassee, FL); Crill, Patrick M.; Rich, V.; McCalley, C. K.; Hodgkins, Suzanne B.; Tyson, G.; Logan, T.; Wehr, R.; Mondav, R.; Li, Changsheng; Frolking, Steve and Saleska, S. R. ISOGENIE; linking geochemistry, isotopic chemistry and microbial dynamics & community composition in a thawing permafrost peatland, Stordalen Mire, Abisco, Sweden [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41F-03, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
As permafrost thaws, increasing CH4 emissions from northern wetlands are likely to cause positive feedback to atmospheric warming. One of the over-arching goals of this project is to connect geochemical processes, particularly focusing on methane production, to underlying microbial population dynamics and genomics. Recent transformative technical advances in both high throughput investigations of microbial communities and high temporal resolution biogeochemical isotope measurements now permit a uniquely comprehensive approach to opening the microbial "black boxes" that impact carbon cycling on global scales. This project links detailed microbial sampling with detailed geochemical and isotopic sampling on seasonal and diel timescales and has an extensive modeling component. Gas exchange is monitored across the wetland gradients in a series of automated chambers and isotopes of emitted and belowground methane and carbon dioxide are measured with a QC laser system. The mire is in a state of partial thaw. With this thaw is an apparent ecological session in wetland community structure and associated changes in organic matter lability, rates of methane production and microbial community. Our group's study sites range from palsa with underlying permanently frozen peat, to recently collapsed and flooded palsa, to flooded palsa colonized by Sphagnum, to flooded eriophorum sites, to sites populated by Carex, to open water lakes. Across this environmental gradient pH ranges from 4 to 6.5. This change is driven by changes in hydrology as the surface of the thawing permafrost subsides and an adjacent lake drains into the mire. Along this environmental gradient, from palsa to Carex, the lability of the peat increases significantly as determined in incubations of peat material and monitoring of methane and carbon dioxide production rates. Coincident with this environmental gradient is a decrease in the apparent fractionation factor between methane and carbon dioxide and methane isotopic composition becomes more 13C enriched, due to increased methane production via the acetate pathway.
12035982 Chuvilin, E. M. (Moscow State University, Department of Geology, Moscow, Russian Federation); Buhanov, B. A.; Guryeva, O. M.; Istomin, V. A.; Takeya, S. and Hachikubo, A. Experimental study of metastability of gas hydrate in frozen sediments [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41B-0807, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
The stability zone of natural gas hydrates formations in cryolithozone where methane gas hydrates can be formed and exist, begins with depths of 200-250 meters and extends in sub-permafrost layers up to depths of 800-1500 meters. Recently obtained data allow to consider methane gas hydrates existence in thicknesses of frozen sediments above zone of its thermodynamic stability (up to depths of 200-250 meters) This zone may be called the zone of gas hydrate's metastability or zone of "relict hydrate" existence. The relict natural gas hydrate accumulations in permafrost may have formed under favorable thermodynamic conditions during glacial periods. Subsequently, glacial retreat induced metastable hydrate preservation due to self-preservation effect. At present the existence of natural gas hydrates at shallow depth at nonequilibrium conditions leads to a serious geological hazard during exploration drilling. The dissociation of shallow metastable methane hydrate may contribute to global warming by adding significant amount of a greenhouse gas (methane) to the atmosphere. Up to now relict natural gas hydrates are poorly understood, so the experimental research of gas hydrates decomposition in frozen sediments under non-equilibrium conditions is of significant importance. The experimental technique included the following stages: i) artificial saturation of sediments by methane or carbon dioxide hydrates, ii) freezing of the hydrate-containing samples, iii) studying of the hydrate decomposition process including self-preservation in frozen samples after the reducing gas pressure below line of three phase equilibrium (gaseous phase-gas hydrate-ice). Core samples of different composition and porous structure recovered from gas-showing horizons of permafrost sediments were used. Experimental data on the influence of temperature, pressure, hydrate- and ice-saturation on the kinetics of methane gas hydrates dissociation in natural sediments from permafrost zone was obtained. The experiments show that self-preservation of gas hydrates in frozen sediments is enhanced by low temperatures, high ice content, and low sediment gas permeability. Residual (preserved) hydrate saturation of frozen samples after pressure release below equilibrium reached 20-25%. Experimental researches on kinetics of gas hydrate dissociation in frozen sediments samples selected from gas showing horizons in permafrost confirm the opportunity of long preservation of pore methane gas hydrate in frozen sediments at negative temperatures and pressures below equilibrium due to self-preservation effect. Relic gas hydrates could be source of significant methane emission from shallow permafrost at rise of temperature and thawing.
12035937 de Grandpré, I. (Université de Montréal, Département de Géographie, Montréal, QC, Canada); Fortier, Daniel and Stephani, E. Degradation of ground ice in a changing climate; the potential impact of groundwater flow [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41C-0412, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Climate changes affecting the North West portion of Canada alter the thermal state of the permafrost and promote ground ice degradation. Melting of ground ice leads to greater water flow into the ground and to significant hydraulic changes (i.e. drainage of peatland and lakes, triggering of thermokarst and new groundwater flow patterns). Road infrastructures built on permafrost are particularly sensitive to permafrost degradation. Road construction and maintenance induce heat flux into the ground by the increase of solar radiation absorption (comparing to natural ground), the increase of snow cover on side slopes, the infiltration of water in embankment material and the migration of surface water in the active layer. The permafrost under the roads is therefore submitted to a warmer environment than in natural ground and his behavior reflects how the permafrost will act in the future with the global warming trend. The permafrost degradation dynamic under a road was studied at the Beaver Creek (Yukon) experimental site located on the Alaska Highway. Permafrost was characterized as near-zero Celcius and highly susceptible to differential thaw-settlement due to the ground ice spatial distribution. Ice-rich cryostructures typical of syngenetic permafrost (e.g. microlenticular) were abundant in the upper and lower cryostratigraphic units of fine-grained soils (Units 1, 2A, and 2C). The middle ice-poor silt layer (Unit 2B) characterized by porous cryostructure comprised the top of a buried ice-wedge network extending several meters in the underlying layers and susceptible to degradation by thermo-erosion. These particular features of the permafrost at the study site facilitated the formation of taliks (unfrozen zones) under the road which leaded to a greater water flow. We believe that water flow is promoting an acceleration of permafrost degradation by advective heat transfer. This process remains poorly studied and quantified in permafrost environment. Field data on topography, soil geotechnical properties, water table and preferential flow paths characterization, ground and water temperature and active layer and permafrost depth were collected to built seepage, heat transfer and coupled advecto-conductive models. Results indicated that advective heat transfer processes associated with groundwater flow can have a substantial impact on permafrost degradation. After one year, the active layer was 4 m deeper in the advecto-conductive heat transfer model than in the conductive heat transfer model and this was corroborated with measured field data. Groundwater flow processes should therefore be taken into account in permafrost evolution models and climate warming scenarios.
12035981 Disenhof, C. R. (U. S. Department of Energy, National Energy Technology Laboratory, Albany, OR); Rose, Kelly; Wooller, M.; Pohlman, J. and Littlefield, Kyle V. Role of lithology in methane flux from an Alaskan thermokarst lake [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41B-0806, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Thermokarst lakes are prevalent forms on the Alaska North Slope (ANS) that can emit significant quantities of the greenhouse gas methane to the atmosphere. These lakes form in permafrost regions and grow as the water amplifies subsurface heating and causes further degradation of the permafrost. Areas of thawed ground (thaw-bulbs, or taliks) can develop beneath them. When a talik intersects fractures or permeable zones linked to free-gas accumulations, coal beds, or permafrost-associated gas hydrate, methane can be released from the lake. In 2009, a four-core transect extending from an active gas seep in Qalluuraq Lake (Lake Q), an Alaskan thermokarst lake, was taken for lithological analysis to complement paleoecological and biogeochemical studies investigating the current and historical flux of methane from this lake. As part of this study, we completed sedimentological analyses to constrain the lithology of the system and evaluate potential near-lake floor geologic controls on methane seepage at this site. Visual descriptions were completed for each core. Grain size, x-ray diffraction (XRD), petrographic, elemental (C and N) and accelerator mass spectrometer (AMS) radiocarbon analyses were also conducted on subsamples from the cores. The major lithology of all four cores is a quartz-rich, chert-bearing, medium-grained sand. Organic material, including grasses, seed pods, and reworked coal fragments, was observed in some intervals as laminae or as dispersed material. XRD and petrographic analyses indicate quartz is the dominant mineral in every core, though some of the AMS dates on organic laminae in the cores fit with paleoecological reconstructions from the site relating to wetland succession. Though the modern Lake Q is a lacustrine environment, likely formed via thermokarst processes, its underlying sediment is fluvially reworked marine sand. Our analyses indicate that these sediments are part of the Gubik Formation, a Quaternary age sedimentary formation blanketing much of the ANS and representing a variety of depositional environments, including nearshore marine, fluvial, lacustrine, eolian, thermokarst, and glacial. Methane ebullition, resulting from wetlands initiation ~12,000 cal yr BP, appears to have winnowed fine-grained organic material from the active seep sediments. The resulting coarse-grained and moderately well-sorted seep sediments are an unrestricted conduit that facilitates the gas and fluid flux to the lake and atmosphere.
12035918 Douglas, Thomas A. (U. S. Army Cold Regions Research and Engineering Laboratory, Fairbanks, AK); Liljedahl, A. K.; Astley, Beth N.; Downer, Charles W.; Jorgenson, T. T.; Bagley, Calvin and Burks-Copes, Kelly A,. Anticipated impacts of climate warming on ecosystems in interior Alaska [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0393, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Future climate scenarios predict a roughly 5 degree increase in mean annual air temperatures for the Alaskan Interior over the next 80 years. This is expected to be enough to initiate permafrost degradation in Interior Alaska which could lead to widespread thermokarst and talik development and potentially a thicker seasonally thawed (active) layer. These changes could dramatically affect hydrology, ground surface topography and vegetation. Forecasting ecological responses to climate warming is complicated by many factors including variations in soil type, precipitation, surface and ground water hydrology, vegetation, slope, aspect, fire prevalence, and the thermal state of permafrost. We are making field measurements and time series repeat imagery at upland and lowland landscapes to determine where and what ecosystem processes may be most susceptible for rapid or unpredictable changes with climate warming or changing land use activities. By integrating existing cryospheric (permafrost and snow), hydrologic and vegetation succession modeling capabilities we hope to enhance our ability to predict how climate change and other stressors may affect ecosystem dynamics and fire susceptibility. We will include the effects of non-climate related anthropogenic stressors like changes in land use activities and infrastructure development. Numerous electrical resistivity geophysical measurements have been made across a variety of landscapes to investigate how vegetation, soils, and land use relates to permafrost distribution. Our project results will be synthesized into a spatially-explicit decision support system to assist with land use management decision-making for Interior Alaska. This Geographic Information Systems (GIS)-based tool is being developed through a combination of field work and modeling. We will identify challenges for management activities given the projected ecosystem response to anticipated climate change by the end-of-the century. This presentation will summarize the first year of research results from this multi-agency, multidisciplinary research project. The project team includes more than 20 researchers, collaborators, students and land users that are actively working on this research program. Results will include geophysical measurements of surface soils and permafrost, the first hydrologic measurements across the Tanana Flats lowlands and the glacier fed Jarvis Creek, repeat imagery of landscapes exhibiting change over time, vegetation mapping, and hydrologic and ecosystem simulations.
12035950 Duguay, C. R. (University of Waterloo, Interdisciplinary Centre on Climate Change, Waterloo, ON, Canada); Soliman, A. S. and Macrae, M. L. Thermal regime of shallow water bodies in the coastal tundra zone of the Hudson Bay Lowlands [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41C-0425, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Many shallow lakes and ponds of the Arctic/sub-Arctic contain thick, organic-rich sediments, which have the potential to release significant amounts of CO2 or CH4 to the atmosphere if sediment decomposition rates increase in response to warmer temperatures caused by global warming. This may be exacerbated by a deepening of the seasonal sediment thaw depth in small water bodies that are underlain by permafrost. An important step in linking climatic conditions to rates of organic matter decomposition and gas production from shallow water bodies is an improved understanding of the thermal properties of lake sediments and how sediment temperatures fluctuate in response to changing air temperatures. This knowledge is also important if the ratio of terrestrial to aquatic landscape units in cold regions changes under a warmer climate. One approach that has been used in terrestrial permafrost environments is the examination of how mean annual permafrost surface temperature deviates from mean annual 2-m screen height air temperature (MAAT). The offset between MAAT and the mean annual sediment surface temperature (MASST) has been found to be much larger in deep aquatic systems (greater than 10 m) than in terrestrial permafrost systems due to the presence of the water column that can efficiently transfer heat through mixing. However, the efficiency of heat transfer in shallow water bodies is expected to larger in summer (thawed) than in winter (frozen) conditions, when thermal energy must move by conduction alone. The present study examined the efficiency of sediment heat transfer in shallow water bodies (less than 3 m) during summer and winter periods. Air, sediment and water temperatures of three shallow water bodies in the coastal tundra zone of the Hudson Bay Lowlands near Churchill, Manitoba, Canada were monitored (December 2009-August 2011). Arrays of thermistors and heat pulse probes were placed at 10 cm increments between 20 cm above the water/sediment interface and 40 cm depth in sediments. Mean hourly rates of temperature change (dT) over each year were grouped into four categories: a) frozen warming trend (FW), b) frozen cooling trend (FC), c) thawed warming trend (TW) and d) thawed cooling trend (TC). MASST were found to be warmer than MAAT by 7-8.5 C, which is above the reported thermal offset range of terrestrial permafrost (usually 3-7 C). Mean dT was similar under FC and FW trends. However, under thawed conditions, mean dT was larger under TW than TC trends (particularly in the open water where both mixing and radiant energy transfer occur). The ratios dTTW/dTFW and dTTC/dTFC were circa 0.5 for sediments below 30 cm, 5-9 for shallow sediments and 9-13 for water, indicating that heat transfer is more efficient for deep sediments under frozen conditions whereas shallow sediments and lake water transfer heat more efficiently under thawed conditions. Conventional thermal offset models for terrestrial permafrost should be modified for coastal environments given the widespread presence of shallow lakes and ponds, and the fact that their presence may change under a warmer climate. Our work has also demonstrated that assigning simple thermal properties for the entire sediment active layer is insufficient.
12035916 Duguay, Max A. (University of Ottawa, Department of Geography, Ottawa, ON, Canada); Lewkowicz, A. G. and Smith, Sharon. Permafrost changes along the Alaska Highway corridor, southern Yukon; from ground temperature measurements and DC electrical resistivity tomography [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0391, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
A natural gas pipeline running across permafrost terrain from Prudhoe Bay, Alaska, through Canada to US markets was first proposed more than 30 years ago. In the intervening period, mean annual air temperatures in the region have risen by 0.5-1.0°C and it is probable that the ground has also warmed. Renewed interest in the pipeline has meant that information on permafrost and geotechnical conditions within the Alaska Highway Corridor of the southern Yukon must be updated for engineering design and the assessment of environmental impacts. To accomplish this goal, results from 1977-1981 drilling and ground temperature monitoring programs within the proposed pipeline corridor were used in combination with air photo analysis to select sites potentially sensitive to climate change. The sites are distributed across the extensive and sporadic discontinuous permafrost zones over a distance of 475 km between Beaver Creek and Whitehorse. To date, 11 targeted boreholes with permafrost have been found and cased to permit renewed ground temperature monitoring. By the end of summer 2011, it is expected that another 7 will have been instrumented. Measurable temperature increases relative to the 1970s are expected, except where values were previously just below 0°C. In the latter case, if the sites are still in permafrost, latent heat effects may have substantially moderated the temperature increase. Electrical resistivity tomography surveys are also being conducted to characterize the local permafrost distribution and geotechnical conditions. These 2D resistivity profiles will be used with the ground temperatures to examine current conditions and response to climate change and vegetation disturbance.
12035970 Etzelmuller, Bernd (University of Oslo, Oslo, Norway); Hipp, Tobias Florian; Schuler, T.; Farbrot, Herman; Isaksen, Ketil; Westermann, Sebastian and Christiansen, Hanne H. Modeling past and future permafrost evolution in northern Europe [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41B-0795, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Since 2003 numerous shallow boreholes were equipped to monitor ground temperatures in northern Europe, especially in Norway, Svalbard and Iceland. The total number of monitored boreholes is 42, of which 4 are located in Iceland, 10 in southern Norway, 16 in northern Norway and 12 in Svalbard. The monitoring stations are setup to characterize the ground thermal regime in different topographic and environmental settings , and to validate spatially distributed, equilibrium and transient permafrost models. Altogether 29 of these monitoring stations have been used to calibrate a transient heat flow model. Forced by Holocene and instrumental historic time series for the past and down-scaled projections of climate scenarios, this model was applied over different time periods: (1) the Holocene time period with 250 y time steps superimposed with annual variations, (2) the instrumental time period since c. 1870 until today with monthly and daily time steps and (3) future scenarios until 2100 with monthly time steps based on downscaled temperature data from GCMs. The results illustrate the possible evolution of permafrost and its response to climate perturbations in sub-arctic mountain and high-arctic environments. In this study, we present the modeled ground temperature and active layer thickness (ALT) development since the end of the Little Ice Age, their possible future evolution and estimates of permafrost ages, especially in the mountain environments of Norway and Iceland. The analysis reveal sharp increases in ALT since the 1990s in all areas, whereas the responses to climate perturbations since the end of the Little Ice Age show regional differences. For the future, the results suggest that all sites will face massif warming and/or degradation of permafrost, with possible consequences related to reduction of slope stability in mountains and increased green house gas emissions, especially in the wetlands of northern Norway.
12036006 Euskirchen, E. S. (University of Alaska Fairbanks, Institute of Arctic Biology, Fairbanks, AK); Edgar, C.; Turetsky, M. R.; Harden, J. W. and McGuire, A. D. Quantifying CO2 fluxes across a gradient of permafrost in boreal Alaska [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41F-04, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Changes in vegetation and soil properties following permafrost degradation and thermokarst development may cause changes in net carbon uptake, either by stimulating primary productivity due to changes in vegetation composition or by stimulating soil microbial decomposition. In order to better understand these dynamics, we established three sites in interior Alaska across a gradient of permafrost in which permafrost varies in presence and stability. These sites include a black spruce ecosystem with cold soils and stable permafrost, a permafrost collapse scar with thermokarst formation, and a moderately rich fen lacking near surface permafrost. Measurements at the sites include year-round eddy covariance estimates of CO2, water, and energy fluxes as well as the associated micrometeorological variables. During winter, the ecosystems each released approximately 15-25 g C m-2 mo-1. However, the black spruce ecosystem began to take up CO2 as soon as air temperatures increased in the spring, with an estimated accumulation of ~23 g C m-2 from late March to early May. During this same period, we observed unusually high rates of ecosystem respiration some days at the thermokarst site, potentially due to the release of trapped CO2 from frozen soil gas pockets. While the black spruce ecosystem continued to act as a net sink of CO2 in the summer, taking up ~2.5±1 g C m-2 d-1, the thermokarst and fen ecosystems remained CO2 sources, respectively releasing ~2.4±0.8 g C m-2 d-1 and ~1.9±1.1 g C m-2 d-1. While ecosystem respiration was similar across all three ecosystems during the summer (~4.8±1.0 g C m-2 d-1), gross primary productivity was much higher in the spruce ecosystem (~7.3±1.4 g C m-2 d-1) compared to the thermokarst (~2.5±0.9 g C m-2 d-1) and fen ecosystems (~3.0±1.1 g C m-2 d-1). These results suggest that in these boreal peatland ecosystems, permafrost thaw and thermokarst development will increase CO2 emissions to the atmosphere due to decreases in gross primary productivity. Furthermore, given that these ecosystems are in close proximity (<2 km apart), an accurate assessment of the spatial heterogeneity of carbon and water fluxes and stores by regional models should include ecosystems under a localized range of permafrost influence.
12035943 Fortier, Daniel (University of Montreal, Department of Geography, Montreal, QC, Canada); Coulombe, Sstephanie; Kanevskiy, M. Z.; Paquette, Michel; Shur, Y. and Stephani, E. Buried glacier ice in permafrost, a window to the past; examples from Bylot Island, Canadian Arctic [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41C-0418, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Bylot Island is located north of Baffin Island (73°N, 80°W) and is extensively covered by an ice cap and its outlet glaciers flowing towards the arctic lowland of the Lancaster formation. During summers of 2009 and 2011 several active-layer detachment slides exposed large massive ice bodies and other types of debris-rich ice that were interpreted as buried glacier ice. The upper part of the massive ice and debris-rich ice were usually in contact with various types of ice-contact or glacio-fluvial sediments and in some cases they were covered by mass wasting/colluvial deposits. This suggests that their preservation was likely related to burial of the ice and refreezing of the overlying sediments following permafrost aggradation. A preliminary analysis of the ice facies and ice crystals revealed the presence of four distinct types of ice: 1) clear-ice bodies with very few sediment and no organic inclusions. The ice crystals were large (cm), randomly oriented and air bubbles were observed at the junction of crystals. These characteristics could potentially indicate an englacial (snow-neve metamorphism) origin for these clear ice bodies; 2) large, meter thick, clear ice layers with no sediment, nor organics. The ice crystals were large (cm), several cm long, oriented in the same direction, and vertically aligned. These characteristics could potentially point to water that refroze in a tunnel incised in englacial ice; 3) Successive, mm to cm thick, ice layers, separated by undulating sand and gravel bands also containing cobbles to boulder size rock fragments. These characteristics could potentially represent regelation ice formed at the base of glaciers and incorporated to the glacier sole; 4) mm to cm suspended aggregate of fine-grained sediments in clear ice. These micro-suspended and suspended cryostructures were sometimes deformed and aligned in the form of thin (mm) undulating layers. These micro-structures were very similar to basal ice facies, presumably related to glacio-hydrologic supercooling, that we observed at the Matanuska Glacier in Alaska. Interestingly, the various types of ice contained in buried glacier ice permafrost date back to the englacial ice formation and its subsequent deformation by glacier flow and glacio-hydrological dynamics. It is thus older by several centuries to millennia than the permafrost aggradation itself (burial and active layer development) and we used the term antegenetic, in opposition to epigenetic or syngenetic, to characterize this type of permafrost. Buried glacier ice is a window to the past and a unique tool to reconstruct the paleogeography and paleoclimatology of Arctic regions. In a warming climate, as glaciers are receding, the burial of ice in the proglacial environment will offer opportunities to characterize antegenetic permafrost aggradation and its related cryofacies. In warming permafrost environments, as active layers on slope deepen and detachment slides are triggered, more buried Pleistocene glacier ice will likely be exposed.
12035934 Frauenfeld, Oliver W. (Texas A&M University, Department of Geography, College Station, TX) and Zhang, T. Observed station-based 1956-2000 soil heat flux anomalies at 423 sites across the Eurasian high latitudes [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0409, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
In response to climatic warming, soil temperatures are increasing, the active layer is thickening, and taliks are forming in permafrost regions. These changes are resulting in a delayed freeze-up of soils, decreased freeze depths in seasonally frozen ground regions, leading to earlier spring thaw and reemergence of soil temperature anomalies. These soil thermal regime changes potentially result in more and more heat storage in soils during the warm season and amplify frozen ground changes, thereby representing a terrestrial analog similar to Arctic amplification due to the loss of sea ice. Any anomalous soil heat flux to the atmosphere in the transitional and cold seasons from the increased soil heat storage potentially represents a previously unexplored land-atmosphere feedback, capable of altering the large-scale flow of the atmospheric circulation. Based on monthly historical soil temperature observations at 423 station locations in the Eurasian high latitudes, we calculate the heat flux at the surface to determine the potential changes since 1956. Based on a composite approach by comparing the early period (1956-1960) to the later part (1996-2000) of our record, we find that, indeed, significantly more heat flows into the soil during summer months, while less heat flows out of the soil during the winter months. This indicates a net storage of heat in the soil, and results in the observed increasing soil and permafrost temperatures. Long-term trends in annual net heat flux indicate statistically significant changes greater than 150 Wm-2 for the 45-year period. However, we find significant regions of both increasing and decreasing annual heat fluxes. Some of these patterns can be reconciled by focusing on the specific seasonality of the heat-flux changes as well as their spatial variability.
12035971 Gisnas, Kjerst (University of Oslo, Department of Geosciences, Oslo, Norway); Etzelmuller, Bernd; Farbrot, Herman; Westermann, Sebastian and Schuler, T. V. CryoGRIDequi; a new equilibrium permafrost model applied for Norway [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41B-0796, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
The thermal regime of permafrost is likely to change significantly in response to the predicted climate warming, with associated warming and degradation of permafrost. Knowledge about the spatial distribution and temperatures of permafrost is therefore crucial to understand the associated geomorphological and bio-chemical consequences. Based on spatially distributed equilibrium models (CryoGRIDequi) this presentation will focus on the effect of snow cover and organic material on the regional distribution of permafrost in Norway. In Norway, the good availability of spatially distributed data on meteorological variables, vegetation, petrophysics and sediment cover allows for an implementation of soil models with relatively high resolution, in our case 1 km2. CryoGRIDequi comprises implementations of both the TTOP-model and the Kudryavtsev approach. The model defines temperature at the top of permafrost from air temperatures based on seasonal n-factors, parameterizing the vegetation and snow cover, and the conductivity ratio between frozen and thawed states in the active layer. The models are run with operationally gridded temperature- and snow data from the period 1960-2010, provided by the Norwegian Meteorological Institute and the Norwegian Water and Energy Directorate (senorge.no). Parameterization of the model is based on data from several air/ground and snow depth stations established in various mountain sites. The modeling results are validated with 140 sites all over Norway measuring ground surface temperature, 20 shallow boreholes equipped with temperature monitoring logger devices and maps of palsa- and rock glacier locations. The modeled permafrost distribution is in good agreement with observations. Sporadic permafrost under organic cover, which is absent in previous regional modeling procedures, is now well reproduced. According to the model results, approximately 6% of the total mainland area in Norway is presently underlain by permafrost. Of the total permafrost area, 34% is found in till, 23% in blockfields and 17% in bedrock. The remaining areas are covered by mainly glacial sediments and organic material. Most permafrost in organic-rich material is found in northern Norway. Assuming the SRES A2 scenario with an air temperature increase of on average 3°C until 2100, permafrost is modeled to disappear almost entirely in the mountains of Southern Norway, while permafrost will degrade in about 90% of the present area in Northern Norway. Since most of the permafrost in Northern Norway occurs in mires, this might result in an increase in greenhouse gas emissions from these areas.
12035936 Godin, Etienne (University of Montreal, Department of Geography, Montreal, QC, Canada) and Fortier, Daniel. Fine scale monitoring of ice ablation following convective heat transfer; case study based on ice-wedge thermo-erosion on Bylot Island (Canadian High Arctic) and laboratory observations [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41C-0411, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Thermo-erosion gullies often develop in ice-wedge polygons terrace and contribute to the dynamic evolution of the periglacial landscape. When snowmelt surface run-off concentrated into streams and water tracks infiltrate frost cracks, advective heat flow and convective thermal transfer from water to the ice-wedge ice enable the rapid development of tunnels and gullies in the permafrost (Fortier et al. 2007). Fine scale monitoring of the physical interaction between flowing water and ice rich permafrost had already been studied in a context of thermal erosion of a large river banks in Russia (Costard et al. 2003). Ice wedge polygons thermo-erosion process leading to gullying remains to be physically modelled and quantified. The present paper focus on the fine scale monitoring of thermo-erosion physical parameters both in the field and in laboratory. The physical model in laboratory was elaborated using a fixed block of ice monitored by a linear voltage differential transducer (LVDT) and temperature sensors connected to a logger. A water container with controlled discharge and temperature provided the fluid which flowed over the ice through a hose. Water discharge (Q), water temperature (Tw), ice melting temperature (Ti) and ice ablation rate (Ar) were measured. In laboratory, water at 281 Kelvin (K) flowing on the ice (Ti 273 K) made the ice melt at a rate Ar of 0.002 m min-1, under a continuous discharge of »8´10-7 m3 s-1. In the field, a small channel was dug between a stream and an exposed ice-wedge in a pre-existing active gully, where in 2010 large quantities of near zero snowmelt run-off water contributed to several meters of ice wedge ablation and gully development. Screws were fastened into the ice and a ruler was used to measure the ablation rate every minute. The surface temperature of the ice wedge was monitored with thermocouples connected to a logger to obtain the condition of the ice boundary layer. Discharge and water temperature were measured in the excavated channel just before the water got in contact with the ice surface. The field experiment where flowing water at Tw=277 K, Ti=273 K with a water discharge of 0.01 m3 s-1 resulted in a measured Ar of 0.01 to 0.02 m min-1. Water discharge and temperature difference between water and the melting ice were fundamental to ice ablation rate. The recent climate warming in the Canadian High Arctic will likely strongly contribute to the interaction and importance of the thermo-erosion and gullying processes in the High Arctic. Combined factors such as earlier or faster snowmelt, precipitation changes during the summer and positive feedback effects will probably increase the hydrological input to gullies and therefore enhance their development by thermo-erosion.
12035923 Godsey, S. (Pennsylvania State University, University Park, PA); Gooseff, M. N. and Lewkowicz, A. G. Controls on the spatiotemporal evolution of the thawed layer in and around thermokarst features [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0398, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Thermokarst formation leads to changes in ground temperature as well as increases in active layer thickness. These changes reflect a combination of shifts in the surface energy balance, conductive heat transport, and non-conductive heat transport. Changes in the surface energy balance occur when the vegetation and organic soil horizons are removed during ground collapse, changing the albedo inside the thermokarst feature. Conductive heat transport is also affected by the removal of these surface layers because they typically have different thermal properties than the underlying mineral soil. Additionally, thermokarst formation can increase surface topographic gradients, potentially altering soil moisture status, and thus, thermal conductivity inside thermokarst features. Finally, increased topographic gradients may increase water fluxes through these features, leading to additional non-conductive heat transport. We present field evidence from six sites in arctic Alaska describing shifts in ground thermal regimes associated with thermokarst formation, and the relative importance of changes in surface energy balance, conductive heat transport, and non-conductive heat transport. We also show model results that suggest that conductive heat transport may be sufficient to explain observed changes in ground thermal regimes and thaw depths. Large changes in the surface energy balance and non-conductive heat transport are not required, but cannot be excluded. Finally, we discuss potential feedbacks and the role of interannual legacies on controlling ground temperatures in regions of permafrost degradation.
12035920 Harada, K. (Miyagi University, Sendai, Japan); Narita, K.; Saito, K.; Sawada, Y. and Fukuda, Masami. Variations of permafrost conditions after wildfire in Alaska [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0395, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
In the Arctic area, wildfire affects the ground surface condition of permafrost due to its heat and disappearance of surface moss layer, and these may cause the variation of permafrost condition. In the Seward Peninsula, Alaska, large tundra fires occurred in 1971 and 2002, and a discontinuous permafrost area burned widely near the Kougarok River. After fires, a surface vegetation condition was destroyed and a ground surface thermal condition was changed. The research objective is to understand variations of permafrost distribution and condition, and of thermal and water conditions in active layer. Field observations were conducted at burned and unburned sites in summer since 2005. The same measurements were made at the each north- and south-facing slope, and their thermal and water conditions were compared each other. Thaw depths at burned sites are deeper than those at unburned sites, but not so deep. Differences of thaw depth seem to decrease year by year. At only north-facing sites, the continuous record of temperature at the depth of 30 cm showed that there was no significant difference between burned and unburned sites in 2008 and 2009 winters. At the burned site, the ground at the depth of 30 cm began to freeze earlier than that at the unburned site, but later at the south-facing site. This early beginning of ground freezing may cause the small difference of temperatures. From continuous measurements, the water content at the burned site showed lower value than that at the unburned site in fall. This low water content may cause the small difference of temperature in winter time. Vegetation surveys show that the vegetation recovery pattern varied in relation to the thaw depth. We measured the surface roughness and those at burned sites are higher than those at unburned sites. This difference of roughness corresponds to the difference of a parameter calculated from ALOS PALSAR image. As another observations show that the field rough surface can be lower temperature due to the effect of convection, the low temperature area can be detected from the satellite image.
12035968 Hasan, Abdulghani A. (Lund University, Earth and Ecosystem Sciences, Lund, Sweden). Modeling the effect of soil wetness and air temperature on the active layer thickness [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41B-0792, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
This study presents a dynamic distributed model that models the effect of thawing permafrost on local topography and the active layer thickness in subarctic mire in Abisko, Sweden. A new approach using a Topographical Wetness Index (TWI) is presented based on the slope difference between any cell and the surrounding grid cells. The TWI is used to estimate the water content distribution to all cells in the grid within the study area. The model consists of three main parts input datasets, main equation for calculations of thawing depth and the output data. The model is dynamic, meaning that some input data like soil moisture is going to be updated according to the results in the previous time step. Same thing with the climate data, it is dynamically changed according to the predicted future data for this area. The active layer thickness (ALT) is calculated in this model as a maximum thawing depth for one year time step. All calculations were depending on different variables involving the hydrology and climate in peatlands. The model is run to calculate the ALT in each (0.5´0.5 m) grid cell and is repeated for all cells in the grid. The study has showed the possibility of using an analytically based approach with semi empirical equations to calculate the maximum thawing depth of permafrost. It also proves that the topographical wetness index TWI can be used to redistribute the soil water/ice content to all cells in a grid. Our model shows that the average change in the active layer thickness for Stordalen mire will be around +46 cm. a predicted changing of the current mean annual air temperature from 0 to +1 C may lead to the permafrost may disappear from a large part of the study area. A negative finding about our permafrost model is that the model is very sensitive to the changes in some variables. It is good to note that in order to use the permafrost model for future prediction in any region, the model should be validated using field data.
12035973 Heim, Birgit (Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany); Bartsch, A.; Elger, Kirsten K.; Boike, J.; Lantuit, Hugues; Muster, Sina; Langer, M.; Duguay, C. R.; Hachem, S.; Soliman, A. S.; Rinke, Annette; Matthes, Heidrun and Klehmet, Katharina. ESA DUE PERMAFROST; remote sensing service for permafrost; adaption for models [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41B-0798, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
The ESA DUE Permafrost project (2009-2011) is developing a suite of parameters indicative of the subsurface phenomenon permafrost using satellite remote sensing: Land Surface Temperature (LST), Surface Soil Moisture (SSM), Surface Frozen and Thawed State (Freeze/Thaw), Terrain, Land Cover (LC), and Surface Water (SW). Snow parameters (Snow Extent and Snow Water Equivalent) are being developed through the DUE GlobSnow project, Global Snow Monitoring for Climate Research (2008-2011). The final DUE Permafrost remote sensing products cover the years 2007 to 2011 with a circumpolar coverage that will soon be released (early 2012), and then be used to analyze the temporal dynamics and map the spatial patterns of indicators. Further information is available at www.ipf.tuwien.ac.at/permafrost. Since the beginning, scientific stakeholders and the International Permafrost Association (IPA) have been involved in the science and implementation plan. Interactive international user workshops took place in 2010 at the Technical University of Vienna, Vienna (AT), and in 2011 at the International Arctic Research Center (IARC), Fairbanks, Alaska (US). This involvement and the ongoing evaluation of the indicators derived from remote sensing for the high-latitude permafrost regions make the DUE Permafrost products trustworthy for the permafrost and the climate research community. The adaption of the remote sensing products for the permafrost and climate modelling is experimental and highly dependent on the users' involvement. For a few years already, the Geophysical Institute Permafrost Laboratory (GIPL), University of Alaska Fairbanks, US, (URL: http://www.gi.alaska.edu/research/snowicepermafrost/Permafrost) has successfully demonstrated the value of using LST derived from remote sensing data for driving its permafrost models. Further experimental testing of the DUE Permafrost products for use by the modeling community (permafrost and climate) will range from (i) the evaluation of external data of the models, with modifying or providing new external data (e.g. tundra land cover, surface water ratio, soil distribution), to (ii) new drivers for regional models derived from remote sensing (e.g., LST), to (iii) the evaluation of the output data from the models (e.g. spatial patterns of moisture and temperature).
12036009 Hicks Pries, C. E. (University of Florida, Department of Biology, Gainesville, FL) and Schuur, E. A. Using D14C and d13C to partition ecosystem respiration in a permafrost warming experiment [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41F-07, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Ecosystems underlain by permafrost contain vast stores (1672 Pg C) of soil carbon (C). As climate warming causes permafrost soils to thaw, this soil C that previously protected from decomposition is released into the atmosphere as CO2 or methane, causing further climate warming. However, warming can also increase plant productivity and therefore C storage, a negative feedback to climate change. We quantified whether plants or soil were driving increases in Reco measured in a permafrost warming experiment (CiPEHR) using D14C and d13C to partition ecosystem respiration (Reco) into four sources--two autotrophic (above- and belowground plant structures) and two heterotrophic (shallow and deep soil). We sampled the D14C and d13C of sources using incubations and the D14C and d13C of ecosystem respiration using field measurements. We measured how source contributions change with summer, winter, and annual warming. Plant respiration increased relative to the control as a result of warming with the largest increases occurring in the annual warming treatment. Thus, in the second year of the experiment, warming increased autotrophic contributions to ecosystem respiration. This result is in contrast to results from a natural permafrost thaw gradient where more extensive permafrost thaw increased the contribution of respiration from old, deep soil. However, in the natural thaw gradient, thaw has been ongoing for at least two decades. Therefore, warming in permafrost ecosystems may at first lead to increases in plant respiration, a neutral or negative feedback to climate change, but may eventually lead to increases in deep soil respiration, a positive feedback to climate change.
12035942 Kanevskiy, M. Z. (University of Alaska Fairbanks, Fairbanks, AK); Shur, Y.; Jorgenson, T. T.; Sturm, Matthew; Bjella, Kevin; Bray, M.; Harden, J. W.; Dillon, Matthew; Fortier, Daniel and O'Donnell, J. Pleistocene ice-rich yedoma in interior Alaska [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41C-0417, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Yedoma, or the ice-rich syngenetic permafrost with large ice wedges, widely occurs in parts of Alaska that were unglaciated during the last glaciation including Interior Alaska, Foothills of Brooks Range and Seward Peninsula. A thick layer of syngenetic permafrost was formed by simultaneous accumulation of silt and upward permafrost aggradation. Until recently, yedoma has been studied mainly in Russia. In Interior Alaska, we have studied yedoma at several field sites (Erickson Creek area, Boot Lake area, and several sites around Fairbanks, including well-known CRREL Permafrost tunnel). All these locations are characterized by thick sequences of ice-rich silt with large ice wedges up to 30 m deep. Our study in the CRREL Permafrost tunnel and surrounding area revealed a yedoma section up to 18 m thick, whose formation began about 40,000 yr BP. The volume of wedge-ice (about 10-15%) is not very big in comparison with other yedoma sites (typically more than 30%), but soils between ice wedges are extremely ice-rich--an average value of gravimetric moisture content of undisturbed yedoma silt with micro-cryostructures is about 130%. Numerous bodies of thermokarst-cave ice were detected in the tunnel. Geotechnical investigations along the Dalton Highway near Livengood (Erickson Creek area) provided opportunities for studies of yedoma cores from deep boreholes. The radiocarbon age of sediments varies from 20,000 to 45,000 yr BP. Most of soils in the area are extremely ice-rich. Thickness of ice-rich silt varies from 10 m to more than 26 m, and volume of wedge-ice reaches 35-45%. Soil between ice wedges has mainly micro-cryostructures and average gravimetric moisture content from 80% to 100%. Our studies have shown that the top part of yedoma in many locations was affected by deep thawing during the Holocene, which resulted in formation of the layer of thawed and refrozen soils up to 6 m thick on top of yedoma deposits. Thawing of the upper permafrost could be related to climate changes during Holocene or to wildfires, or both. The ice-poor layer of thawed and refrozen sediments (gravimetric moisture content usually does not exceed 40%) was encountered in many boreholes below the thin ice-rich intermediate layer (gravimetric moisture content usually exceeds 100%). These two layers separate ice wedges from the active layer and protect them from further thawing. Such structure of the upper permafrost at different yedoma sites of Interior Alaska can explain a relatively rare occurrence of surface features related to yedoma degradation such as thermokarst mounds and erosional gullies developed along ice wedges.
12035935 Khilimonyuk, Vanda (Moscow State University, Department of Geology, Moscow, Russian Federation); Pustovoit, G. and Filatova, M. Impact of black dust pollution on permafrost temperature regime in Pechora Basin [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0410, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Pechora Coal basin locates in North- Easter part of Europe within permafrost zone. The coal mining and post processing lead to emission of black dust (BD) and pollution of Earth surface. The scale of snow pollution surrounding Vorkuta city reaches to 260 g/sq.m of dust that is about 1000 ppmm BD concentration in snow before melting period. Such a large concentration of dust reduces snow reflectivity (Warren and Wiscombe, 1980; Chylek et al., 1983, Gorbacheva, 1984, Zender et al, 2010) and can thereby trigger albedo feedbacks. The goal of this study is to evaluate the role of dirty surface albedo in the observed changing of permafrost regime in this basin. Two key sites: Workuta (North permafrost zone) and Inta (South permafrost zone) areas were selected for this study. For each site the zoning of territory by typical conditions of permafrost formation was performed. For the selected typical landscapes 1-D vertical heat transfer model coupled with the surface radiation-thermal balance equation at topsoil was simulated. The simulation was performed for the soil profile of 20 m depth during 20 years period with periodical input data at dirty surface averaged on monthly base. The initial measured not disturbed soil temperature profile was used for assessment the soil thermal property for the given landscape and natural surface radiation-thermal balance. The annual cycle of albedo change for dirty surface was taken from experimental measurement (Gorbacheva, 1984) for both sites as the function of the distance from the dust source. The simulation results next were used for mapping the vulnerability of permafrost thermal regime due to black dust pollution. Generally the simulation results show that South permafrost zone with mean temperature of permafrost (-0.5 to -0.1C) is more vulnerable to albedo change than North permafrost zone with mean temperature (-2.5 to -2C) for the same order of dust impact on albedo.
12035974 Klene, Anna E. (University of Montana, Department of Geography, Missoula, MT); Yoshikawa, K.; Streletskiy, D. A.; Brown, Jerry; Nelson, F. E. and Shiklomanov, N. I. Temperature regimes in traditional Inupiat ice cellars in Barrow, Alaska [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41B-0799, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Historically ice cellars excavated in permafrost (perennially frozen ground) have been essential to Arctic residents and remain so today. These traditional facilities allow secure, year-round frozen storage of subsistence harvests over long periods. Inupiat peoples in Barrow, Alaska, have many of these cellars, some of which were created more than a century ago. Others were established recently and continue to be enlarged. Temperatures within the cellars are critical because bacteria can damage meat even at temperatures below the freezing point. These cellars generally have temperatures close to those of surrounding permafrost. Climatic change has been suspected of compromising and causing damage to ice cellars in some northern communities, with thaw and spoilage of meat occurring in some cases. Beginning in 2005, local residents and the Native Village of Barrow organization provided access to their ice cellars and miniature temperature data loggers programmed to record at hourly intervals were installed. Cellars at a variety of depths, locations relative to the coast, and age were included in the survey. Analysis of the five years of record revealed seasonal variations within each cellar, temperature changes over time within some cellars, and temperature differences between the five cellars examined. Winter ventilation to artificially cool the cellars, local snow drifting, and proximity to brine-saturated sediments contribute to differences in ambient ground conditions. Long-term temperature measurements in these and other cellars are needed to better understand the observed changes.
12036010 Koven, C. D. (Lawrence Berkeley National Laboratory, Earth Sciences Division, Berkeley, CA); Riley, W. J.; Subin, Z. M.; Tang, Jinyun; Torn, M. S.; Lawrence, D. M.; Bonan, G. B. and Swenson, S. C. Permafrost carbon and nitrogen dynamics in CLM4 [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41F-08, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Permafrost soils hold large quantities of C, which have the potential to act as a positive feedback to climate change. Decomposition rates may increase with warming, leading to a loss of C from these stocks as either CO2 or CH4. However, N mineralized from permafrost C may fertilize plant growth, thereby enhancing C assimilation and ecosystem C stocks. These dynamics explicitly depend on soil depth, particularly in high-latitude systems, yet most Earth System Models (ESMs) do not account for depth differences in C and N dynamics or physical mixing processes. To explore these dynamics within an ESM framework, we have developed a vertically-resolved representation of soil C and N dynamics in CLM4. The model includes the effects of temperature, moisture, and anoxia on decomposition, and vertical mixing on SOM profiles. The impacts of considering vertically-resolved processes on predicted high-latitude C stocks are large, and show high sensitivity to soil mixing rates, N cycle processes, and other processes. We present results showing the sensitivity of steady-state and future transient C and N dynamics to multiple processes and parameters.
12035946 Lanan, K. M. (Idaho State University, Department of Geosciences, Pocatello, ID) and Crosby, B. T. Can mapping glacial deposits help predict the location of future thermal erosion features in Arctic Alaska? A study from the Selawik River basin, northwest Alaska [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41C-0421, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Because interior Alaska was never fully glaciated, it preserves one of the best geomorphic records of Pleistocene glaciation in high-latitude North America. As a consequence, regional surface and glacial mapping has provided a terrestrial climatic record in the Arctic over the last ~200 k years. The Selawik River basin lies near the southwest margin of the ice extent for Alaska's Brooks Range, but has never been mapped. The Selawik basin also hosts the largest active retrogressive thaw slump (RTS) known in Alaska which impacts aquatic ecosystems and native villages downstream. In order to understand how the type and distribution of glacial deposits (and associated frozen ground) predispose certain areas to current and future thermokarst features, we have begun to develop a surface geology map and conceptual model outlining the glacial history of the region. The project combines field observations, geochronological sampling and remote sensing analysis. Detailed sedimentological analysis was performed in 2011 using large river bluff exposures along the upper Selawik River to explore stratigraphic relationships and provenance of clasts. We found that the exposures are comprised of interbedded sands and gravels with patchy diamict, suggesting an ice retreat sequence topped by a braided outwash plain. The lithology of striated clasts in the section confirms that sediment was sourced from the Brooks Range to the north rather than the more local Waring or Purcell mountains. A pronounced decrease in grain size and proportion of diamict toward the west suggests that sediment was moving toward the Chukchi Sea. A thin exposure of fine glassy sediment within the section is suggested to be the 140 ka Old Crow Tephra, indicating deposition during the beginning of the last interglacial stade. Bluffs are topped by thin, fine-grained deposits suggesting that the last glacial period did not deposit glacial till or outwash on the bluff. Either the Selawik basin was too distal from the lesser last glacial ice to receive coarse sediment or incision of the bluff occurred prior to the last glacial deposition and that sediment covers the valley floor. Ages of stratigraphic units will be constrained using OSL, radiocarbon and tephrochronology. Extrapolation of observations from river bluff exposures across the basin is supported by analysis using both visible and infrared stereo imagery. Each of five active RTSs identified along the river occurs within a diamict or silt unit. We suspect that these units may be more prone to large thermal erosion features because units with higher proportions of fines retain thawed fluids and efficiently transport sediment off surfaces, continually exposing deeper frozen ground. Though it is not evident in the large active slump, diamict is also commonly associated with unstable buried glacial ice. Identifying relationships between Quaternary depositional units and their susceptibility to thermal erosion will help land mangers predict which areas are most prone to future instability.
12035919 Lemay, Mickael (Université Laval, ArcticNet, Quebec City, QC, Canada) and Allard, Michel. Permafrost and climate change in Nunavik and Nunatsiavut; importance for municipal and transportation infrastructures [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0394, illus., December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Permafrost degradation is seriously affecting the natural environment. The landscape is changing through thermokarst that takes place mostly in the discontinuous permafrost zone and through increased active layer depth and more frequent slope processes in the continuous zone. Northern residents are affected as vegetation, water bodies and soil drainage are greatly modified, which has an impact on resources traditionally available for humans such as berries that are shaded in the understory of shrubs that expand in thermokarst hollows. The modern built environment is particularly affected. Essential transportation infrastructures are being studied and adaptive solutions are sought, applied and tested. To protect and optimize the major investments required for extensive housing and construction, the urban planning of communities calls upon better permafrost maps and prediction of permafrost behavior. Final permafrost degradation around 0°C appears to be in great part under the influence of unfrozen water contents and heat brought at the thawing interface by groundwater. This process is also effective in accelerating localized thawing under human infrastructures. Collection and organization of permafrost information in geographic information systems (GIS) allows the integration of essential knowledge and provide very useful tools for sharing information with stakeholders and communities, for establishing diagnostics of situations and for supporting multidisciplinary decision making for land use planning. The principal adaptive measures lie in adapting foundations types to mapped permafrost conditions to ensure a prolonged service life of buildings.
12035926 Lewkowicz, A. G. (University of Ottawa, Department of Geography, Ottawa, ON, Canada); Etzelmuller, Bernd and Smith, Sharon. Effect of shallow ponding on warming and thawing of permafrost in mineral-cored palsas, Wolf Creek, Yukon, Canada [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0401, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Few measurements exist of the effect of shallow water bodies on ground temperatures in the discontinuous permafrost zone. However, such ponds could become more common under climate warming and could affect rates of thaw of frozen ground and subsequent carbon release. To examine these effects, permafrost temperatures were monitored manually or continuously using temperature-loggers in six mineral-cored palsas (permafrost-cored mounds) located on a valley floor at treeline in the Wolf Creek basin near Whitehorse. The mounds were instrumented in 2004 in anticipation of water-level changes due to dam construction by beavers (Castor canadensis). Over this period beaver activity has raised water levels and created larger water bodies adjacent to all of the palsas, resulting in ground temperature increases and permafrost degradation. The ponds are shallow and some freeze to the bottom in winter, but their mean annual temperatures are higher than on adjacent exposed surfaces and they therefore warm the palsas laterally, eventually causing block collapse. A 7-year record of temperatures from a previously stable palsa, shows slight but progressive warming at the base of permafrost (at 7 m) since it was surrounded by water in 2009. Other palsas which were already degrading in 2001 are experiencing higher rates of warming and are rapidly settling beneath the water. Internal changes in unfrozen water contents within the palsas were revealed by differences between pairs of DC electrical resistivity profiles recorded in spring 2006 when most forms were stable, and repeated in spring 2011 when most were degrading. The rapidity of permafrost change when warmed by water illustrates the potential for drainage changes to dramatically increase heat flow through convection and hence to speed up rates of permafrost degradation.
12035939 L'Hérault, Emmanuel (Centre for Northern Studies, Quebec City, QC, Canada); Allard, Michel; Doré, Guy; Barrette, Carl; Verreault, Jean; Sarrazin, Denis; Doyon, Jeremie and Guimond, Anick. Assessment of permafrost conditions under northern Quebec's airports; an integrative approach for the development of adaptation strategies to climate warming [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41C-0414, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Community airports in Nunavik were built between 1984 and 1992 and were designed by using a thick embankment of rock fill placed on undisturbed ground surface to prevent the thawing of the underlying permafrost. However, since around 2000, many of the runways show signs of permafrost disturbance as some localized differential settlements have begun to take place. With the anticipated rise of air temperature, the vulnerability of transportation infrastructures to permafrost degradation raises concerns. Several studies initiated by MTQ were undertaken by CEN to evaluate the permafrost conditions underneath airports. These studies provide valuable baseline information but also reveal the needs for a better understanding of the spatial variability of the surficial deposits, their geotechnical properties and permafrost conditions underneath embankments to assess its sensibility to thawing and to plan adaptation strategies in face of climate warming. A geomorphological and geotechnical investigation campaign, including surficial geology mapping using pre-construction air photographs and recovery of drilled frozen cores, was carried out in the summers 2008 and 2009 at eight airports. The impact of the runway embankments on surface drainage, snow drift accumulation and permafrost thawing was also determined. Stratigraphic information from drilling was used to reinterpret CCR and GPR surveys done in previous studies. High resolution cross-sections of the stratigraphy and permafrost conditions could then be drawn. Lab testing over undisturbed frozen samples was performed to determine the geotechnical properties of the different stratigraphic units encountered, particularly thaw consolidation ratios. Field measurements of ground temperatures and numerical modeling of the thermal regime of the embankment and subgrade were also performed to assess the potential impacts on permafrost stability alongside and beneath embankments under different climate change scenarios. Thermistor readings show that the active layer in the central part of the runways is in most case still contained in the embankment or within the prior-to-construction consolidated active layer. However, a residual thaw layer (talik) is now present at the toe of embankments where significant snow accumulations occurred. Thermal modeling indicates that water accumulation and seepage as well as snow accumulation along embankment shoulders are currently the dominant factors of permafrost degradation. In the future, centerlines of embankment built on ice rich permafrost will gradually settle as the climate warms up; therefore periodic reloading will be necessary. To counter permafrost degradation alongside runways and access roads, the proposed mitigation strategies focus on minimizing snow and water accumulation by making gentler slopes (1:6) and by improving the drainage system to avoid potential seepage through embankments.
12035951 Liljedahl, A. K. (University of Alaska Fairbanks, Water and Environmental Research Center, Fairbanks, AK); Hinzman, L. D.; Schulla, J.; Tweedie, C. E. and Zona, Donatella. Micro-scale topographical controls on Arctic watershed-scale hydrologic fluxes and stocks [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41C-0426, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
There is a lack of multi-year field studies in low-gradient tundra landscapes that include measurements of all components of the water balance. This data gap complicates efforts aimed at increasing understanding of hydrologic processes in arctic ecosystems and increases uncertainty in model projections. We assessed the recent (1999-2009) water balance of a wetland near Barrow, Alaska, to gain knowledge of interannual hydrologic variations and controls at an ice wedge polygon tundra by combining an extensive field campaign with the physically-based model WaSiM-ETH. Evapotranspiration was the major pathway of water loss from the watershed (160 mm/yr) accounting for 77% of mean annual adjusted precipitation (208 mm). Still, interannual variations in total summer precipitation (total mean summer precipitation was 93 mm) defined the primary differences in autumn soil water storage and, therefore, the partitioning of snowmelt water into runoff and soil and surface water storage. Measured runoff (2007-2009) represented on average 60% of the measured end-of-winter snow water equivalent with large interannual variations (from 34 to 91%). Summer runoff was low. Micro-topographic features are quite important in low-gradient tundra wetlands. The >3 week observed ponding period following snowmelt was only replicated by WaSiM-ETH when rims of low-centered polygons were represented in the digital elevation model. The model results, which were supported by the field measurements, suggest a) interannual hydrologic connectivity through changes in soil water storage controls the partitioning of the melting snowpack in spring and b) dependence of watershed-scale hydrology on subtle terrain features such as low-centered ice wedge polygons. The results highlight the need for high-resolution digital elevation models, long-term direct evapotranspiration measurements, and fine-resolution modeling in order to further understand the impact of subtle changes in surface topography, as is expected to occur with permafrost degradation in response to a warming climate.
12035972 Liu, Lin (Stanford University, Department of Geophysics, Stanford, CA); Zebker, H. A.; Zhang, T.; Westfall, R. D. and Millar, C. I. Monitoring surface deformation in polar, alpine, and plateau periglacial environments from space using radar interferometry [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41B-0797, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Widespread and systematic changes in the permafrost and active layers could have profound effects on biological, biogeochemical, hydrologic, and landscape processes, on the flux of greenhouse gases, and on human infrastructure. Thawing of ice-rich permafrost in alpine areas can lead to rapid mass wasting, including active-layer detachment, retrogressive thaw slumps, rock glacier movement, and even more catastrophic events such as landslides, debris flow, and rock falls. We apply radar interferometry (or InSAR) technique to the Phased Array type L-band Synthetic Aperture Radar (PALSAR) data acquired by the Advanced Land Observing Satellite (ALOS) satellite to monitor changes in permafrost and in the active layer in polar, alpine, and plateau periglacial environments. Using InSAR, we are able to map the surface deformation over large area (typically 70 km by 100 km), at a high spatial resolution up to about 10 m, at an interval as short as 46 days. Specifically, near Deadhorse and Barrow on the Arctic coast of Alaska, we detect seasonal thaw settlement and frost heave of 2 to 4 cm. In the Sierra Nevada of California, we find surface deformation of 5 to 20 cm within three summer months over the Barney Lake and Gibbs rock glaciers. On the Qinghai-Tibet Plateau, we map active layer thaw slumps near the Qinghai-Tibet highway and compare our space-geodetic measurements with ground measurements. Using the radar data acquired by the same sensor, we will compare the spatial and temporal characteristics of these surface motions. We will also present our estimates of long-term trends in surface deformation in the polar and plateau study areas and discuss their associations with increasing ground temperatures. Field data on rock temperatures indicate that active rock glaciers are highly resistant to warming surface temperatures. Therefore, we expect little long-term trends in rock glacier motions.
12035977 Max, Michael D. (Hydrate Energy International, New Orleans, LA) and Johnson, Art H. Vein-type natural gas hydrate in permafrost cryosphere regions; potential for sudden step increase in positive greenhouse feedback [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41B-0802, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Newly recognized, shallow vein-type permafrost hydrate deposits have been identified in Alpine permafrost terrain of the Qinghai-Tibet plateau in western China. These vein-type deposits appear to have been formed when natural gas was introduced in fractures within, and associated with, frozen ground in permafrost terrane. Vein-type hydrate appears to have been formed through an ice-water interaction in ice zones and is not contained within secure geological traps that would contain the gas if the hydrate converts to water and natural gas. It is possible that unrecognized vein-type hydrate in Arctic permafrost regions in Eurasia and North America also may be present at relatively shallow depths, particularly if higher density hydrocarbon gases are present along with methane. If vein-type gas hydrate exists in quantity, its dissociation may yield much larger amounts of hydrocarbon natural gases to the atmosphere than have been currently modeled. Initiation of dissociation in vein-type permafrost hydrate may result in an unwelcome step increase in positive feedback of the atmospheric greenhouse as the thawing permafrost reaches the upper part of the gas hydrate stability zone.
12036003 McGuire, A. D. (University of Alaska Fairbanks, Alaska Coop Fish Wildlife Unit, Fairbanks, AK); Christensen, Torben R.; Hayes, D. J.; Heroult, Arnaud; Kimball, John S.; Koven, C. D.; Lafleur, P.; Miller, Paul; Oechel, W. C.; Sitch, S. and Williams, Mat D. An assessment of the carbon balance of Arctic tundra; comparisons among observations, process models, and atmospheric inversions [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41F-01, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Although Arctic tundra has been estimated to cover only 8% of the global land surface, the large and potentially volatile carbon pools currently stored in Arctic soils have the potential for large emissions of radiatively active greenhouse gases in the form of both CO2 and CH4 under warmer conditions, resulting in a positive feedback to global warming. Given the potential sensitivity of Arctic tundra to climate change and the expectation that the Arctic will experience appreciable warming over the next century, it is important to assess whether responses of carbon storage in Arctic tundra are likely to enhance or mitigate warming. In this analysis we compare estimates of carbon dynamics of Arctic tundra between 1990 and the late 2000s among observations, process-based models, and inversion models. A synthesis of compiled flux observations for Arctic tundra indicates that the annual exchange of CO2 cannot be distinguished from neutral balance across the range of studies that have been conducted. The process-based models indicate that the net ecosystem production of Arctic tundra ranged between 10 and 30 g C m-2 yr-1 from 1990-2006. Only one of the process-based models estimates that NEP is increasing in the 1990s and 2000s. Three of the four process-based models have a similar range of interannual variability in GPP, NPP, RH, and NEP. GPP, NPP, and RH are generally well correlated among the models, but the interannual variability in NEP is poorly correlated among the models.
12035911 McKenzie, Jeffrey M. (McGill University, Department of Earth & Planetary Sciences, Montreal, QC, Canada) and Voss, C. I. The importance of groundwater flow in thawing permafrost systems [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0386, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Arctic hydrology systems are undergoing rapid changes due to climate change, such as increases in arctic river discharge and carbon export, and the disappearance of arctic lakes. As permafrost (ranging from several meters to hundreds of meters in thickness) thaws from above, a deeper seasonal active zone (the shallow subsurface layer that freezes and thaws annually) develops, and more through-going thawed zones (i.e. taliks) develop that connect the supra- and sub-permafrost zones. These unfrozen pathways can allow a dramatic increase of interaction between groundwater and surface water. Despite this potential for increasing groundwater movement in warming arctic environments, predictive models of permafrost thaw and distribution generally consider only the conduction of heat through the subsurface, and do not incorporate advective heat transport (movement of heat due to flow). To understand these systems and potential feedbacks, the SUTRA numerical groundwater model, which couples groundwater flow and heat transport, was modified to include freezing processes. When temperatures are below freezing, the model simulates variable saturation, permeability, and thermal properties as a function of ice saturation, and includes the latent heat of formation of ice. We simulated groundwater flow and permafrost thawing across a four-kilometer-long hillslope cross section, with sinusoidal hills and valleys, which has an initially continuous permafrost layer. The mean air-temperature increases by 0.5°C per 100 years for 1600 years, and temperature is constant thereafter. This long-term warming trend is superimposed on a seasonal ±10°C temperature variation that drives the yearly freeze/thaw cycle in the shallow subsurface. Simulation results compare changes in permafrost distribution over a few thousand years of climate change due to (1) purely conductive heat transport (equivalent to essentially no groundwater flow) and (2) advective-conductive heat transport (equivalent to regions with significant groundwater flow). The results indicate that where groundwater flows, the advective transport of heat enhances the rate at which permafrost thaws, increasing transmissivity and the movement of warmer recharge water and deep water, further increasing the rate at which the edges of the permafrost warm and thaw, in a positive feedback. Where groundwater flows, it is a significant control on the rate of thaw and pattern of residual permafrost in the landscape.
12035991 Muskett, Reginald R. (University of Alaska Fairbanks, Geophysical Institute, Fairbanks, AK) and Romanovsky, V. E. Energy and mass changes of the Russian permafrost regions from multi-satellite and in-situ measurements [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41C-0823, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
We investigate changes in total water storage mass (GRACE), land-surface temperature (MODIS) and atmospheric CO2 (AIRS) satellite-based and in-situ (runoff and bias corrected precipitation) measurements from August 2002 through December 2008. Our region of interest spans 75 to 165E and 50 to 80N centered on the Lena River watershed as a physical reference frame. We find energy and mass changes on the continuous and discontinuous permafrost zones indicating: 1) Arctic uplands such as the Siberian Plateau show strongly positive water equivalent mass and strongly negative land-surface temperature gradients during May. 2) Arctic lowlands such as the thaw-lake regions of Kolyma, Lena Delta, and Taymyr and the wetlands near Yakutsk show strongly negative water equivalent mass and strongly positive land-surface temperature gradients during September. 3) Areas with strongly positive water equivalent mass and negative land-surface temperature gradients during May show weakly positive CO2 gradients, whereas areas of strongly negative water equivalent mass and strongly positive land-surface temperature gradients during September show strongly positive CO2 gradients. This indicates permafrost ecosystem response is in phase with energy and mass changes over the period of measurements.
12036008 Natali, S. (University of Florida, Department of Biology, Gainesvile, FL) and Schuur, E. A. Increased carbon loss from upland tundra with experimental warming and permafrost degradation [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41F-06, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Northern permafrost systems play a critical role in global carbon (C) cycling because of the vast pool of thermally-protected C stored in these ecosystems and the strong potential for changes in C storage in a warmer climate. Increased decomposition of previously frozen organic C may result in a significant positive feedback to global climate change; however, some respiratory C losses may be offset, in part, by warming-mediated increases in plant productivity. To determine the magnitude of warming effects on ecosystem C balance, we established a new warming experiment--the Carbon in Permafrost Experimental Heating Research (CiPEHR) project--where we increased air and soil temperatures and degraded surface permafrost. We used snow fences coupled with spring snow removal to increase deep-soil temperatures and thaw depth (winter warming) and open top chambers to increase summer air temperatures (summer warming). Here we present ecosystem C balance results from three years of experimental warming and permafrost degradation of upland tundra in Interior Alaska. Winter warming increased soil temperature (integrated 5-40 cm depth) by 1.5°C, which resulted in a 10% increase in growing season thaw depth. Surprisingly, the additional 2 kg of thawed soil C m-2 in the winter warming plots did not result in an increase in net growing season CO2 loss from this ecosystem. In contrast, winter warming treatment increased growing season CO2 uptake, which was a result of both higher net primary production and an inhibition of microbial decomposition by soil saturation at the base of the active layer. However, on an annual basis, winter warming caused a significant increase in net ecosystem CO2 loss, which was driven by a two-fold increase in ecosystem respiration during the snow-covered period. While most changes to the abiotic environment at CiPEHR were caused by the winter warming treatment, summer warming effects on plant and soil processes resulted in 20% increases in both gross primary productivity and growing season ecosystem respiration and significantly altered the age and sources of CO2 respired from this ecosystem. These results demonstrate the vulnerability of organic C stored in near surface permafrost to increasing temperature and the strong potential for warming tundra to serve as a positive feedback to global climate change.
12035996 Nicolsky, D. J. (University of Alaska Fairbanks, Geophysical Institute, Fairbanks, AK); Romanovsky, V. E.; Romanovskii, N. N.; Shakhova, N. E. and Semiletov, Igor P. Modeling sub-sea permafrost in the east Siberian Arctic shelf; the Laptev Sea region [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41C-0837, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
The present day interest in understanding whether and how methane, preserved in seabed reservoirs, can escape to the atmosphere suggests a need to review sub-sea permafrost observations and to re-examine available sub-sea permafrost models. Currently, the models of sub-sea permafrost evolution significantly vary in employed physical assumptions regarding the paleo-geographic scenario, geological structure, thermal properties, initial temperature distribution, and geothermal heat flux. This work aims to review the underlying assumptions of these models as well as to incorporate recent findings, and hence develop an up-to-date model of the sub-sea permafrost dynamics at the Laptev Sea shelf. In particular, the developed sub-sea permafrost model incorporates the thermokarst and land-ocean interaction theory, and shows that the sediment salinity and a temperature-based parametrization of the unfrozen water content are critical factors influencing sub-sea permafrost dynamics. From the numerical calculations, we suggest development of open taliks underneath submerged thaw lakes within a large area of the shelf.
12035984 Nissen, J. (Cloudworld, London, United Kingdom). Arctic methane workshop; an assessment of threats to Arctic and global warming; and an evaluation of techniques to counter these threats [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41B-0810, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
This is a report from a workshop especially convened in order to identify means to reduce the threat of methane being emitted from sources in the Arctic in such quantities as to have a major impact on global warming. Major factors in the assessment of this threat are the unexpectedly rapid retreat of sea ice [1] and the unexpectedly large quantities of carbon which might be emitted as methane [2]. The assessment takes into account the possibility of the Arctic Ocean becoming seasonably ice free this decade if there is no action to cool the Arctic. The report includes the latest work from Natalia Shakhova, Igor Semiletov and others on East Siberian Arctic Shelf (ESAS) - particularly concerning the present large emissions of methane and the possibility of sudden release of much larger quantities. Large releases could also occur from Arctic lakes and wetlands, and this threat will also be assessed. Work by Isaksen and others suggests that if emissions are increased from present levels by a factor of 2 or more, then not only is the lifetime of methane in the atmosphere increased, thus increasing the methane's global warming potential over time, but indirect radiative forcing is increased also [3]. If total methane emissions rise fivefold, as possible with a major discharge from ESAS, then the contribution to climate forcing, and hence global warming, could be greater than from the current level of atmospheric CO2. What can be done quickly to reduce this methane threat? The workshop's evaluation of various techniques to deal with the methane will be presented. A three-prong attack is proposed: 1. cooling the Arctic, regionally or locally, using Solar Radiation Management (SRM-type geoengineering); 2. management of the methane environment at the local level (see below); 3. capture or destruction of methane, already in the atmosphere. Local approaches can be categorised according to where the intervention action takes place. Where the methane is from lake or sea bed, the action could be: - below the permafrost, where there may already be methane or methane hydrate; - in the permafrost, or to plug gaps in the permafrost where methane is rising; - in the bed of the sea or lake, above the permafrost layer; - in the water at the bottom of the sea or lake; - at the surface of the sea or lake, and below any ice; - at the point of emergence of methane into the atmosphere. An evaluation of a number of possible techniques for dealing with various situations will be presented. This evaluation considers the effectiveness of large-scale deployment of the techniques, used singly or in combination, to reduce the risk of a methane excursion causing abrupt climate change.
12035912 Park, H. (JAMSTEC, Yokosuka, Japan) and Kim, Y. Influences of permafrost reduction on eco-hydrological processes in the terrestrial Arctic regions [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0387, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
The terrestrial Arctic regions have been experienced a set of various changes due to climatic changes and human activities. The significant changes include increased vegetation biomass, permafrost reduction, early snowmelt, etc. Among them, the permafrost reduction caused by the Arctic warming is sequentially linked to eco-hydrological processes (e.g. vegetation production, evapotranspiration). A land surface model CHANGE (Park et al., 2011) had been applied to the terrestrial regions of the Arctic over 60 years (i.e., 1948 to 2006), then it was examined the influence of permafrost dynamics on net primary production (NPP) and evapotranspiration (ET) at basin scale for the major Arctic watersheds. The analysis indicated that the Arctic warming triggered fast soil thawing in the spring and caused deeper active layer depth in summer. The increased active layer depth produced higher soil moisture amount as thawing soil ice content, which significantly contributed to higher ET. A higher significance was also found between the active layer depth and NPP; the deeper active layer depth enhanced NPP, which does imply that the higher soil moisture caused by the active layer depth augmented NPP. These relationships were stronger in Lena watershed covered entirely by continuous permafrost than other watersheds. These results also address the potential impacts of permafrost dynamics on eco-hydrological processes under the future climatic changes.
12035915 Pastick, N. (U. S. Geological Survey, Sioux Falls, SD); Wylie, B. K.; Minsley, B. J.; Jorgenson, T. T.; Ji, L.; Walvoord, M. A.; Smith, B. D.; Abraham, J. D. and Rose, Joshua. Using remote sensing and ancillary data to extend airborne electromagnetic resistivity surveys for regional permafrost interpretation [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0390, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Permafrost has a significant impact on high latitude ecosystems and is spatially heterogeneous. However, only generalized maps of permafrost extent are available. Due to its impacts on subsurface hydrology, lake water levels, vegetation communities, and surface soil deformations, understanding the spatial extents and depth of permafrost are critical. Electrical resistivity increases dramatically as a soil freezes and can be used as a proxy for permafrost presence particularly if the underlying soils and geologic characteristics are understood. An airborne electromagnetic survey (AEM) was conducted over a portion of the Yukon Flats ecoregion in central Alaska with measurements taken in both reconnaissance lines and contiguous block area coverage. The AEM was flown in June 2010 and subsurface resistivity models were derived by inverting the AEM data. Landsat TM at-sensor reflectance, thermal, and spectral index data from late August to early September 2008, Digital Elevation Models (DEM) and derivatives, and other ancillary data were used in a regression tree model to predict near surface electrical resistivity at the 0-1 m and the 0-2.6 m depth intervals. AEM locations from homogenous landsat 90 m by 90 m windows were randomly separated into a training set for model development (n=8,848) and an impendent test data set (n=988) for model accuracy assessment. Model development and independent test accuracies for 0-1 m electric resistivity had training and test R2 values of 0.90 and 0.87, respectively, and for the 0-2.6 m electric resistivity training and test R2 values were also 0.90 and 0.87, respectively, which indicated accurate prediction models. Important variables for stratifying the various piecewise regressions were elevation and averaged 2000-2008 ecosystem performance anomalies. Important independent variables used in the multiple regression equations were the Normalized Difference Infrared Index (NDII), NDII7 (NDII using band 7), soil moisture mapped from landsat, and the Normalized Difference Water Index (NDWI) using band 7. The regression tree models were applied to a 6-scene landsat mosaic and ancillary data to make estimates of electrical resistivity at 0-1 m and 0-2.6 m depths for the entirety of Yukon Flats. Further studies will assess relationships between mapped surface resistivity and depth to permafrost measured in the field.
12035928 Pearce, A. R. (University of Vermont, Rubenstein School, Burlington, VT); Rastetter, E. B. and Bowden, W. Breck. Biogeochemical modeling of tundra recovery following thermal erosion of permafrost [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0403, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
We simulate the biogeochemical recovery of tundra from a thermal erosion disturbance using the Multiple Element Limitation model (MEL) and compare model results with soil organic matter and nutrient chemistry measurements collected across a chronosequence of thermal erosion features. Thermal erosion of permafrost initially depletes the tundra of much of its vegetation and shallow soil organic matter. However, several decades later, there is often little distinguishing these scars from the surrounding undisturbed tundra. As thermal erosion features become more abundant on the arctic landscape, we desire to understand how the pools of carbon and nutrients rebuild after these disturbances. MEL is a plot-scale, process-based model that optimizes the acquisition of eight resources (light, water, CO2, PO4, NH4, NO3, DON and N-fixation) by vegetation based on how much of each is required and the effort needed to acquire it. Model output includes pool sizes of carbon, nitrogen and phosphorus in vegetation, litter, young soil organic matter and old soil organic matter and the fluxes among these pools over time. This calibration of MEL, operating on a daily timestep, was created with published data collected at or near the Toolik Field Station (Toolik Lake, AK, USA) from moist acidic tussock tundra sites. We corroborate our calibration with data from plot manipulations (N and P fertilization, greenhouse, and shade house) performed as part of the NSF Arctic LTER project. The initial conditions for the recovery simulations reflect post-failure observations of some of the variation in soil organic matter, and soil and water nutrient chemistry. With sufficient nutrients from residual soil or supplied in soil water from upslope, the model indicates that vegetation can recover within several decades, but recovery of C and nutrients lost from soils may take hundreds of years.
12035979 Rees, E. V. (Lawrence Berkeley National Laboratory, Earth Sciences Division, Berkeley, CA); Nakagawa, S. and Kneafsey, T. J. Seismic property changes in methane gas hydrate bearing sediments during geomechanical testing [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41B-0804, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Geomechanical properties of methane hydrate bearing sediments can impact oil and gas well stability and production performance of hydrate-bearing reservoirs in permafrost regions. Methane hydrate stability in permafrost environments occurs at lower pressures than those of deep sea deposits. Consequently, changes in temperature conditions that occur during hydrocarbon exploration can have a larger impact on methane hydrate stability than in deep sea fields. In recent years, the understanding of the geomechanical properties of hydrate bearing sediment has advanced significantly. However, geophysical signatures of the changes occurring within the sediment undergoing mechanical changes and failure (which are necessary for remote detection and monitoring of the well and reservoir) are not well understood, primarily because of limited available experimental and field data. We conducted a series of triaxial compression tests on methane-hydrate bearing sediment samples in an X-ray transparent triaxial test cell. The cell can apply high pressures under controlled temperatures (5MPa and 2°C were our typical test parameters). This capability allows us to conduct experiments under the realistic temperature, pressure, and chemical conditions of a hydrate reservoir, which is important for studying the behavior of hydrate bearing sediments subjected to changes in the reservoir environment. The cell is also capable of propagating 6-to-12 kHz compression and torsion waves along the sample axis during the test, due to a piezoelectric source and receiver embedded in the top and bottom loading pedestals. Methane hydrate was first synthesized inside a sediment pack under isotropic stress, after which additional stress was applied to bring the sample to failure. Concurrently, seismic velocities of the sample were monitored throughout the process. Before and after the experiment, X-ray CT images were taken to examine the heterogeneity of hydrate distribution within an intact sample and the distribution of fractures and shear/localization bands in a failed sample. In this presentation, we will discuss the results of these experiments including the changes in seismic signatures during sediment failure and the recovery of seismic signatures within hydrate bearing sediments over 24 hours after failure. In addition, we will also show the effect of dissociation rate on the strength of sediments when the sediment is brought to failure by hydrate dissociation rather than by mechanical loading.
12035922 Regmi, P. (University of Alaska Fairbanks, Geophysical Institute, Fairbanks, AK); Grosse, G.; Jones, M. C.; Jones, B. and Walter Anthony, K. Potential application of TERRASAR-X satellite data for discriminating age of drained thermokarst lake basins on the Seward Peninsula, Alaska [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0397, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Drained thermokarst lake basins (DTLBs) are important indicators of permafrost and thermokarst lake dynamics in polar lowlands with ice-rich permafrost. They accumulate significant amounts of soil organic carbon in the form of peat which is of interest to understanding climate change feedbacks with thermokarst dynamics. However, understanding the temporal and spatial dynamics of DTLBs requires substantial geological, cryolithological, and geochronological ground work in remote regions. Application of remote sensing methods to map DTLBs and their properties is a critical component in upscaling such field results to larger regions. Previous studies have demonstrated potential use of optical remote sensing data to map DTLBs as well as classify their relative age relying on relationships of land surface properties to post drainage succession in vegetation, soils, and permafrost aggradation. In this study, we tested the application of X-band Synthetic Aperture Radar (SAR) data of the German TerraSAR-X satellite with 3 m spatial resolution for determining the time since lake drainage (or drained basin age) for a set of DTLBs located in the ice-rich permafrost region of the northern Seward Peninsula, Alaska. Six stripmap HH polarization images covering the study region of approx. 3801 sq. km were acquired at different dates within the growing season period (July-September) of 2009. A Landsat-5 TM image acquired in July 2009 was also used to aid in the understanding of vegetation patterns in drained basins. We used a set of radiocarbon-dated peat cores from 14 basins ranging in age from 250 to 9000 years before present as well as 57 basins that were observed draining with aerial and satellite image time series within the recent decades to compare TerraSAR-X data with basin age. First for the set of young basins, results show that it is not possible to discriminate the age of DTLBs that drained recently within the last 50 to 60 years by using X-band SAR. However, it was possible to observe seasonal dynamics in these young DTLBs, reflected as increase in backscatter, as the growing season progressed from July to September. For the older DTLBs dated with radiocarbon, a significant logarithmic relationship between basin age and TerraSAR-X backscatter and basin age and Landat-5 TM based Normalized Difference Vegetation Index (NDVI) was observed. The log curves show decreasing trend of backscatter and NDVI as basin age increases. Overall, TerraSAR-X results show the potential application of X-band microwave data to map long-term succession dynamics of DTLBs, which are characterized by post-drainage changes in vegetation, hydrological characteristics, permafrost aggradation, ground ice accumulation, and localized frost heave.
12035949 Rowland, J. C. (Los Alamos National Laboratory, Department of Earth & Environmental Sciences, Los Alamos, NM); Gangodagamage, C.; Wilson, C. J.; Prancevic, Jeff P.; Brumby, S. P.; Marsh, Philip and Crosby, B. T. Scaling laws in Arctic permafrost river basins; statistical signature in transition [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41C-0424, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
The Arctic landscape has been shown to be fundamentally different from the temperate landscape in many ways. Long winters and cold temperatures have led to the development of permafrost, perennially frozen ground, that controls geomorphic processes and the structure of the Arctic landscape. Climate warming is causing changes in permafrost and the active layer (the seasonally thawed surface layer) that is driving an increase in thermal erosion including thermokarst (collapsed soil), retrogressive thaw slumps, and gullies. These geomorphic anomalies in the arctic landscapes have not been well quantified, even though some of the landscape geomorphic and hydrologic characteristics and changes are detectable by our existing sensor networks. We currently lack understanding of the fundamental fluvio-thermal-erosional processes that underpin Arctic landscape structure and form, which limits our ability to develop models to predict the landscape response to current and future climate change. In this work, we seek a unified framework that can explain why permafrost landscapes are different from temperate landscapes. We use high resolution LIDAR data to analyze arctic geomorphic processes at a scale of less than a 1 m and demonstrate our ability to quantify the fundamental difference in the arctic landscape. We first simulate the arctic hillslopes from a stochastic space-filling network and demonstrate that the flow-path convergent properties of arctic landscape can be effectively captured from this simple model, where the simple model represents a landscape flowpath arrangement on a relatively impervious frozen soil layer. Further, we use a novel data processing algorithm to analyze landscape attributes such as slope, curvature, flow-accumulation, elevation-drops and other geomorphic properties, and show that the pattern of diffusion and advection dominated soil transport processes (diffusion/advection regime transition) in the arctic landscape is substantially different from the pattern in temperate landscapes. Our results suggest that Arctic landscapes are characterized by relatively undissected, long planar hillslopes, which convey sediment to quasi-fluvial valleys through long (~1 km) flow-paths. Further, we also document that broad planar hillslopes abruptly converge, forcing rapid subsurface flow accumulation at channel heads. This topographic characteristic can successfully be used to explain the position of erosion features. Finally we estimate the landscape model parameters for the arctic landscape that can be successfully used to model development and validation purposes.
12035941 Sarrazin, Denis (Laval University, Centre for Northern Studies, Quebec City, QC, Canada) and Allard, Michel. Monitoring of thermal contraction cracking in ice wedge polygons, Bylot Island, Nunavut, Canada [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41C-0416, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Ice wedge polygon networks which result from repeated thermal contraction cracking are among the most prominent periglacial features in terrain underlain by continuous permafrost. It has been thoroughly documented that ice-rich frozen soils are affected by thermal contraction when submitted to deep winter cold temperatures, giving way to the opening of networks of cracks. Over the years, the repeated filling of the cracks with surface water in early summer builds up the ice-wedges that delineate tundra polygons. We precisely monitored the timing of cracking and the rates of enlarging and narrowing of well-developed polygonal frost cracks over six years in the Qarlikturvik valley on Bylot Island (N73°09.028' W80°00.242'). Specially designed extension meters were deployed perpendicular to 8 polygon troughs in 2 distinct networks separated by a distance of 1700 m. A preliminary analysis of the data shows that cracks open abruptly but constantly in December. They enlarge in January up to an average of 12 mm in width. The cracks expand more slowly after and reach their maximum width in March. They narrow by the end of the winter with warming temperatures but they stay open at about half of their maximum width for several weeks in May-June. Some observed closing events tend to be abrupt and non-linear. The data were correlated with atmospheric and ground thermal regime data acquired by 5 automated stations during this period. This study brings new information on the atmospheric and geothermal conditions leading to thermal contraction cracking in these ice rich polygon networks.
12036019 Schaefer, Kevin M. (University of Colorado at Boulder, National Snow and Ice Data Center, Boulder, CO); Zhang, T.; Bruhwiler, Lori; Barrett, A. P. and Li, Zhuxiao. Can we avoid the permafrost carbon tipping point? [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC42B-01, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
If we reduce fossil fuel emissions and slow the Arctic warming rate, can we delay or even avoid the permafrost carbon tipping point? Permafrost currently contains about 1466 Gt of carbon frozen during or since the last ice age. The permafrost carbon tipping point occurs when the release of carbon from thawing permafrost overpowers enhanced uptake due to warmer temperatures. The tipping point indicates when the Arctic irreversibly changes from a carbon sink to a source relative to the atmosphere and marks the start of the Permafrost Carbon Feedback. The tipping point is irreversible because once the carbon thaws and decays into the atmosphere, there is no way to put the carbon back into the permafrost. Projections based on the A1B IPCC scenario indicate that the PCF tipping point will occur between 2020 and 2030, with a total of 190±64 Gt of carbon released into the atmosphere by 2300. We ran a series of model projections out to 2300 based on the A1B scenario, but capped emissions at various levels, each representing a different overall Arctic warming. We present the area of permafrost lost, the permafrost carbon tipping point, and total permafrost carbon flux as a function of Arctic temperature increase. We show the maximum allowed Arctic temperature increase before initiating the permafrost carbon feedback.
12035969 Shakhova, N. E. (University of Alaska Fairbanks, Fairbanks, AK); Semiletov, Igor P.; Salyuk, A.; Stubbs, C.; Kosmach, D. and Gustafsson, Orjan. Ebullition-driven fluxes of methane from shallow hot spots suggest significant under-estimation of annual emission from the East Siberian Arctic shelf [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41B-0794, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
The high-latitude, shallow ESAS has been alternately subaerial and inundated with seawater during glacial and interglacial periods respectively. Subaerial conditions foster the formation of permafrost and associated hydrate deposits whereas inundation with relatively warm seawater destabilizes the permafrost and hydrates. Our measurements of CH4 in 1994-2000 and 2003-2010 over ESAS demonstrate the system to be in a destabilization period. First estimates of ESAS methane emissions indicated the current atmospheric budget, which arises from gradual diffusion and ebullition, was on par with estimates of methane emissions from the entire World Ocean (~8 Tg-CH4). Large transient emissions remained to be assessed; yet initial data suggested that component could increase significantly annual emissions. New data obtained in 2008-2010 show that contribution of ebullition-driven CH4 fluxes from shallow hot spots alone could multiply previously reported annual emission from the entire ESAS.
12035914 Smith, B. D. (U. S. Geological Survey, Lakewood, CO); Walvoord, M. A.; Wylie, B. K.; Voss, C. I.; Pastick, N.; Minsley, B. J.; Jepsen, S. M.; Jorgenson, T. T.; Cannia, J. C.; Abraham, J. D. and Anderson, L. New perspectives of permafrost distribution and its influence on groundwater flow and ecosystem performance for the Yukon Flats area, northern Alaska [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0389, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Permafrost is a predominant physical feature of the planet's Arctic and sub-Arctic regions and a major consideration that impacts climate processes, ecosystem function, water resources, and infrastructure engineering. The U.S. Geological Survey has conducted hydrological, geophysical, and geological studies of the Yukon Flats area within the discontinuous permafrost region of Interior Alaska. This is an area of low topographic relief that is populated with numerous streams, lakes and the braided meandering Yukon River with broad gravel-filled channels. Lake sediments and geological archives contain preserved sedimentary records of landscape changes in ecosystems, climate, and groundwater at decade-to-century and millennial time scales. The near-surface geology consists of unconsolidated Pliocene lacustrine silts and clays overlain by late Pleistocene and Holocene alluvial gravels and eolian deposits including extensive loess uplands and dunes. Remotely sensed data for the area from a variety of sensors provide information that is used for both static image interpretations and dynamic process modeling. An airborne electromagnetic survey (AEM) carried out in June of 2010 covered a large area (~1,800 line-km) with widely spaced reconnaissance lines and a 10 by 30 km block near Ft. Yukon. The AEM survey data was inverted to produce resistivity as a function of depth along the flight lines. The resistivity depth sections map the presence or absence of permafrost both laterally and with depth, as well as variations in subsurface lithology. The resulting depth images provide a unique detailed view of the subsurface that has previously only been conceptualized. One application of the remotely sensed data is to extrapolate the AEM data and interpretation between flight lines. Model development and independent test accuracies for 0-1 m electrical resistivity had training and test R2 values of 0.90 and 0.87 indicating accurate prediction models. Groundwater modeling of the Yukon Flats area for an assumed permafrost thaw sequence indicates regional groundwater flow patterns and fluxes to be highly sensitive to changes in permafrost distribution near the transition from continuous to discontinuous permafrost. AEM interpretation helps to define groundwater pathways through unfrozen zones, pathways that may control observed and future climate-change-driven changes in the state of surface waters. Modeling suggests that as permafrost degrades, the component of groundwater flow from sub-permafrost layers discharging to surface water bodies becomes increasingly important. Modeling of the hydrogeologic history of lake basins, improving groundwater models, more detailed geophysical depth section interpretation, and remote sensing analysis will improve the understanding of the relative roles of permafrost, climate, and the causal mechanisms behind widespread surface water and ecosystem changes on the landscape.
12035986 Soliman, A. S. (University of Waterloo, Interdisciplinary Centre for Climate Change, Waterloo, ON, Canada); Duguay, C. R.; Hachem, S. and Royer, Alain. ESA DUE Permafrost; developing uncertainty indices of operational LST products for the modeling community [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41B-0812, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Land Surface Temperature (LST) has been identified as an important remote sensing derived parameter to be used as an input in spatially distributed permafrost models. Operational LST products have recently been made available for the pan-Arctic domain (above 50 degrees North) through ESA's DUE Permafrost project website (URL: http://www.ipf.tuwien.ac.at/permafrost/). The products provide continuous and systematic LST estimates at a 25 km grid size on weekly, monthly and annually time steps. Quantifying uncertainty in these LST products is important to the modeling community (permafrost and climate). More so as satellite-derived LSTs from thermal infrared sensors are for clear sky conditions, which deviate from the "true" (all-sky) LST values. This difference should relate to the distribution of cloudy days within the week or the month of interest for such products, assuming the robustness of the cloud masks and LST retrieval algorithm(s). Three indices are proposed to quantify gaps due to the presence of clouds: a) ratio of observation count between day and night acquisitions, b) total observation count, and c) standard deviation of daily observations count. These indices can provide uncertainty ranges when weekly, monthly or annual LST averages are calculated, prior to integration into permafrost models. In this study, we quantified the difference in LST averages caused by the exclusion of cloudy days compared to North American Regional Reanalysis (NARR) LST estimates and LST derived from passive microwave imager data (SSM/I F13) which is available for all-sky conditions. We tested uncertainty indices derived from missing data to detect the magnitude of differences. Daily LSTs were derived over the entire pan-Arctic at 25 km grid size from MODIS Aqua and Terra Level 2 V5 data (MYD11L2.5 and MOD11L2.5). The daily pan-Arctic product was used to identify cloudy days on a half-daily basis (6 am to 6 pm and 6 pm to 6 am of the next day) and calculate the uncertainty indices for weekly and monthly LST products for two years (2009 and 2010). Daily zero-height air temperatures (equivalent to LST) from NARR and LST from SSM/I were interpolated and aggregated to LST monthly averages with two versions, namely clear-sky and all-sky (including cloudy days). LST estimates from MODIS were compared to LST NARR to evaluate the error generated by excluding cloudy days. Uncertainty indices were tested statistically to explain the magnitude of the differences between MODIS and reanalysis. This presentation will: a) discuss the spatial distribution of LST differences in reference to classes of the Circum-Arctic map of permafrost, and b) discuss the implications of the findings for deriving freezing and thawing indices from available MODIS-derived LST products.
12035938 Stephani, E. (University of Alaska Fairbanks, Institute of Northern Engineering, Fairbanks, AK); Kanevskiy, M. Z.; Fortier, Daniel; Shur, Y.; Jorgenson, T. T.; Dillon, Matthew and Bray, M. Yedomas in Alaska; evolution of ice-rich landscapes in a changing climate [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41C-0413, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Yedomas (Ice complexes) have developed on lands that remained unglaciated during the Late-Pleistocene. Ground exposure to cold climate allowed large syngenetic ice wedges to form typically in fine-grained, organic-rich, and ice-rich enclosing sediments, resulting in particularly ice-rich and thick sequences. Changing climate since has triggered geomorphological changes of these ice-rich landscapes and now contemporary climate conditions generally favour their degradation. Yedoma remnants have been observed in areas of Alaska including in the northern part of Seward Peninsula and Iktilik River area where we studied their metrics, cryostratigraphy, soil properties, and their degradation processes. Understanding the dynamic of this particular periglacial landscape and determining its properties is essential for modeling its future evolution in a changing climate. At our three study sites, presence of typical geomorphological features and cryostratigraphic units revealed information on the landscape evolution since deposition of these ice-rich strata. A Yedoma deposit in the northern part of Seward Peninsula comprised ice wedges at least 36 m-deep. The enclosing sediment was characterized by an ice-rich cryofacies of coarse silt with microlenticular cryostructure and abundant fine rootlets. The intermediate layer, a typical extremely ice-rich layer located below the active layer, was observed above the Yedoma deposit in areas less affected by thermo-degradation. In the thermo-degraded areas characterized by an irregular terrain surface, the intermediate layer was replaced by the generally ice-poor taberal cryofacies which corresponds to a deposit that was formerly ice-rich, thawed, drained, and eventually refrozen. Yedoma remnants in their contemporary degrading state can be recognized with their abundant thermokarst lakes, drained lake basins, and drainage gullies. Thermokarst lakes can be particularly deep because of the considerable amount of ground ice that can melt. Catastrophic lake drainage often occurs along ice-wedge polygons connecting lakes. At our sites, baidjarakhs (thermokarst mounds) and taberal cryofacies was found over the remaining Yedoma deposit in the drained lake basin (alas) and in the drainage gullies. Coalescence of numerous drained lake basins eventually forms alas valleys and ultimately alas plains which represent the most advance stage of Yedoma degradation. Other processes of Yedoma degradation observed included thermo-erosion of massive ice in outcrops along river bank. At the Iktilik River site, the outcrops of large ice-wedges with baidjaraks at their toe were protected from thermo-erosion. However, areas of massive ice 30 m-high exposed to flowing water had niche formed at their toe where ice had melted, such as it is commonly observed along the Beaufort Sea coast, and sets of deep cracks of several meters developed within few days. The ice-wedge block collapsed in the river, melted and disappeared in less than 24h. It can be expected that the exposure protected by baidjarakhs will be exposed to such catastrophic degradation event once the baidjarakhs have been eroded by the river.
12035929 Strauss, Jens (Alfred-Wegener-Institute, Periglacial Research, Potsdam, Germany); Schirrmeister, Lutz and Wetterich, Sebastian. Fossil organic carbon in Siberian yedoma and thermokarst deposits [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0404, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
During the late Quaternary, a large pool of organic carbon accumulated in the ice-rich syngenetic frozen deposits and soils preserved in the arctic and subarctic permafrost zone. Because of the potential release of organic carbon from degrading permafrost, the organic-matter (OM) inventory in Yedoma deposits and its degradation features are relevant to current concerns about the effects of global warming. In this context, it is essential to improve the understanding permafrost-stored OM composition and availability. The objective of this study is to develop an approach of OM quantification in frozen deposits including OM quality estimation. We analyzed OM characteristics like total organic carbon content, stable carbon isotopes and carbon-nitrogen ratios. Moreover, lipid biomarkers (alkanes, fatty acids and glycerol dialkyl glycerol tetraether) and sediment parameters like grain size and bulk density of Yedoma and thermokarst deposits exposed at Duvanny Yar (lower Kolyma River, Siberia) and the west coast of Buor Khaya Peninsula (Laptev Sea, Siberia) were studied. With the biomarker approach it is possible to distinguish deposits which were accumulated and frozen during the Pleistocene and Holocene. Biomarker indices, like the compound specific index, average chain length and tetraether characteristics supply feasible results for past permafrost environments. Late Pleistocene biomarker records indicate cold conditions during the growth/summer period for the late Pleistocene and generally low degradation of the stored OM. In contrast, Holocene thermokarst deposits indicate warmer conditions. The averaged volumetric OM content of the studied Yedoma and thermokarst deposits are greater than 10 kg/m3 and do not exceed 30 kg/m3. Given that Yedoma deposits accumulated at relatively fast rates and at low temperatures, the OM underwent a short time of decomposition before it was incorporated into a permanently-frozen state. Consequently, such deposits contain a labile carbon inventory as reflected by the biomarker results. We conclude that Yedoma with its degradation features at Duvanny Yar and Buor Khaya contain an organic-carbon inventory which is lower than in other published Yedoma profiles. Nevertheless, these deposits contain a significant carbon pool because of low OM decomposition rates and for this reason a potential high risk for its activation and release under warming conditions.
12035995 Tong, J. (University of California at Irvine, Irvine, CA); Velicogna, Isabella; Zhang, T. and Kimball, John S. Increase in groundwater storage in discontinuous permafrost areas in Eurasia and impact on vegetation productivity [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41C-0836, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
We use monthly measurements of time-variable gravity from the GRACE (Gravity Recovery and Climate Experiment) satellite mission to determine the increase in terrestrial water storage (TWS) in Eurasia, during the period 2002-2011. We compare monthly TWS from GRACE with TWS from time series of precipitation (P) minus evapo-transpiration (ET) from ERA-Interim re-analysis and observational river discharge (R) in the Lena, Yenisei and Ob river basins. We find an excellent agreement between the two time series of TWS. If we account for a negative bias in the average annual precipitation during the analyzed period, we effectively close the terrestrial water budget. From this comparison, we attribute both the increase in R and in TWS to an increase in P. In the Lena river basin the TWS increase is dominated by a large signal in an area of discontinuous permafrost. We attribute the observed signal to an increase in groundwater storage of 68±19 cubic km or to surface water recharging the ground water through areas not underlain by permafrost, while changes in active layer thickness have likely less impact. These TWS changes will have a significant impact on the terrestrial hydrology of the region, including increased baseflow and alteration of seasonal runoff. We also analyze the temporal and spatial correlation between TWS and Normalized Difference Vegetation Index (NDVI) and Net Primary Production (NPP) from MODIS. We show how the correlation changes within water rich and water limited areas as well as in function of different land cover types. We find that vegetation productivity in the Lena river basin is mainly controlled by temperature constraints rather than moisture availability, while in the Ob river basin it is mainly controlled by water limitation.
12035988 Voltersen, Michael (Friedrich-Schiller-University Jena, Department of Earth Observation, Jena, Germany); Urban, Marcel; Pöcking, Stefan; Hese, Sören and Schmullius, C. C. High resolution monitoring of lake object structure changes in Arctic permafrost regions [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41C-0819, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
The natural ecosystem of arctic permafrost regions underlies changes caused by climate driven variations in freeze/thaw processes. As a result in many locations degradation of permafrost could have been observed during the last decades, which leads to the transformation of existing landforms like changes in terrain (thermokarst effects), hydrology and vegetation. In order to quantify the variance of thermokarst water bodies, historical and recent high spatial resolution optical remote sensing data are utilized to identify fine scaled changes according to their size, density, extent and distribution. This study presents an object oriented monitoring strategy for lake object structure changes using multi-temporal remote sensing imagery as part of ESAs Data User Element (DUE) Permafrost. Spatial growth and shifting effects of thermokarst lakes are quantified by classifying satellite imagery of the photo-reconnaissance satellite systems of the "Key Hole"- series (e. g. Corona) from the 1960s and recently recorded RapidEye data. Four different test sites located in the far east of Russia (Yakutsk and Lena river delta) and North America (North Slope/Alaska and Beaufort Sea Region/Canada) are analyzed. The co-registration of the CORONA and Rapideye imagery is done by the LCPC (Lake Center Point Correction), which guarantees a high geometric fit of the derived lake objects. Specific lake object characteristics such as object shape, area, elliptical fit, direction and density are extracted in order to generate a structural water body change product. The synergetic analysis of the data provides statements about spatio-temporal lake transformation within this time period. The presented methodological approach provides a robust and transferable concept for large scale change mapping and is important to quantify changes under potential permafrost degradation conditions.
12035913 Walvoord, M. A. (U. S. Geological Survey, Lakewood, CO); Voss, C. I. and Wellman, T. P. Influence of permafrost distribution on regional groundwater flow in the Yukon Flats Basin, Alaska [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0388, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Degradation of permafrost in interior Alaska is expected to have significant impacts on the routing of water above and below the land surface. This study attempts to elucidate modes of regional groundwater flow for various patterns of permafrost to assess the hydrologic control of permafrost presence and to evaluate potential hydrologic consequences of permafrost degradation. The Yukon Flats Basin, a large (118,340 sq km) sub-basin within the Yukon River Basin in Alaska, provides the basis for this regional groundwater flow modeling investigation. Model simulations that represent an assumed permafrost thaw sequence via diminishing permafrost spatial coverage and volume exhibit the following trends: 1) increased groundwater discharge to rivers, consistent with historical trends in baseflow observations in the Yukon River Basin, 2) increased potential for overall recharge and overall groundwater flow, 3) increased extent of groundwater discharge in the flats, and 4) decreased ratio of supra-permafrost to sub-permafrost groundwater in river baseflow. Such trends have implications for the chemical composition and residence time of riverine exports, the status of lakes and wetlands influenced by groundwater, seasonal river ice thickness, and seasonal stream temperatures. Model results identify the classically-defined transition from continuous to discontinuous permafrost coverage at 90% to be within a relatively narrow range of the permafrost distribution spectrum that is particularly vulnerable to hydrologic change. Major hydrologic changes are predicted near this transition with relatively minor changes in permafrost distribution. For example, the model-predicted proportion of stream baseflow derived from lateral flow in the supra-permafrost zone decreases from 52% to 17% as permafrost coverage decreases from 95% and 89%, respectively. Presently, the Yukon Flats Basin is coarsely mapped as spanning the critical transition between continuous and discontinuous permafrost, thus underscoring the need for improved characterization of permafrost and other hydrogeologic information in the study area via geophysical techniques, remote sensing, and ground truthed observations.
12035975 Whalley, B. (Sheffield University, Department of Geography, Sheffield, United Kingdom). The mysterious case of the vanishing permafrost; Gruben rock glacier, Switzerland [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract GC41B-0800, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
As glaciers are losing ice volume in the Alps, as elsewhere, so is mountain permafrost. This has been recognised by increased rockfall activity from steep mountain faces. The presence of ice-rich permafrost and reduction of volume is more difficult to detect where the slope angle is lower than that of free rock faces. The lagged response makes it difficult to detect melting and any consequent surface lowering. Rock glaciers have been viewed as indicative of the result of flow of ice-rich permafrost and thus indicators of mat of <1.5°C. Although the 'permafrost' model has been contested, the alternative, 'glacier core' model does not deny that permafrost conditions can exist for some rock glaciers exhibiting ice cores and thus differentiation is difficult just by viewing or imaging the surface topographic feature. The rock glacier at Grubengletscher (Wallis, Switzerland) has been studied since the 1970s and has been used as an exemplar of rock glaciers that indicate mountain permafrost. The site has been examined over several years because of potential water flooding (jokulhlaups) affecting a village in the valley. Published mapping of the feature shows the portion mapped as 'rock glacier' (= permafrost) has been increasingly reduced over the last 20 years. The upstream area has been indicated to be glacier ice-cored as small thermokarst lakes have formed. Field examination of the whole feature shows that small glacier ice exposures exist even in the 'rock glacier'. This view of 'hidden glacier ice' is confirmed by examining topographic maps from about 1850 CE where the whole of the basin is shown as being glacier covered. The debris covering and protecting the glacier-derived ice must date from after this (Late Little Ice Age) period. Other recent examples of exposed glacier ice below debris can also be seen at mountain locations as diverse as Turkey and Alaska as well as from the length of the Rockies. The conclusion is that care must be taken in using rock glaciers anywhere as necessarily indicating permafrost, whether present day features or mapped as paleo-permafrost indicators used in climatic reconstructions. As global temperatures increase, continued observation at rock glacier sites should confirm or deny the general presence of glacier ice cores or actual permafrost-bound ice.
12035945 Williams, K. K. (Buffalo State College, Department of Earth Sciences, Buffalo, NY); Haltigin, Timothy and Pollard, Wayne H. Ground penetrating radar detection of ice wedge geometry; implications for climate change monitoring [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41C-0420, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Polygonal features in the Canadian High Arctic are found in many areas, have diverse appearances, and occur in a variety of surface materials. As part of a larger project using geophysical methods to study ice wedge depth, width, and thickness, ground penetrating radar (GPR) data were collected across polygonal surface features on Devon Island. As with polygonal features in other locations on Earth, not all of the features studied on Devon Island contain subsurface ice, however polygons with notable surface troughs did contain fairly large ice wedges. The polygons in this study were formed in fine sediments near Thomas Lee Inlet east of the Haughton impact crater, and GPR data were collected at 200 MHz and 400 MHz using the GSSI, Inc. SIR-3000 system. Although both GPR and capacity-coupled resistivity (CCR) data were collected, the CCR data may have been adversely affected by melt water at the base of the active layer. Conversely, the GPR data show the thickness of the active layer, the width of the top of the ice wedge, and other subsurface stratigraphic features very well. Locations and widths of wedge ice were confirmed by augering and trenching to the tops of the ice wedges. GPR data clearly delineate the edges of the tops of ice wedges. Interestingly, the GPR-determined edges correlate with surface tensional cracks that appear to be related to subsidence above the wedge. It is possible that this subsidence is caused by an increase in active layer thickness and downward melting of the ice wedge in response to increasing temperatures over several years or more. If this is the case, small amounts of surface subsidence above ice wedges could be a useful indicator of past and current climate change in Arctic regions. To address this possibility, a broader study is proposed.
12035930 Wilson, C. J. (Los Alamos National Laboratory, Department of Earth and Environmental Sciences, Los Alamos, NM); Travis, B. J. and Ossola, I. Predicting CO2 and CH4 emissions from the active layer in response to climate warming [abstr.]: in AGU 2011 fall meeting, American Geophysical Union Fall Meeting, 2011, Abstract C41B-0405, December 2011. Meeting: American Geophysical Union 2011 fall meeting, Dec. 5-9, 2011, San Francisco, CA.
Permafrost resides beneath 25% of the land in the northern hemisphere. Observations and models suggest that permafrost is warming and thawing, the active layer is thickening, and previously frozen old soil carbon is being converted and released as CH4 and CO2. GHG release amounts and rates are poorly constrained, as is the ratio between CH4 vs CO2. This ratio is important because CH4 is significantly more powerful as a greenhouse gas than is CO2. The arctic is projected to experience more precipitation, and perhaps more thermokarst lake formation, both of which could result in wetter conditions that favor CH4 production. At the same time, permafrost degradation could lead to thermal erosion and other landscape processes that enhance drainage and drier soil conditions that favor CO2 production. As the community continues to develop techniques to identify how the soil moisture status of the Arctic landscape will evolve, we are developing a model to assess how a range of soil moisture conditions, from very wet to very dry, will drive changes in GHG emissions as warming continues. Our numerical model (named ARCHY) is designed to simulate coupled surface and subsurface processes in freezing environments. It can operate in 1-D, 2-D or 3-D, is time-dependent, and includes vertical and lateral water and vapor and gas movement in heterogeneous soils and between soils and atmosphere, snow cover, heat transport, solar irradiation, precipitation, temperature, small scale topography, change of phase between water, ice and vapor, and three spatially distributed species of microbes including aerobes, anaerobes, and methanotrophs. A number of comparisons to data, including a set of soil temperatures and CO2 and CH4 emissions vs time at Toolik lake, as well as experiments on unsaturated flow in a domain with a freezing boundary, provide validation of the coupled thermal, hydrologic and microbiological processes in our model. We are using this calibrated model to contrast gas emissions from thawing permafrost over a range of soil moisture conditions, from a warmer but drier soil to a warmer and wetter soil column. The simulations spin up the soil column from present conditions to a warmer climate over several years. Significantly more CH4 evolution occurs in a wet, anoxic column compared to the present day climate, while a drier, oxic column shows more CO2 evolution but less CH4. Amounts and rates of emissions can be quantified and related to soil moisture contents and climate temperature increases.
12031321 Esch, John M. (Michigan Department of Environmental Quality, Office of the Geological Survey, Lansing, MI). Michigan bedrock topography, glacial drift thickness and bedrock outcrop maps [abstr.]: in Geological Society of America, Northeastern Section, 46th annual meeting; Geological Society of America, North-Central Section, 45th annual meeting, Abstracts with Programs - Geological Society of America, 43(1), p. 56, March 2011. Meeting: Geological Society of America, Northeastern Section, 46th annual meeting; Geological Society of America, North-Central Section, 45th annual meeting, March 20-22, 2011, Pittsburgh, PA.
Few studies exist concerning the thickness of the glacial drift, the underlying bedrock surface or the distribution of outcrops in Michigan. Newly assembled bedrock topography, glacial-drift thickness and bedrock outcrop maps for Michigan show a very irregular bedrock surface which underlies the thickest glacial drift on land in North America. The bedrock topography map was constructed using data from water, oil and gas, and mineral wells, bedrock shorelines and outcrops, county soil data, waterfalls, and quarries. The glacial drift thickness map was constructed by subtracting the bedrock surface from a National Elevation Dataset digital elevation model. The bedrock surface consists of high relief resistant bedrock highlands and cuestas as well as lowlands and deep bedrock valleys. Bedrock valleys in places show well defined drainage networks with tributaries while others show long linear parallel valleys. The bedrock surface has been sculpted by numerous paleo-river channels cut into the bedrock during the numerous glacial ice advances over the last 2.5 million years. Others appear to have been cut in preglacial times. Several prominent resistant bedrock cuestas occur, some of which extend into Lake Huron and across southern Ontario Canada. The bedrock surface strongly influenced glacial lobe movement, ice-marginal positions, and interlobate positions. The Upper Peninsula is characterized by two distinct bedrock surface regions. In the western Upper Peninsula, Precambrian, crystalline bedrock forms large, high relief bedrock uplands. This contrasts with the generally low elevations and relief on the bedrock surface in the eastern Upper Peninsula, which consists of softer Paleozoic sedimentary rocks and subtle cuestas. Drift averages 270 feet thick and as much as 1,320 feet thick in the Lower Peninsula. Drift in the Upper Peninsula is generally less than 50 feet (with many more outcrops), but is locally thicker overlying bedrock valleys. The land surface topography in the Upper Peninsula generally mimics the underlying bedrock topography. These maps will assist geologists in understanding lobe dynamics, potential glacial aquifers in bedrock valleys, migration pathways, in seismic data processing for oil and gas exploration, bedrock geology mapping, aggregate, mineral and ground-water exploration.
12031504 O'Brien, Rachel (Allegheny College, Department of Geology, Meadville, PA); Song, Mingyuan and Shaffer, Christopher. Regional surficial mapping in northwestern Pennsylvania [abstr.]: in Geological Society of America, Northeastern Section, 46th annual meeting; Geological Society of America, North-Central Section, 45th annual meeting, Abstracts with Programs - Geological Society of America, 43(1), p. 86, 4 ref., March 2011. Meeting: Geological Society of America, Northeastern Section, 46th annual meeting; Geological Society of America, North-Central Section, 45th annual meeting, March 20-22, 2011, Pittsburgh, PA.
Northwestern Pennsylvania contains a thick sequence of glacial deposits that represent multiple advances and retreats of Quaternary ice sheets. In spite of their significant economic and natural resource value, these regional unconsolidated materials remain poorly described and mapped. Here, we present the synthesis of our regional compilation of published and new work towards a regional aquifer resource map. We have digitized extant county sediment thickness maps (Richards et al., 1987; Shiner and Gallaher, 1979; Schiner and Kimmel, 1976) along with a regional surficial geology map (Shepps et al., 1959). Surface topography, soil maps, and more than 3,000 borehole measurements of sediment thickness (from water and oil/gas well records) have also been added to our geospatial database. Faculty-student research efforts have created field maps to cover previously undocumented portions of the region. Based on sediment thickness, surficial geology, soil association, landscape position, and slope, we have compiled these collective resources to create a regional map of aquifer potential for northwestern Pennsylvania. References Richards, D.B., H.J. McCoy, and J.T. Gallaher, 1987, Groundwater resources of Erie County, Pennsylvania: Pennsylvania Geological Survey, 4th ser., Water Resource Report 62, 101 p., 2 plates. 1:62,500. Schiner, G.R., and G.E. Kimmel, 1976. Geology and groundwater resources of northern Mercer County: Pennsylvania Geological Survey, 4th ser., Water Resource Report 33, 136 p, 2 plates. 1:24,000. Schiner, G.R., and J.T. Gallaher, 1979, Geology and groundwater resources of western Crawford County, Pennsylvania: Pennsylvania Geological Survey, 4th ser., Water Resources Report 46, 103 p, 3 plates. 1:50,000. Shepps, V.C., G.W. White, J.B. Droste, and R.F. Sitler, 1959. Glacial geology of northwestern Pennsylvania: Pennsylvania Geological Survey, General Geology Report 32, 59 p., 1 plate. 1:125,000.
12032714 Valentino, Joshua (State University of New York at Oswego, Department of Earth and Environmental Sciences, Oswego, NY); Inners, Jon D. and Lazore, Melanie B. Joint and bedding controls on waterfall morphology and periglacial mass wasting, Ricketts Glen, NE PA [abstr.]: in Geological Society of America, Northeastern Section, 46th annual meeting; Geological Society of America, North-Central Section, 45th annual meeting, Abstracts with Programs - Geological Society of America, 43(1), p. 129, March 2011. Meeting: Geological Society of America, Northeastern Section, 46th annual meeting; Geological Society of America, North-Central Section, 45th annual meeting, March 20-22, 2011, Pittsburgh, PA.
At Ricketts Glen on the glaciated Allegheny Front in NE Pennsylvania, Kitchen Creek has carved out 22 waterfalls in gently N-dipping Upper Devonian and Mississippian strata. The sedimentary sequence consists, in descending order, of the Mississippian Pocono Fm., gray, conglomeritic sandstone; the Mississippian-Devonian Huntley Mountain Fm. (HMF), mostly gray, crossbedded, fine-grained sandstone; and the Upper Devonian Duncannon Mbr. of the Catskill Fm., fining-upward cycles of gray sandstone to red shale. All waterfalls are in the HMF and Duncannon. Mass wasting and ledge retreat are evident in the uppermost HMF and basal Pocono, the latter forming the caprock of the Front escarpment. Bedrock joints, bedding, and crossbedding dictate the configuration of the individual falls. Two subvertical joint sets are dominant in all bedrock units: ENE-E and N-S. Small variations in joint orientation are associated with the occurrence of high joint density zones and splays. 20 falls are dominantly controlled by the E-W joints where the N-S joints are conduits for water flow, and two falls, Mohawk and Shawnee, are controlled by the N-S joints. In addition, the prevalent crossbedding of the HMF and Duncannon redirects the water and shapes the falls either through smooth ramps or alternating bedding dips. Bedding and jointing control the periglacial mass wasting of the Pocono and HMF, where large blocks are displaced and moved down the slope of the Front. Three styles controlled by the E-W joints occur: listric, where blocks have tilted upslope; toppling, where blocks are tilted downslope; and creep, where blocks have moved out from the ledges with little or no tilt. The first two are particularly characteristic of the uppermost ledge of the HMF, while the third occurs in the main E-W ledge of the basal Pocono. Dip of some listric and toppled blocks is up to 40°. Creep in the Pocono is evident as far as 40 m N of the face of the escarpment, the E-W joints showing through the soil cover as shallow, elongate depressions. Really spectacular is the creep of Pocono blocks at Midway Crevasse, a mass of jumbled blocks, which has moved out 30 m S of the main ledge. Some "shove" by the late Wisconsinan glacier, which reached its NW-trending border 10 mi SW of the Glens, may also have been involved in movement of these blocks.
12033459 Akimov, M. P. (Northeastern Federal University, Institute of Mathematics and Computer Science, Yakutsk, Russian Federation). Prognozirovaniye vliyaniya podzemnogo polimernogo truboprovoda teplosnabzheniya na vechnomerzlyye grunty [Prediction of underground heat-supplying polymeric pipeline influence on permafrost]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 221-224 (English sum.), illus. incl. table, 3 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033006 Battler, M. M. (University of Western Ontario, Department of Earth Sciences, London, ON, Canada); Osinski, G. R.; Lim, D. S. S.; Davila, A. F.; Michel, F. A.; Craig, M. A.; Izawa, M. R. M.; Leoni, L.; Slater, G. F.; Fairén, A. G. and Starratt, S. W. The Golden Deposit in the Canadian Arctic as an analogue for jarosite deposition at Meridiani Planum and Mawrth Vallis, Mars: in Lunar and planetary science conference XLII; papers presented to the Forty-second lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 42, Abstract 2759, illus., 6 ref., 2011. Meeting: Forty-second lunar and planetary science conference, March 7-11, 2011, Woodlands, TX. Accessed on Dec. 7, 2011.
URL: http://www.lpi.usra.edu/meetings/lpsc2011/pdf/2759.pdf
12033460 Bayasan, R. M. (InterHeat Pipeline, Moscow, Russian Federation); Bayasan, T. V.; Pustovoyt, G. P.; Golubin, S. I. and Tseyeva, A. N. Innovatsionnye tekhnicheskiye resheniya po termostabilizatsii mnogolethemerzlykh porod pri stroitel'stve v kriolitozone [Innovative engineering solutions for thermal stabilization of permafrost]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 225-230 (English sum.), illus., 5 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033445 Bing Hui (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Lanzhou, China) and Zhao Shuping. Study on the failure mechanism of roadbed with saline soil under cyclical freeze-thaw: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 138-143 (Russian sum.), illus. incl. 5 tables, 12 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12032563 Brooks, G. R., editor. Summary of a workshop on Light-weight coring techniques and equipment used by Northern Canada Division, Geological Survey of Canada: Open-File Report - Geological Survey of Canada, Rep. No. 6746, 18 p., tables, 1 ref., 2011. WWW. Meeting: Workshop on Light-weight coring techniques and equipment used by Northern Canada Division, Geological Survey of Canada, Nov. 15, 2010, Canada. Accessed on March 14, 2012.
This Open File is the record of a workshop on light-weight coring techniques and equipment used by staff of Geological Survey of Canada-Northern Canada (GSC-NC) Division on November 15, 2010. It contains an overview of the rationale behind the workshop, abstracts and pdf files of the nine presentations, and a list of current, in-house, light-weight coring equipment (as of December 1, 2010).
URL: http://geopub.nrcan.gc.ca/moreinfo_e.php?id=288036
12032931 Centeno, J. D. (Universidad Complutense de Madrid, Departmento de Geodinámica, Madrid, Spain) and de Pablo, Miguel Angel. Possible evidences of ice dynamics in the putative glaciers at the lower NW flank of Hecates Tholus Volcano, Mars: in Lunar and planetary science conference XLII; papers presented to the Forty-second lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 42, Abstract 1031, illus., 12 ref., 2011. Meeting: Forty-second lunar and planetary science conference, March 7-11, 2011, Woodlands, TX. Accessed on Nov. 21, 2011.
URL: http://www.lpi.usra.edu/meetings/lpsc2011/pdf/1031.pdf
12033495 Chizhuk, A. L. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation). Ekologicheskaya otsenka soderzhaniya mikroelementov v donnykh otlozheniyakh ozer g. Yakutska [Ecological analysis of trace elements concentration in lake sediments in Yakutsk City]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 459-462 (English sum.), illus. incl. 2 tables, 6 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033498 Chzhan, R. V. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation); Spektor, V. B.; Alekseyeva, O. I.; Torgovkin, Ya. I.; Shestakova, A. A.; Ivanova, L. D. and Spektor, V. V. Inzhenerno-geologicheskaya karta RS(Ya) i prilegayushchikh territoriy m-ba 1:2,500,000 [Engineering-geological map of Sakha (Yakutia) and neighboring areas at scale 1:2,500,000]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 18-23 (English sum.), 25 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033425 Chzhan, R. V. (Russian Academy of Sciences, Siberian Division, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation). Uchastiye instituta merzlotovedeniya im. P. I. Mel'nikova (SO RAN) v nauchnom soprovozhdenii megaproyektov v Vostochnoy Sibiri [Participation of the P. Melnikov Permafrost Institute (Russian Academy of Sciences, Siberian Division) in regional programs in east Siberia]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 13-17 (English sum.), illus., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12034802 Clifford, S. M. (Lunar and Planetary Institute, Houston, TX); Lasue, J.; Le Gall, A. and Heggy, E. The response of Martian ground ice to burial by a volatile-poor mantle; potential implications for the volatile evolution of the Medusae Fossae Formation: in Lunar and planetary science conference XLII; papers presented to the Forty-second lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 42, Paper no. 2142, illus., 5 ref., 2011. Meeting: Forty-second lunar and planetary science conference, March 7-11, 2011, Woodlands, TX. Accessed on Jan. 13, 2012.
URL: http://www.lpi.usra.edu/meetings/lpsc2011/pdf/2142.pdf
12033446 Croll, James G. A. (University College London, London, United Kingdom). Thermal ratchet uplift buckling and periglacial morphologies: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 144-149 (Russian sum.), illus., 18 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12034803 Dinwiddie, C. L. (Southwest Research Institute, Geosciences and Engineering Division, San Antonio, TX); McGinnis, R. N.; Stillman, D. E.; Bjella, K. L. and Grimm, R. E. Geophysical Mars analog studies of multiphase water in the Great Kobuk sand dunes, northwestern Alaska: in Lunar and planetary science conference XLII; papers presented to the Forty-second lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 42, Paper no. 2501, illus. incl. sects., sketch maps, 16 ref., 2011. Meeting: Forty-second lunar and planetary science conference, March 7-11, 2011, Woodlands, TX. Accessed on Jan. 13, 2012.
URL: http://www.lpi.usra.edu/meetings/lpsc2011/pdf/2501.pdf
12033470 Dolgikh, G. M. (FundamentStroyArkos Enterprise, Tyumen, Russian Federation); Okunev, S. N.; Strizhkov, S. N. and Dolgikh, S. N. Opyt proyektirovaniya i ekspluatatsii sistemy termostabilizatsii gruntov plotiny na r. Irelyakh [Practice of application of thermal stabilization technology for earth dams on the Irelyakh River]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 288-291 (English sum.), illus., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033469 Dolgikh, G. M. (FundamentStroyArkos Enterprise, Tyumen, Russian Federation); Okunev, S. N.; Zakharova, V. N.; Maramygina, M. S. and Dolgikh, S. N. Prognoznyye raschety merzlotnoy protivofil'tratsionnoy zavesy plotiny Vilyuyskoy GES-3 ispol'zovaniyem kollektornykh SOU [Numerical analysis and predictions for permafrost infiltration-preventing barrier at Vilyuy GES-3 hydroelectric power plant and seasonal use of ground-cooling technology]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 280-283 (English sum.), illus., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033474 Dong Xianfu (Administration of the Qinghai Railroad, Xining, China); Sun Liping; Chen Ji and Sheng Yu. Research on the thermal stability of frozen soil embankment in the Chaidaer-Muli Railway: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 312-318 (Russian sum.), illus., 15 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12034807 Dundas, Colin M. (University of Arizona, Lunar and Planetary Laboratory, Tucson, AZ); Byrne, Shane and McEwen, Alfred S. Modeling development of Martian sublimation thermokarst landforms: in Lunar and planetary science conference XLII; papers presented to the Forty-second lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 42, Paper no. 2527, illus., 14 ref., 2011. Meeting: Forty-second lunar and planetary science conference, March 7-11, 2011, Woodlands, TX. Accessed on Jan. 13, 2012.
URL: http://www.lpi.usra.edu/meetings/lpsc2011/pdf/2527.pdf
12033430 Fedorov, D. K. (B. Vedeneyev Research Institute of Hydraulic Engineering, Saint Petersburg, Russian Federation) and Krivonogova, N. F. Kriogennoye pucheniye gruntov primenitel'no k gibkim ograzhdayushchim konstruktsiyam [Frost heaving of grounds interacting with flexible barrier structures]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 53-58 (English sum.), illus. incl. 2 tables, 9 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033493 Fedorova, L. L. (Russian Academy of Sciences, I. Chersky Northern Mining Institute, Yakutsk, Russian Federation) and Sokolov, K. O. Otsenka stepeni gotovnosti poligona k otrabotke po dannym georadiolokatsii [Preliminary assessment of planned excavation sites based on surveys with ground-penetrating radar]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 450-454 (English sum.), illus., 3 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033475 Feng Wenjie (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, State Key Laboratory of Frozen Engineering, Lanzhou, China); Ma Wei; Sun Zhizhong; Li Guoyu; Yu Wenbing and Zheng Jianfeng. Radiation effect analysis of the awning measure on the embankment slope field test in cold regions: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 319-325 (Russian sum.), illus., 15 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033486 Galanin, A. A. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation). Opasnyye merzlotno-gravitatsionnye protsessy v rayone mestorozhdeniya Dvoynoye (Chukotskiy AO); rezul'taty distantsionnogo izucheniya [Hazardous permafrost-related and gravity-driven processes in the Dvoynoye Deposit area (Chukchi Peninsula); data from remote sensing]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 410-416 (English sum.), illus., 5 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033444 Gavril'yev, R. I. (Russian Academy of Sciences, Siberian Division, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation). Raschet temperatrnykh voln v dvykhsloynoy srede kriolitozony pri izmenyayushcheysya srednesutochnoy temperature vozdukha [Numerical analysis of thermal regime of two-layer permafrost under changing diurnal temperatures]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 132-137 (English sum.), illus., 6 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033485 Gavril'yev, R. I. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation). Teplofizicheskiye svoystva otlozheniy Yenisey-Khatangskogo progiba i yego yuzhnogo obramleniya [Thermophysical properties of sediments in the Yenisei-Khatanga Trough and its southern outer zone]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 404-409 (English sum.), illus. incl. 4 tables, 2 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033447 Ghazavi, Mahmoud (K. N. Toosi University of Technology, Civil Engineering Department, Tehran, Iran) and Roustaei, Mahya. Laboratory evaluation of the behavior of a geotextile reinforces clay on freeze-thaw cycles: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 150-154 (Russian sum.), illus. incl. table, 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033490 Grib, N. N. (Northeastern Federal University, Technical Institute, Neryungri, Russian Federation); Syasko, A. A.; Nikitin, V. M.; Kachayev, A. V. and Kuznetsov, P. U. Izucheniye ekzogennykh protsessov geofizicheskimi metodami pri vybore ploshchadki pod stroitel'stvo shpalopropitochnogo zavoda OAO AK "Zheleznyye dorogi Yakutii" [Application of geophysical methods for engineering geological analysis of a construction site intended for a production facility of the Yakutia Railway Company]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 433-438 (English sum.), illus., 3 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033461 Guliy, S. A. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Magadan, Russian Federation) and Rozhelevskiy, I. K. Monitoring gruntov osnovaniy fundamentov Ledovogo dvortsa v g. Magadane [Monitoring of ground under foundation of Magadan ice sports center]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 231-236 (English sum.), illus. incl. 4 tables, 5 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033462 Guliy, S. A. (Russian Academy Sciences, P. Melnikov Permafrost Institute, Magadan, Russian Federation). Analiz paboty plotiny, pereshedshey s merzlogo na talyy tip eksplyatatsii (na primere plotiny ArGREC na r. Myaundzha) [Performance of earth dams during transition from freezing to thawing (Arkagalinskaya hydroelectric power plant on the Myaundzha River as an example)]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 237-242 (English sum.), illus., 5 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033438 Gur'yanov, I. Ye. (Russian Academy of Sciences, Siberian Division, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation). Nesushchaya sposobnost' vechnomerzlogo osnovaniya kak funktsiya tipa fundamenta [Dependence of permafrost bearing capacity on foundation type]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 96-103 (English sum.), illus. incl. 4 tables, 3 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033439 Gur'yanov, I. Ye. (Russian Academy of Sciences, Siberian Division, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation). Obshchaya metodika naturnogo opredeleniya nesushchey sposobnosti svaynykh fundamentov v vechnomerzlykh gruntakh [General approach to analysis of pile foundation bearing capacity in permafrost]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 104-109 (English sum.), 3 tables, 5 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12034805 Haltigin, T. W. (McGill University, Department of Geography, Montreal, QC, Canada); Pollard, W. H. and Dutilleul, P. Statistical evidence of polygonal terrain self-organization on Earth and Mars: in Lunar and planetary science conference XLII; papers presented to the Forty-second lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 42, Paper no. 1622, illus., 10 ref., 2011. Meeting: Forty-second lunar and planetary science conference, March 7-11, 2011, Woodlands, TX. Accessed on Jan. 13, 2012.
URL: http://www.lpi.usra.edu/meetings/lpsc2011/pdf/1622.pdf
12033432 Isayev, O. N. (Reseach Institute of Foundations and Underground Construction, Moscow, Russian Federation). Identifikatsiya talogo i merzlogo sostoyaniy gruntov metodom staticheskogo zondirovaniya [Identification of thawed and frozen grounds with use of static sounding]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 63-67 (English sum.), illus., 6 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033433 Isayev, O. N. (Research Institute of Foundations and Underground Construction, Moscow, Russian Federation). Metody ispytaniya merzlykh gruntov staticheskim zondirovaniem [Methods of static sounding applied to frozen ground testing]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 68-73 (English sum.), illus., 9 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033487 Ivanova, L. D. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation) and Pavlova, N. A. Agressivnost' nadmerzlotnykh i nadmerzlotno-mezhmerzlotnykh vod Yakutii k stroitel'nym materialam i konstruktsiyam [Impact of supra- and inter-permafrost ground waters on construction materials and structures in Yakutia]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 417-421 (English sum.), illus. incl. table, sketch map, 4 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033443 Kaymonov, M. V. (Russian Academy of Sciences, Institute of Mining in the North, Yakutsk, Russian Federation); Panishev, S. V. and Yermakov, S. A. Modelirovaniye temperaturnogo rezhima vzorvannykh mnogoletnemerzlykh gornykh porod [Modeling of blasted rock thermal regime in permafrost zone]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 127-131 (English sum.), illus., 7 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033437 Konovalov, A. A. (Russian Academy of Sciences, Institute of Northern Regions Development, Tyumen, Russian Federation). Fazovyye perekhody i dolgovechnost' merzlogo grunta [Phase transitions and durability of frozen ground]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 90-95 (English sum.), illus. incl. table, 7 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033448 Kozlowski, Tomasz (Kielce University of Technology, Kielce, Poland). Low temperature freezing of water adsorbed on clays in view of DSC and MDSC experiments: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 155-160 (Russian sum.), illus. incl. 3 tables, 10 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033471 Kudryavtsev, S. (Far Eastern Transportation University, Khabarovsk, Russian Federation) and Shtokolov, A. Povtornoye ispol'zovaniye metallicheskikh svay v vechnomerzlykh gruntakh na Chayandinskom neftegazokondensatnom mestorozhdenii [Repeated use of metal pile foundations in permafrost of Chayanda oil and gas field]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 292-295 (English sum.), illus., 4 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033472 Kutvitskaya, N. B. (Fundamentproyekt, Moscow, Russian Federation) and Semenova, N. P. Osobennosti uplotneniya gruntov deyatel'nogo sloya trambovaniyem v usloviyakh rasprostraneniya vechnomerzlykh gruntov [Hardening of soil active layer by tamping in permafrost zone]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 296-299 (English sum.), illus., 7 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033434 Kuzmin, G. P. (Russian Academy of Sciences, Siberian Division, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation) and Panin, V. N. Metod opredeleniya pucheniya grunta [A method for analysis of soil frost heaving]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 74-77 (English sum.), 2 tables, 2 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033431 Kuzmin, G. P. (Russian Academy of Sciences, Siberian Division, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation). Vzaimosvyaz' pokazateley fizicheskikh svoystv gruntov [Interrelations between soil physical properties]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 59-62 (English sum.), illus., 4 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12031718 Lee, Yoo Kyung (Korea Polar Research Institute, Division of Life Sciences, South Korea); Kim, Ok-Sun; Kim, Hyemin; Hong, Soon Gyu; Chun, Jongsik and Lee, Bang Yong. Microbial diversity of active layer soil from the Canadian high Arctic: in Lunar and planetary science conference XLII; papers presented to the forty-second lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 42, Abstract 1357, 2 ref., 2011. Meeting: Forty-second lunar and planetary science conference, March 7-11, 2011, Woodlands, TX. Accessed on Sept. 12, 2011.
URL: http://www.lpi.usra.edu/meetings/lpsc2011/pdf/1357.pdf
12033428 Ma Wei (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Lanzhou, China); Fang Lili and Qi Jilin. Methodology of study on freeze-thaw cycling induced changes in engineering properties of soils: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 38-43, illus. incl. table, 26 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033496 Makarov, V. N. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation) and Torgovkin, N. V. Inzhenerno-geokhimicheskaya kharakteristika gruntov g. Neryungri [Engineering-geochemical characteristics of soils in Neryungri]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 463-468 (English sum.), 8 tables, 3 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033494 Makarov, V. N. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation). Zasolennost' gruntov na territorii goroda Yakutska [Salinization of frozen grounds in Yakutsk City]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 455-458 (English sum.), illus. incl. 2 tables, 6 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12034983 Mangold, Nicholas (Université Nantes, Laboratoire de Planétologie et Géodynamique de Nantes, Nantes, France). Post-early Mars fluvial landforms on mid-latitude impact ejecta: in Lunar and planetary science conference XLII; papers presented to the Forty-second lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 42, Abstract 1378, illus., 18 ref., 2011. Meeting: Forty-second lunar and planetary science conference, March 7-11, 2011, Woodlands, TX. Accessed on Sept. 14, 2011.
URL: http://www.lpi.usra.edu/meetings/lpsc2011/pdf/1378.pdf
12033463 Mel'nikov, A. Ye. (Northeastern Federal University, Neryungri Department, Neryungri, Russian Federation) and Pavlov, S. S. Problema otsenki intensivnosti razrusheniya gruntov, slagayushchikh zemlyanuyu nasyp', pod vozdeystviem vyvetrivaniya (na primere Amuro-Yakutskoy zheleznodorozhnoy magistrali, uchastok Tommot-Kerdem) [Assessment of embankment destruction caused by frost heaving (example from the Tommot-Kerdem segment of the Amur-Yakutsk Railroad)]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 243-245 (English sum.), 6 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12032950 Molina, A. (University of Alcalá, Centro de Astrobiologia, Madrid, Spain); de Pablo, M. A. and Ramos, M. Implications of MER Mini-TES surficial and atmospherical temperatures evolution during a year on Gusev Crater, Mars: in Lunar and planetary science conference XLII; papers presented to the Forty-second lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 42, Abstract 1116, illus. incl. 1 table, 5 ref., 2011. Meeting: Forty-second lunar and planetary science conference, March 7-11, 2011, Woodlands, TX. Accessed on Nov. 21, 2011.
URL: http://www.lpi.usra.edu/meetings/lpsc2011/pdf/1116.pdf
12033429 Niu Fujun (Cold and Arid Regions Environmental and Engineering Research Institute, Lanzhou, China); Liu Hua; Lin Zhanju and Lu Jiahao. Physical changes of five types of rock in the Qinghai-Tibet Plateau under freeze-thaw cycles: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 45-50 (Russian sum.), illus. incl. 3 tables, 11 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12031715 Pavlov, A. A. (NASA, Goddard Space Flight Center, Greenbelt, MD); Caffrey, M.; Getty, S. and Johnson, C. S. Formation of liquid water in the shallow subsurface under simulated Martian conditions: in Lunar and planetary science conference XLII; papers presented to the forty-second lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 42, Abstract 2480, illus., 2011. Meeting: Forty-second lunar and planetary science conference, March 7-11, 2011, Woodlands, TX. Accessed on Sept. 12, 2011.
URL: http://www.lpi.usra.edu/meetings/lpsc2011/pdf/2480.pdf
12033455 Petrukhin, V. P. (N. Gersevanov Research Institute for Foundations and Underground Construction, Moscow, Russian Federation); Shulyat'yev, O. A.; Bondarenko, G. I.; Bezvolev, S. G.; Mozgacheva, O. A.; Samoletov, Y. Y.; Beletskiy, E. V. and Romashko, G. B. Opyt proyektirovaniya GOK v usloviyakh seysmokriolitozony [Practice of coal mining planning in seismically active permafrost zone]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 197-203 (English sum.), illus., 5 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033427 Popenko, F. Ye. (Geotechnology, Yakutsk, Russian Federation). Tekhicheskaya melioratsiya slabykh gruntov kriolitozony pri stroitel'stve na seysmoopasnykh territoriyakh [Engineering melioration of weak soils in permafrost zone during construction in seismic regions]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 33-37 (English sum.), 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033440 Popov, V. I. (Russian Academy of Sciences, Institute of Mining in the North, Yakutsk, Russian Federation). Vliyaniye znakoperemennykh temperaturnykh vozdeystviy na protsess moroznogo vyvetrivaniya [Effect of temperature variations on frost weathering]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 110-114 (English sum.), illus., 6 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033464 Poznarkova, S. V. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Igarka Station, Igarka, Russian Federation) and Zepalov, F. N. Otsenka 20-letney ekspluatatsii fundamenta-obolochki v g. Igarka [Analysis of pile foundation stability in the town of Igarka for the past 20 years]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 246-251 (English sum.), illus., 4 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033473 Rastegayev, I. K. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation); Serdobov, V. B. and Morozov, R. V. Issledovaniye effekta "plavaniya" rabochego oborudovaniya rykhliteley staticheskogo deystviya v merzlom grunte [Analysis of static soil ripper operation in permafrost]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 300-305 (English sum.), illus., 5 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033426 Rastegayev, I. K. (Russian Academy of Sciences, Siberian Division, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation) and Velikin, S. A. Sostoyaniye i perspektivy svaynogo fundamentostroyeniya v kriozone Zemli v svyazi s potepleniyem klimata [Construction of pile foundations in permafrost zone with regard to global warming; current state and future perspectives]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 25-32, 8 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033442 Razumov, S. O. (Russian Academy of Sciences, Siberian Division, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation). Modelirovaniye kriogennykh geologicheskikh protsessov v izmenyayushchikhsya prirodnykh i tekhnogennykh usloviyakh [Modeling of cryogenic geological processes under changing natural conditions and impact of human activity]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 121-126 (English sum.), illus., 2 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033449 Roustaei, Mahya (Qazvin Islamic Azad University, Civil Engineering Department, Qazvin, Iran); Ghazavi, Mahmoud and Aghabarati, Hassan. Strength characteristics of tire-clay mixtures in freeze-thaw cycles: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 161-166 (Russian sum.), illus. incl. table, 29 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033491 Savvin, D. V. (Russian Academy of Sciences, I. Cherskiy Northern Institute of Mining, Yakutsk, Russian Federation); Fedorova, L. L. and Omelyanenko, A. V. Issledovaniye metodom georadiolokatsii izmeneniya kriogennogo sostoyaniya gruntov pri tekhnogennom vozdeystvii [Application of ground-penetrating radar for analysis of change in permafrost under influence of human activity]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 439-443 (English sum.), illus., 3 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12034806 Séjourné, Antoine (Université Paris Sud XI, Laboratoire Interactions et Dynamique des Environnements de Surface, Orsay, France); Costard, F.; Fedorov, A.; Gargani, J.; Soare, R. J. and Marmo, C. Thermokarst degradation of potential ice-wedge polygons inside scalloped depressions in Utopia Planitia, Mars: in Lunar and planetary science conference XLII; papers presented to the Forty-second lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 42, Paper no. 1904, illus., 12 ref., 2011. Meeting: Forty-second lunar and planetary science conference, March 7-11, 2011, Woodlands, TX. Accessed on Jan. 13, 2012.
URL: http://www.lpi.usra.edu/meetings/lpsc2011/pdf/1904.pdf
12033483 Shepelev, V. V. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation) and Chzhan, T. P. O bor'be s podtopleniyem na urbanizirovannykh territoriyakh kriolitozony [Urban flood control in a permafrost zone]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 379-383 (English sum.), illus., 6 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033466 Shesternev, D. M. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation) and Litovko, A. V. Geokriologicheskiye problemy ekspluatatsii uchastka zheleznoy dorogi AYaM "Berkakit-Tommot" [Geocryological aspects of Amur-Yakutsk Railroad exploitation in its Berkakit-Tommot segment]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 261-266 (English sum.), illus., 5 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033467 Shesternev, D. M. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation); Shender, N. I.; Varlamov, S. P.; Litovko, A. V. and Sleptsova, Yu. G. Geokriologicheskiye usloviya i ikh izmeneniya pri stroitel'stve zheleznoy dorogi AYaM na uchastke "ledovogo kompleksa" [Geocryological conditions and their changes from construction of the Amur-Yakutsk Railroad in its most complex "ice wedge" segment]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 267-272 (English sum.), illus., 5 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033465 Shesternev, D. M. (Russan Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation). Osnovnye printsipy organizatsii geokriologicheskogo monitoringa lineynykh sooruzheniy (na primere zheleznoy dorogi Berkakit-Tommot-Yakutsk) [Basic principles of geocryological monitoring of transportation systems (Berkakit-Tommot-Yakutsk Railroad as example)]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 252-260 (English sum.), illus. incl. 2 tables, 11 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033476 Shi Feng (Beijing Jiaotong University, School of Civil Engineering, Beijing, China); Fang Jianhong; Liu Jiankun and Peng Liyun. Experimental study on the mechanism of thawing settlement under dynamic loading in 109th National Highway: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 331-336 (Russian sum.), illus. incl. table, 5 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033488 Sivtzev, A. I. (Russian Academy of Sciences, Siberian Division, Institute of Oil and Gas, Yakutsk, Russian Federation) and Rozhin, I. I. Obosnovaniye potentsial'nykh skopleniy gaza podmerzlotno-gidratnym flyuidouporom [Potential accumulation of gas hydrates in sub-permafrost fluid-proof zone]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 422-428 (English sum.), illus., 7 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033492 Skachkov, Yu. B. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation); Skryabin, P. N. and Varlamov, S. P. Izmeneniya temperatury gruntov sloya godovykh teplooborotov na yakutskom teplobalansovom statsionare za posledniye sorok let [Change of near-surface ground temperature at Yakutsk permafrost observation station during the last 40 years]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 444-449 (English sum.), illus. incl. 2 tables, 8 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033457 Skryabin, P. N. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation). Izmeneniya termicheskogo sostoyaniya gruntov pri tekhnogennykh vozdeystviyakh na severnom uchastke zheleznoy dorogi Tommot-Yakutsk [Changes of frozen ground thermal regime along northern segment of Tommot-Yakutsk Railroad caused by human activity]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 210-214 (English sum.), illus. incl. table, 6 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12034804 Soare, R. J. (Dawson College, Department of Geography, Montreal, QC, Canada); Costard, F. and Pearce, G. Possible pingos and crater-floor periglacial landscapes in northwest Utopia Planitia; a re-assessed hypothesis based on HiRISE imagery: in Lunar and planetary science conference XLII; papers presented to the Forty-second lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 42, Paper no. 1364, illus., 12 ref., 2011. Meeting: Forty-second lunar and planetary science conference, March 7-11, 2011, Woodlands, TX. Accessed on Jan. 13, 2012.
URL: http://www.lpi.usra.edu/meetings/lpsc2011/pdf/1364.pdf
12033441 Sobol', I. S. (Nizhniy Novgorod State University of Architecture and Civil Engineering, Nizhniy Novgorod, Russian Federation) and Khokhlov, D. N. Avtomatizatsiya inzhenernykh raschetov beregopereformirovaniy na vodokhranilishchakh kriolitozony [Automated engineering analysis of reservoir bank transformation in permafrost zone]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 115-120 (English sum.), illus. incl. 3 tables, 3 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033458 Stepanov, A. V. (Russian Academy of Sciences, V. Larionov Institute for Physicotechnical Problems in the North, Novosibirsk, Russian Federation); Rozhin, I. I. and Popenko, F. Ye. Tekhnicheskaya melioratsiya massiva gruntov v osnovanii zdaniya [Geotechnical treatment of frozen ground under foundation]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 215-220 (English sum.), illus. incl. 3 tables, 9 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033484 Struchkova, G. P. (Russian Academy of Sciences, V. Larionov's Institute of Physicotechnical Problems in the North, Yakutsk, Russian Federation); Yefimov, V. M.; Kapitonova, T. A. and Sleptsov, O. I. Vozdeystviye antropogennykyh i tekhnogennykh avariy na ekologicheskuyu bezopasnost' Respubliki Sakha (Yakutiya) [Influence of man-caused accidents on ecological safety in Republic of Sakha (Yakutia)]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 384-388 (English sum.), illus., 5 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12034967 Teodoro, Luís F. A. (NASA, Ames Research Center, Bay Area Environmental Research Institute, Moffett Field, CA); Elphic, Richard C.; Eke, Vincent R.; Roush, Ted L.; Marzo, Giuseppe A.; Brown, Adrian J.; Feldman, William C. and Maurice, Sylvestre. Characterizing the 3-D water distribution on the Mars surface: in Lunar and planetary science conference XLII; papers presented to the Forty-second lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 42, Abstract 2187, illus., 8 ref., 2011. Meeting: Forty-second lunar and planetary science conference, March 7-11, 2011, Woodlands, TX. Accessed on Dec. 1, 2011.
URL: http://www.lpi.usra.edu/meetings/lpsc2011/pdf/2187.pdf
12033435 Urban, A. A. (Russian Academy of Sciences, Siberian Division, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation) and Dorofeyev, I. V. Razvitiye protsessov moroznogo pucheniya i formy yego proyavleniya na primere g. Yakutska [Evolution of frost heaving and its features in Yakutsk City]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 78-82 (English sum.), illus., 5 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033456 Varlamov, S. P. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation); Skryabin, P. N. and Shender, N. I. O teplovom sostoyanii osnovaniy nasypey zheleznoy dorogi Tommot-Kerdem na uchastke rasprostraneniya porod ledovogo kompleksa [Thermal regime of Tommot-Kerdem Railroad's embankment in ground ice-rich permafrost area]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 204-209 (English sum.), illus., 3 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033489 Vasyutich, L. A. (Chita State University, Chita, Russian Federation). Antropogennyye vozdeystviya na kachestvo pit'yevykh vod urbanizirovannykh territoriy yuzhnoy kriolitozony (na primere g. Chity) [Impact of human activity on quality of drinking water in urban areas located near the southern boundary of the permafrost zone (example from Chita City)]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 429-432 (English sum.), 4 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033454 Velikin, S. A. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation); Malyshev, A. V.; Neklyudov, V. V. and Panichev, A. A. K voprosu o sisteme upravleniya merzlotnoy obstanovkoy na inzhenernykh ob"yektakh v kriolitozone [Aspects of permafrost control at engineering structures in the cryolithozone]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 191-196 (English sum.), illus., 1 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033436 Verhoturov, A. G. (Chita State University, Chita, Russian Federation). Opasnyye kriogennyye protsessy v naselennykh punktakh Tsentral'nogo Zabaykal'ya [Hazardous cryogenic processes in populated areas of central Transbaikalia]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 83-89 (English sum.), illus., 7 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033450 Wang Enliang (Heilongjiang Provincial Hydraulic Research Institute, Harbin, China); Sun Jinglu; Gao Zhankun and Chang Junde. Experimental study on monitoring automation technology of freezing depth of seasonal frozen soil: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 167-171 (Russian sum.), illus., 5 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033481 Wang Jiliang (Heilongjiang Cold Region Construction Science Research Institute, Harbin, China) and Zhang Chenxi. Experimental study on bearing capacity of pile foundation in permafrost area: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 364-368 (Russian sum.), illus. incl. 6 tables, 5 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033482 Wang Jiliang (Heilongjiang Cold Region Construction Science Research Institute, Harbin, China) and Zhang Chenxi. Inspection of hydration heat of concrete on permafrost temperature: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 369-372 (Russian sum.), illus., 5 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12031717 Yakovlev, Valeriy (Laboratory of Water Quality "Playa", Kharkov, Ukraine). The hydrolaccoliths of Holden Crater; the possible storage of life traces: in Lunar and planetary science conference XLII; papers presented to the forty-second lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 42, Abstract 1115, illus., 4 ref., 2011. Meeting: Forty-second lunar and planetary science conference, March 7-11, 2011, Woodlands, TX. Accessed on Sept. 12, 2011.
URL: http://www.lpi.usra.edu/meetings/lpsc2011/pdf/1115.pdf
12033477 Yang Chengsong (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, State Key Laboratory of Frozen Soil Engineering, Lanzhou, China); Cheng Guodong; Che Tao and Niu Fujun. The spatial distribution of ground ice and dry density in permafrost region along the Qinghai-Tibet Railway: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 337-342 (Russian sum.), illus., 5 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033478 Yao Xiaoliang (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Lanzhou, China) and Qi Jinlin. Vehicles loading effects on thawing embankment: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 343-348 (Russian sum.), illus. incl. 2 tables, 20 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033497 Yefremov, V. N. (Russian Academy of Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation). Novyye vozmozhnosti izucheniya merzlykh gruntov radioimpedansnym zondirovaniem [New approach to frozen ground analysis based on radiowave impedance sounding]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 469-470 (English sum.), 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033479 Yu Qihao (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, State Key Laboratory of Frozen Soil Engineering, Lanzhou, China); Hu Jun; Qian Jin and You Yanhui. Analysis on the potential problems of constructing a high-grade highway in permafrost regions: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 349-357 (Russian sum.), illus., 47 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033468 Zabolotnik, S. I. (Russian Academy Sciences, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation) and Zabolotnik, P. S. Temperatura gruntov vokrug i pod zdaniyami Yakutskoy TETs [Temperature of frozen ground at the Yakutsk power plant]: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 273-279 (English sum.), illus., 4 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12034808 Zent, A. P. (NASA, Ames Research Center, Moffett Field, CA); Sizemore, H. G. and Rempel, A. W. Ice lens formation and frost heave at the Phoenix landing site: in Lunar and planetary science conference XLII; papers presented to the Forty-second lunar and planetary science conference, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference, 42, Paper no. 2543, illus., 8 ref., 2011. Meeting: Forty-second lunar and planetary science conference, March 7-11, 2011, Woodlands, TX. Accessed on Jan. 13, 2012.
URL: http://www.lpi.usra.edu/meetings/lpsc2011/pdf/2543.pdf
12033424 Zhang, R. V., editor (Russian Academy of Sciences, Siberian Division, P. Melnikov Permafrost Institute, Yakutsk, Russian Federation). Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma [Permafrost engineering; Proceedings of the IX international symposium]: Proceedings - International Symposium on Permafrost Engineering, 9, 470 p., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation. Individual papers are cited separately.
12033451 Zhang Hu (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Lanzhou, China); Zhang Jianming; Liu Shiwei and Su Kai. Pressuremeter test in warm and ice-rich permafrost: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 172-177 (Russian sum.), illus. incl. table, 15 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033452 Zhang Shujuan (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, State Key Laboratory of Frozen Soil Engineering, Lanzhou, China); Sun Zhizhong and Li Shuangyang. Hysteretic energy and temperature behavior of frozen soils under cyclic loading: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 178-183 (Russian sum.), illus. incl. 2 tables, 22 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033480 Zhang Yu (Beijing Jiaotong University, School of Civil Engineering, Beijing, China); Fang Jianhong; Liu Jiankun and Xu Anhua. Field study on reinforcement effects of soil treatment with dynamically formed gravel pier composite foundation in saline soils: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 358-363 (Russian sum.), illus. incl. 2 tables, 13 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12033453 Zhao Shuping (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, State Key Laboratory of Frozen Soil Engineering, Lanzhou, China); Ma Wei; Jiao Guide and Luo Fei. The impact of freeze-thaw cycles on the dynamic characteristics of frozen Qinghai-Tibet clay: in Problemy inzhenernogo merzlotovedeniya; materialy IX mezhdunarodnogo simpoziuma (Zhang, R. V., editor), Proceedings - International Symposium on Permafrost Engineering, 9, p. 184-188 (Russian sum.), illus. incl. table, 15 ref., 2011. Meeting: Problemy inzhenernogo merzlotovedeniya; IX mezhdunarodnyy simpozium, Sept. 3-7, 2011, Mirnyy, Russian Federation.
12028996 Lesovaya, S. (Saint Petersburg State University, Department of Physical Geography and Landscape Planning, St. Petersburg, Russian Federation); Krupskaya, V.; Vigasina, M. and Melchakova, L. V. Weathering and pedogenesis from ultrabasic rocks (dunite-harzburgite complex) in bioclimatic conditions of mountainous tundra, the Polar Urals, Russia [abstr.]: in IMA2010; 20th general meeting of the International Mineralogical Association; abstracts (Zaharia, Luminita, editor; et al.), Acta Mineralogica-Petrographica. Abstract Series, 6, p. 640, 2 ref., 2010. Meeting: 20th general meeting of the International Mineralogical Association, Aug. 21-27, 2010, Budapest, Hungary.
12029007 Mayrhofer, Maria (University of Natural Resources and Applied Life Sciences, Institute of Applied Geology, Vienna, Austria); Wriessnig, Karin and Ottner, F. The influence of clay on site characteristics in the Vienna Forest, Austria [abstr.]: in IMA2010; 20th general meeting of the International Mineralogical Association; abstracts (Zaharia, Luminita, editor; et al.), Acta Mineralogica-Petrographica. Abstract Series, 6, p. 645, 2010. Meeting: 20th general meeting of the International Mineralogical Association, Aug. 21-27, 2010, Budapest, Hungary.
12028967 Motenko, R. G. (Lomonosov Moscow State University, Moscow, Russian Federation); Kuznetsova, E. P.; Vigasina, M. F. and Melchakova, L. V. The influence of allophane and palagonite appearance on the frozen water content in the frozen volcanic ashes [abstr.]: in IMA2010; 20th general meeting of the International Mineralogical Association; abstracts (Zaharia, Luminita, editor; et al.), Acta Mineralogica-Petrographica. Abstract Series, 6, p. 625, 1 table, 3 ref., 2010. Meeting: 20th general meeting of the International Mineralogical Association, Aug. 21-27, 2010, Budapest, Hungary.
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