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2022002463 Chen, Lin (University of Montreal, Department of Geography, Montreal, QC, Canada); Voss, Clifford I.; Fortier, Daniel and McKenzie, Jeffrey M. Surface energy balance of sub-arctic roads with varying snow regimes and properties in permafrost regions: Permafrost and Periglacial Processes, 32(4), p. 681-701, illus. incl. 2 tables, sketch map, 73 ref., December 2021.
Surface energy balance (SEB) strongly influences the thermal state of permafrost, cryohydrological processes, and infrastructure stability. Road construction and snow accumulation affect the energy balance of underlying permafrost. Herein, we use an experimental road section of the Alaska Highway to develop a SEB model to quantify the surface energy components and ground surface temperature (GST) for different land cover types with varying snow regimes and properties. Simulated and measured ground temperatures are in good agreement, and our results show that the quantity of heat entering the embankment center and slope is mainly controlled by net radiation, and less by the sensible heat flux. In spring, lateral heat flux from the embankment center leads to earlier disappearance of snowpack on the embankment slope. In winter, the insulation created by the snow cover on the embankment slope reduces heat loss by a factor of three compared with the embankment center where the snow is plowed. The surface temperature offsets are 5.0°C and 7.8°C for the embankment center and slope, respectively. Furthermore, the heat flux released on the embankment slope exponentially decreases with increasing snow depth, and linearly decreases with earlier snow cover in fall and shorter snow-covered period in spring. Abstract Copyright (2021), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2129
2022002455 Demidov, Vasiliy (Arctic and Antarctic Research Institute, St. Petersburg, Russian Federation); Wetterich, Sebastian; Demidov, Nikita; Schirrmeister, Lutz; Verkulich, Sergey; Koshurnikov, Andrey; Gagarin, Vladimir; Ekaykin, Aleksey; Terekchov, Anton; Veres, Arina and Kozachek, Anna. Pingo drilling reveals sodium-chloride-dominated massive ice in Grondalen, Spitsbergen: Permafrost and Periglacial Processes, 32(4), p. 572-586, illus. incl. 2 tables, sketch map, 51 ref., December 2021.
Drilling of a 21.8-m-deep borehole on top of the 10.5-m-high Nori pingo that stands at 32 m asl in Grondalen Valley (Spitsbergen) revealed a 16.1-m-thick massive ice enclosed by frozen sediments. The hydrochemical compositions of both the massive ice and the sediment extract show a prevalence of Na+ and Cl- ions throughout the core. The upper part of the massive ice (stage A) has low mineralization and shows an isotopically closed-system trend in d18O and dD isotopes decreasing down-core. Stage B exhibits high mineralization and an isotopically semi-open system. The crystallographic structure of Nori pingo's massive ice provides evidence of several large groundwater intrusions that support the defined formation stages. Analysis of local aquifers leads to suggest that the pingo was hydraulically sourced through a local fault zone by low mineralized sodium-bicarbonate groundwater of a Paleogene strata aquifer. This groundwater was enriched by sodium and chloride ions while filtering through marine valley sediments with residual salinity. The comparison between the sodium-chloride-dominated massive ice of the Nori pingo and the sodium-bicarbonate-dominated ice of the adjacent Fili pingo that stands higher up the valley may serve as an indicator for groundwater source patterns of other Nordenskiöld Land pingos. Abstract Copyright (2021), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2124
2022002456 Frappier, Roxanne (University of Ottawa, Department of Geography, Environment and Geomatics, Ottawa, ON, Canada) and Lacelle, Denis. Distribution, morphometry, and ice content of ice-wedge polygons in Tombstone Territorial Park, central Yukon, Canada: Permafrost and Periglacial Processes, 32(4), p. 587-600, illus. incl. 2 tables, sketch map, 55 ref., December 2021.
Investigations of the regional distribution of ice-wedge polygons and wedge-ice volume allow for the assessment of the vulnerability of permafrost landscapes to thaw-induced disturbances and related ecological feedbacks. Ice-wedge polygons have been described in multiple studies in flat terrain and low-gradient hillslopes, but few studies have examined ice-wedge polygons in mountainous terrain. This study investigates the distribution, morphometry, and wedge-ice content of ice-wedge polygons in Tombstone Territorial Park, a mountainous permafrost region in central Yukon. Results show that ice-wedge polygons occupy 2.6% of the park and preferentially develop in woody sedge peat, glaciofluvial, and alluvial deposits along the lower reaches of the Blackstone and East Blackstone rivers on hillslopes ≤&eq;1°. The morphometry of five of six polygonal sites studied showed statistically similar polygon sizes and trough angles, while showing different development stages based on vegetation type, surface wetness, and spatial pattern. The estimation of wedge-ice volumes in the ice-wedge polygons is 8-22% and is comparable to that of other Arctic regions. However, the estimated wedge-ice volume represents a minimum value because older generations of ice wedges are truncated 3-4 m below the surface with no evidence of surface polygons, and the polygonal network can be obscured by slope processes, vegetation, and ice-wedge inactivity. This study provides insights into the application of morphometric and soil parameters for the assessment of ice-wedge polygon distribution and development stages. Abstract Copyright (2021), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2123
2022002453 Kunz, Julius (University of Wuerzburg, Institute of Geography and Geology, Wuerzburg, Germany) and Kneisel, Christof. Three-dimensional investigation of an open- and a closed-system pingo in northwestern Canada: Permafrost and Periglacial Processes, 32(4), p. 541-557, illus. incl. 1 table, sketch maps, 73 ref., December 2021.
The present study presents three-dimensional investigations of a hydrostatic pingo in the Mackenzie Delta region and a hydraulic pingo in the Ogilvie Mountains and contributes to a better understanding about the internal structures of the two pingo types. A combined approach using quasi-three-dimensional electrical resistivity tomography, ground-penetrating radar and frost probing allowed a clear delineation of frozen and unfrozen areas in the subsurface. At the hydrostatic pingo a massive ice core as well as a surrounding talik could be detected, but the location of the ice core and the talik differs from previous published assumptions. In contrast to acknowledged theory, at our site the massive ice core is not located in the center of the pingo but at the western edge, whereas the eastern flank is underlain by a talik, which surrounds the massive ice core. At the hydraulic pingo, the expected internal structure could be confirmed and the pathway of upwelling water could also be detected. The combined approach of the applied methods represents the first known three-dimensional geoelectrical investigation of pingos and provides new insights into the internal structure and architecture of the two different pingo types. The chosen approach allows further conclusions on the formation of these permafrost-affected landforms. Abstract Copyright (2021), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2115
2022002461 Reinosch, Eike (Technische Universität Braunschweig, Institute of Geodesy and Photogrammetry, Germany); Gerke, Markus; Riedel, Björn; Schwalb, Antje; Ye Qinghua and Buckel, Johannes. Rock glacier inventory of the western Nyainqentanglha Range, Tibetan Plateau, supported by InSAR time series and automated classification: Permafrost and Periglacial Processes, 32(4), p. 657-672, illus. incl. 5 tables, sketch maps, 88 ref., December 2021.
The western Nyainqêntanglha Range on the Tibetan Plateau reaches an elevation of 7,162 m and is characterized by an extensive periglacial environment under semi-arid climatic conditions. Rock glaciers play an important part of the water budget in high mountain areas and recent studies suggest that they may even act as climate-resistant water storages. In this study we present the first rock glacier inventory of this region containing 1,433 rock glaciers over an area of 4,622 km. To create the most reliable inventory we combine manually created rock glacier outlines with an automated classification approach. The manual outlines were generated based on surface elevation data, optical satellite imagery and a surface velocity estimation. This estimation was generated via InSAR time series analysis with Sentinel-1 data from 2016 to 2019. Our pixel-based automated classification was able to correctly identify 87.8% of all rock glaciers in the study area at a true positive rate of 69.5%. In total, 65.9% of rock glaciers are classified as transitional with surface velocities of 1-10 cm/yr. In total, 18.5% are classified as active with higher velocities of up to 87 cm/yr. The southern windward side of the mountain range contains more numerous and more active rock glaciers. We attribute this to higher moisture availability supplied by the Indian Monsoon. Abstract Copyright (2021), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2117
2022002462 Rico, Ibai (University of the Basque Country, Department of Geography, Prehistory, and Archaeology, Vitoria-Gasteiz, Spain); Magnin, Florence; López Moreno, Juan Ignacio; Serrano, Enrique; Alonso-González, Esteban; Revuelto, Jesús; Hughes-Allen, Lara and Gómez-Lende, Manuel. First evidence of rock wall permafrost in the Pyrenees (Vignemale Peak, 3,298 m a.s.l., 42°46'16"N/0°08'33"W): Permafrost and Periglacial Processes, 32(4), p. 673-680, illus. incl. 2 tables, sketch map, 37 ref., December 2021.
Permafrost is a relevant component of the Pyrenean high mountains, triggering a wide range of geomorphological cryogenic processes. Although in the past decades there has been an increase in frozen ground studies in the Pyrenees, there are no specific studies about rock wall permafrost, its presence, distribution, thermal regime, or historical evolution. This work combines measured rock surface temperatures (RSTs, from August 2013 to April 2016) along an elevation profile (four sites) on the north facing the rock wall of the Vignemale peak (3,298 m a.s.l., 42°46'16"N/0°08'33"W) and temperature modeling (CryoGRID2) to determine the presence of permafrost and to analyze its evolution since the mid-20th century. Simulations are run with various RST forcings and bedrock properties to account for forcing data uncertainty and varying degrees of rock fracturing. Results reveal that warm permafrost may have existed down to 2,600 m a.s.l. until the early 1980s and that warm permafrost is currently found at »2,800 m a.s.l. and up to 3,000 m a.s.l. Cold (<-2°C) permafrost may exist above 3,100-3,200 m a.s.l. Systematic investigations on rock wall permafrost must be conducted to refine those results in the Pyrenees. The elevation shift in warm permafrost suggests an imminent disappearance of permafrost in the Vignemale peak. Abstract Copyright (2021), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2130
2022002457 Serban, Raul-David (Chinese Academy of Sciences, Northwest Institute of Eco-Environment and Resources, Lanzhou, China); Jin Huijun; Serban, Mihaela and Luo Dongliang. Shrinking thermokarst lakes and ponds on the northeastern Qinghai-Tibet Plateau over the past three decades: Permafrost and Periglacial Processes, 32(4), p. 601-617, illus. incl. 4 tables, sketch map, 85 ref., December 2021.
Identifying the changes in thermokarst lake dynamics has a significant contribution to landscape-scale hydrology, ecology, and assessment of carbon budgets in permafrost regions. Changes in the number and areal extent of thermokarst lakes and ponds were quantified in a representative permafrost area (150 km2) in the south-central Headwater Area of the Yellow River (HAYR). Water-body inventories were generated from Landsat satellite imageries using the supervised Maximum Likelihood Classification method for three periods: 1986, 2000, and 2015. From 1986 to 2015, the number of water bodies larger than 0.36 ha decreased by 40% (461-277), while the total surface area decreased by 25% (542-406 ha). The ponds category (smaller than 1 ha) recorded the most substantial change, as their number decreased by 44% and their water-surface area by 41%. Many lakes disintegrated, partially drained, and formed several remnant ponds, while the majority of the ponds did not drain completely, but shrank below 0.36 ha. These shrinking patterns are consistent with the warming climate in the HAYR, which suggests intense permafrost degradation. Future research will be focused on a better understanding of water-heat dynamics of thermokarst lakes and ponds in association with permafrost degradation at a landscape scale. Abstract Copyright (2021), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2127
2022002458 Sun Zhizhong (Chinese Academy of Sciences, Northwest Institute of Eco-Environment and Resources, Lanzhou, China); Zhang Shujuan; Li Guoyu; Wu Guilong and Liu Yongzhi. A 10-yr thermal regime of permafrost beneath and adjacent to an alpine thermokarst lake, Beiluhe Basin, Qinghai-Tibet Plateau, China: Permafrost and Periglacial Processes, 32(4), p. 618-626, illus. incl. 1 table, sketch map, 28 ref., December 2021.
Thermokarst lakes are distributed widely in permafrost regions on the Qinghai-Tibet Plateau (QTP), China. Better knowledge of ground thermal variability beneath and around thermokarst lakes is important for understanding future landscape development and hydrological changes. At a typical undisturbed small, shallow, alpine thermokarst lake in the Beiluhe Basin on the QTP, ground temperatures beneath and adjacent to the lake were monitored at four locations with maximum 30 m depth from the lake center to natural ground. The lake is elliptical with an area of »700 m2 and maximum water depth of 0.6 m. Permafrost was present beneath and adjacent to the lake during the monitoring period. However, supra-taliks were present above the permafrost table beneath the lake before monitoring of ground temperature began, but were absent around the lake. The supra-permafrost taliks beneath the lake have thickened over time. The difference in mean permafrost table depth between the lake center and natural ground reached 5.14 m, and permafrost table depths increased beneath the lake, but changed indistinctively around the lake. Mean annual ground temperatures at different depths (5, 10, 20 and 30 m) were higher beneath the lake than around the lake, and mean increasing rates of ground temperature were also greater beneath the lake than around the lake. Ground temperature differences between the lake bottom and natural ground surface are important for understanding ground thermal patterns beneath and around thermokarst lakes. Abstract Copyright (2021), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2107
2022002454 Vasil'chuk, Yurij K. (Lomonosov Moscow State University, Moscow, Russian Federation); Chizhova, Julia N.; Budantseva, Nadine A.; Kurchatova, Anna N.; Rogov, Victor V. and Vasilchuk, Alla C. Stable oxygen and hydrogen isotope compositions of the Messoyakha and Pestsovoe pingos in northwest Siberia as markers of ice core formation: Permafrost and Periglacial Processes, 32(4), p. 558-571, illus. incl. 1 table, sketch map, 41 ref., December 2021.
Pingos are indicators of modern and past conditions of permafrost. In total, 1,620 pingos have been identified on the Yamal and Gydan peninsulas in western Siberia. The main purpose of this study is to consider the distribution of stable isotopes in pingo ice cores formed under conditions of open and closed systems. Two pingos from ice cores of different origin in the continuous permafrost zone of northwest Siberia have been considered: the Messoyaha-1 pingo (10.5 m in height) and the Pestsovoe pingo (17 m in height). Drilling of the ice core was performed with continuous sampling of an undisturbed frozen core. Ice formation was estimated according to the Rayleigh fractionation in a closed-system versus an open-system framework. For the Pestsovoe pingo, a pronounced decrease in d18O values with corresponding increase in dexc with depth indicates a closed system upon freezing of the lake talik from the top down. For the Messoyakha-1 pingo, the values of d18O and d2N showed a weak tendency to decrease with depth, with values of dexc varying randomly. Ice that was segregated in the overlying and underlying sediments had similar values of d18O and d2N and a low slope. Isotopically nonequilibrium ice formation was established for ice which had been segregated in a closed system and for ice cores formed in an open to semiclosed system. The vacuum mechanism of water suction from the surrounding lake or lake talik may have played a significant role during the formation of the upper ice core of the Messoyakha-1 pingo and its additional growth. Abstract Copyright (2021), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2122
2022002460 Yang, Sizhong (GFZ German Research Centre for Geosciences, Section Geomicrobiology, Potsdam, Germany); Liebner, Susanne; Walz, Josefine; Knoblauch, Christian; Bornemann, Till L. V.; Probst, Alexander J.; Wagner, Dirk; Jetten, Mike S. M. and Zandt, Michiel H. Effects of a long-term anoxic warming scenario on microbial community structure and functional potential of permafrost-affected soil: Permafrost and Periglacial Processes, 32(4), p. 641-656, illus., 110 ref., December 2021.
Permafrost (PF)-affected soils are widespread in the Arctic and store about half the global soil organic carbon. This large carbon pool becomes vulnerable to microbial decomposition through PF warming and deepening of the seasonal thaw layer (active layer [AL]). Here we combined greenhouse gas (GHG) production rate measurements with a metagenome-based assessment of the microbial taxonomic and metabolic potential before and after 5 years of incubation under anoxic conditions at a constant temperature of 4°C in the AL, PF transition layer, and intact PF. Warming led to a rapid initial release of CO2 and, to a lesser extent, CH4 in all layers. After the initial pulse, especially in CO2 production, GHG production rates declined and conditions became more methanogenic. Functional gene-based analyses indicated a decrease in carbon- and nitrogen-cycling genes and a community shift to the degradation of less-labile organic matter. This study reveals low but continuous GHG production in long-term warming scenarios, which coincides with a decrease in the relative abundance of major metabolic pathway genes and an increase in carbohydrate-active enzyme classes. Abstract Copyright (2021), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2131
2022002459 Zhang, Yu (Canada Centre for Mapping and Earth Observation, Canada Centre for Remote Sensing, Ottawa, ON, Canada); Touzi, Ridha; Feng, Wanpeng; Hong, Gang; Lantz, Trevor C. and Kokelj, Steven V. Landscape-scale variations in near-surface soil temperature and active-layer thickness; implications for high-resolution permafrost mapping: Permafrost and Periglacial Processes, 32(4), p. 627-640, illus. incl. 3 tables, sketch map, 49 ref., December 2021.
Soil temperature observations in permafrost regions are sparse, which limits our understanding and ability to map permafrost conditions at high spatial resolutions. In this study, we measured near-surface soil temperatures (Tnss) at 107 sites from August 2016 to August 2017 in northern boreal and tundra areas in northwestern Canada. Active-layer thickness (ALT), soil and vegetation conditions were also measured at these sites. Our observations show large variations in Tnss and ALT across an area with a similar climate. This high degree of spatial heterogeneity illustrates the importance of high-resolution mapping of permafrost for infrastructure planning and understanding the impacts of permafrost thaw. Annual mean Tnss varied by 5-6°C among observation sites, which was mainly due to differences in Tnss in winter and spring, indicating the importance of snow conditions on determining landscape-scale variation in near-surface ground temperatures. ALT varied from about 30 cm to more than 120 cm. The variation in ALT among sites did not correlate with thawing season Tnss, but was associated with variation in soil conditions, especially the surface organic layer thickness. Freezing n-factors varied significantly from site to site and among ecotypes, while thawing n-factors were similar among sites, except bare soils. This study shows that ecotypes can be used to map ALT and Tnss at landscape scales in tundra areas, but the method is not as effective in the northern boreal region. Abstract Copyright (2021), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2104
2022002464 Zhou Jiazuo (Chinese Academy of Sciences, Institute of Rock and Soil Mechanics, Wuhan, China); Liang Wenpeng; Meng Xiangchuan and Wei Changfu. Comparison of freezing and hydration characteristics for porous media: Permafrost and Periglacial Processes, 32(4), p. 702-713, illus., 47 ref., December 2021. Includes appendix.
The processes of freezing-thawing and hydration-dissociation change the content of liquid water that coexists with ice or hydrate in porous media, such as frozen soils and hydrate-bearing sediments, changing their physicomechanical properties. In this study, a generalized phase equilibrium equation is presented for both frozen soils and hydrate-bearing sediments by considering the capillary and osmotic pressures. The liquid water content is related to temperature depression, plotted as the soil freezing characteristic curve (SFCC) or the soil hydration characteristic curve (SHCC), by combining the generalized phase equilibrium equation and the soil-water characteristic curve (SWCC). From the SFCC or the SHCC, the phase equilibrium surface can be calculated in the space of temperature, pressure, and liquid water content. The proposed generalized phase equilibrium equation and the model of SFCC and SHCC can help to estimate the physicomechanical properties that depend on the fraction of the liquid or solid phase in porous media. Finally, the SHCC is employed to analyze the dissociation of hydrate-bearing sediments using various methods. Abstract Copyright (2021), John Wiley & Sons, Ltd.
DOI: 10.1002/ppp.2116
2022002449 Connon, Ryan F. (Government of the Northwest Territories, Environment and Natural Resources, Yellowknife, NT, Canada); Chasmer, Laura; Haughton, Emily; Helbig, Manuel; Hopkinson, Chris; Sonnentag, Oliver and Quinton, William L. The implications of permafrost thaw and land cover change on snow water equivalent accumulation, melt and runoff in discontinuous permafrost peatlands: Hydrological Processes, 35(9), Paper no. e14363, illus. incl. 2 tables, sketch maps, 68 ref., September 2021.
In the discontinuous permafrost zone of the Northwest Territories (NWT), Canada, snow covers the ground surface for half the year. Snowmelt constitutes a primary source of moisture supply for the short growing season and strongly influences stream hydrographs. Permafrost thaw has changed the landscape by increasing the proportional coverage of permafrost-free wetlands at the expense of permafrost-cored peat plateau forests. The biophysical characteristics of each feature affect snow water equivalent (SWE) accumulation and melt rates. In headwater streams in the southern Dehcho region of the NWT, snowmelt runoff has significantly increased over the past 50 years, despite no significant change in annual SWE. At the Fort Simpson A climate station, we found that SWE measurements made by Environment and Climate Change Canada using a Nipher precipitation gauge were more accurate than the Adjusted and Homogenized Canadian Climate Dataset which was derived from snow depth measurements. Here, we: (a) provide 13 years of snow survey data to demonstrate differences in end-of-season SWE between wetlands and plateau forests; (b) provide ablation stake and radiation measurements to document differences in snow melt patterns among wetlands, plateau forests, and upland forests; and (c) evaluate the potential impact of permafrost-thaw induced wetland expansion on SWE accumulation, melt, and runoff. We found that plateaus retain significantly (p < 0.01) more SWE than wetlands. However, the differences are too small (123 mm and 111 mm, respectively) to cause any substantial change in basin SWE. During the snowmelt period in 2015, wetlands were the first feature to become snow-free in mid-April, followed by plateau forests (7 days after wetlands) and upland forests (18 days after wetlands). A transition to a higher percentage cover of wetlands may lead to more rapid snowmelt and provide a more hydrologically-connected landscape, a plausible mechanism driving the observed increase in spring freshet runoff. Abstract Copyright (2021), John Wiley & Sons, Ltd.
DOI: 10.1002/hyp.14363
2022002416 Hornum, Mikkel Toft (University Centre in Svalbard, Department of Arctic Geology, Longyearbyen, Svalbard and Jan Mayen Islands); Betlem, Peter and Hodson, Andy. Groundwater flow through continuous permafrost along geological boundary revealed by electrical resistivity tomography: Geophysical Research Letters, 48(14), Paper no. e2021GL092757, illus. incl. sects., 1 table, sketch map, 55 ref., July 2021.
In continuous permafrost regions, pathways for transport of sub-permafrost groundwater to the surface sometimes perforate the frozen ground and result in the formation of a pingo. Explanations offered for the locations of such pathways have so far included hydraulically conductive geological units and faults. On Svalbard, several pingos locate at valley flanks where these controls are apparently lacking. Intrigued by this observation, we elucidated the geological setting around such a pingo with electrical resistivity tomography. The inverted resistivity models showed a considerable contrast between the uphill and valley-sides of the pingo. We conclude that this contrast reflects a geological boundary between low-permeable marine sediments and consolidated strata. Groundwater presumably flows toward the pingo spring through glacially induced fractures in the strata immediately below the marine sediments. Our finding suggests that flanks of uplifted Arctic valleys deserve attention as possible discharge locations for deep groundwater and greenhouse gases to the surface. Abstract Copyright (2021), . The Authors.
DOI: 10.1029/2021GL092757
2022002253 Duvillard, P. A. (Université Savoie Mont-Blanc, Chambery, France); Magnin, F.; Revil, A.; Legay, A.; Ravanel, L.; Abdulsamad, F. and Coperey, A. Temperature distribution in a permafrost-affected rock ridge from conductivity and induced polarization tomography: Geophysical Journal International, 225(2), p. 1207-1221, illus. incl. 2 tables, geol. sketch map, 66 ref., May 2021.
Knowledge of the thermal state of steep alpine rock faces is crucial to assess potential geohazards associated with the degradation of permafrost. Temperature measurements at the rock surface or in boreholes are however expensive, invasive, and provide spatially limited information. Electrical conductivity and induced polarization tomography can detect permafrost. We test here a recently developed petrophysical model based on the use of an exponential freezing curve applied to both electrical conductivity and normalized chargeability to infer the distribution of temperature below the freezing temperature. We then apply this approach to obtain the temperature distribution from electrical conductivity and normalized chargeability field data obtained across a profile extending from the SE to NW faces of the lower Cosmiques ridge (Mont Blanc massif, Western European Alps, 3613 m a.s.l., France). The geophysical data sets were acquired both in 2016 and 2019. The results indicate that only the NW face of the rock ridge is frozen. To evaluate our results, we model the bedrock temperature across this rock ridge using CryoGRID2, a 1D MATLAB diffusive transient thermal model and surface temperature time-series. The modelled temperature profile confirms the presence of permafrost in a way that is consistent with that obtained from the geophysical data. Our study offers a promising low-cost approach to monitor temperature distribution in Alpine rock walls and ridges in response to climate change.
DOI: 10.1093/gji/ggaa597
2022000743 Medford, Aaron K. (University of Maine, School of Earth and Climate Sciences and the Climate Change Institute, Orono, ME); Hall, Brenda L.; Lowell, Thomas V.; Kelly, Meredith A.; Levy, Laura B.; Wilcox, Paul S. and Axford, Yarrow. Holocene glacial history of Renland ice cap, East Greenland, reconstructed from lake sediments: Quaternary Science Reviews, 258, Paper no. 106883, illus. incl. 2 tables, sketch maps, 51 ref., April 15, 2021.
Shrinking glaciers, melting permafrost, and reduced sea ice all indicate rapid contraction of the Arctic cryosphere in response to present-day climate warming, a trajectory that is expected to continue, if not accelerate. The reaction of the Arctic cryosphere to past periods of climate variation can afford insight into its present and future behavior. Here, we examine a ~12,000 year record of glacier fluctuations and meltwater variation associated with the Renland Ice Cap, East Greenland, that extends from the early Holocene thermal optimum through the cooling of the Little Ice Age to present. Sediment records from glacially fed lakes indicate rapid early Holocene deglaciation, with ice extent likely slightly smaller than at present by ~9500 yr BP. Glacial activity resulted in occasional deposition of rock flour in the studied lakes in the early Holocene until at least ~7500 yr BP. Rock flour is absent for much of the period ~7000-4000 yr BP, suggesting ice extent generally was smaller than at present. However, thin layers of blue-gray clay throughout this period may indicate millennial-scale ice expansions, with Renland Ice Cap briefly reaching extents during cold phases that may have been similar to today. Glacial sediment deposition occurred again in the late Holocene at ~3200-3400 yr BP and was followed by a brief glacial episode at ~1340 yr BP and then a major event beginning shortly after ~1050 yr BP. We infer that rock flour deposition in the lakes in the last millennium corresponds with advance of Renland glaciers to their Little Ice Age positions, marked by a fresh, gray drift limit. Radiocarbon dates of in situ plant remains adjacent to the present ice cap indicate a short relatively warm period ~500 yr ago, when ice was within its AD 2011 limit, followed by glacier readvance. The general pattern of ice fluctuations in Renland is similar to that at other ice caps in the region, but also has important differences, including the preservation of a possible mid-Holocene record at times when lower-elevation ice caps in the Scoresby Sund region may have been absent. This finding reinforces the concept that examination of multiple geographic and geomorphologic settings is necessary for a full understanding of ice variations in a region.
DOI: 10.1016/j.quascirev.2021.106883
2022000635 Ji Xiaowen (Nanchang University, School of Resources Environmental & Chemical Engineering, Nanchang, China); Abakumov, Evgeny; Polyakov, Vyacheslav and Xie Xianchuan. Mobilization of geochemical elements to surface water in the active layer of permafrost in the Russian Arctic: Water Resources Research, 57(1), Paper no. e2020WR028269, illus., 76 ref., January 2021. Part of a special issue entitled The Arctic; an AGU joint special collection.
The predicted increase of ground temperatures in the Arctic results in the deepening of the active layer and intensification of geochemical processes. Determining the responses of riparian soil systems to surrounding hydrological flows is important for understanding seasonal changes in hydrological processes. In this study, one soil core from a polygon rim (close to the Taz River, TA) and two soil cores from a riverine terrace (close to the Syoyakha River, SY and Murtyyakha River, MU) in Western Siberia, Russia, and their suprapermafrost water, adjacent surface flows, and river water were sampled for analysis of geochemical elements. Results showed that most elements above their respective detection limits began accumulating in the underlying gleyed layer during September-October in response to the deepest thaw in the active layer. This study focused on the highly mobile elements in the deepest layer; and found that the transport of organic matter in the upper layer carried these elements to both surface water ponds/flows and suprapermafrost water, and further, to the rivers. The efflux of released elements from surface soil to surrounding surface water appeared to be low. The best linear correlation for both surface flows and river water was with Mn; therefore, Mn may be a proxy for predicting the processes occurring within the active layer during the annual summer-autumn thaw. Moreover, landscapes with different ice contents may experience changes in the elements transported to surface waters. A general conceptual model for the response of elements to the thawing-freezing process of the active layer is established. Abstract Copyright (2020), American Geophysical Union. All Rights Reserved.
DOI: 10.1029/2020WR028269
2022002034 Lytkin, Vasylii (Russian Academy of Sciences, Siberian Branch, Institute for Humanities Research and Indigenous Studies of the North, Yakutsk, Russian Federation); Suleymanov, Alexander; Vinokurova, Lilia; Grigorev, Stepan; Golomareva, Victoriya; Fedorov, Svyatoslav; Kuzmina, Aitalina and Syromyatnikov, Igor. Influence of permafrost landscapes degradation on livelihoods of Sakha Republic (Yakutia) rural communities: Land (Basel), 10(2), Article 101, illus. incl. 1 table, sketch maps, 52 ref., 2021. Part of a special issue entitled Permafrost landscape, edited by Fedorov, Alexander N.
Climate change and the degradation of permafrost prove to be severe challenges for humanity. At present, the northern communities and those living in rural areas are already facing the consequences. This article is based on field research conducted in the Yunkyur, Olyokminsky, and Amginsky Districts of Sakha Republic (Yakutia) during 2018-2020. These settlements have one of the richest agricultural traditions in the region; however, the inhabitants of these villages now face serious consequences of permafrost degradation. The authors rely on a mixed set of methods and approaches, including sociological surveys, expert and in-depth interviewing, and appropriate archival and museum materials. Methodology of remote sensing and landscape-geocryological research was integrated. The resulting studies made it possible to demonstrate increasingly widespread thermokarst processes in the key areas studied. The authors determined that the degradation of permafrost has led to problems with the safety and development of the housing stock, especially deformation of houses and outbuildings, and reduction of areas suitable for construction. Territories affected by thermokarst also drop out of agricultural use. Finally, the authors identify some adaptation mechanisms to mitigate the effects of changes in permafrost landscapes.
DOI: 10.3390/land10020101
2022001952 Etzelmuller, Bernd (University of Oslo, Department of Geosciences, Oslo, Norway); Guglielmin, M.; Hauck, C.; Hilbich, C.; Hoelzle, M.; Isaksen, K.; Noetzli, J.; Oliva, M. and Ramos, M. Twenty years of European mountain permafrost dynamics; the PACE legacy: Environmental Research Letters, 15(10), Article 104070, illus. incl. 1 table, sketch map, 57 ref., October 2020.
This paper reviews and analyses the past 20 years of change and variability of European mountain permafrost in response to climate change based on time series of ground temperatures along a south-north transect of deep boreholes from Sierra Nevada in Spain (37°N) to Svalbard (78°N), established between 1998 and 2000 during the EU-funded PACE (Permafrost and Climate in Europe) project. In Sierra Nevada (at the Veleta Peak), no permafrost is encountered. All other boreholes are drilled in permafrost. Results show that permafrost warmed at all sites down to depths of 50 m or more. The warming at a 20 m depth varied between 1.5 °C on Svalbard and 0.4 °C in the Alps. Warming rates tend to be less pronounced in the warm permafrost boreholes, which is partly due to latent heat effects at more ice-rich sites with ground temperatures close to 0 °C. At most sites, the air temperature at 2 m height showed a smaller increase than the near-ground-surface temperature, leading to an increase of surface offsets (SOs). The active layer thickness (ALT) increased at all sites between c. 10% and 200% with respect to the start of the study period, with the largest changes observed in the European Alps. Multi-temporal electrical resistivity tomography (ERT) carried out at six sites showed a decrease in electrical resistivity, independently supporting our conclusion of ground ice degradation and higher unfrozen water content. Copyright (Copyright) 2020 The Author(s). Published by IOP Publishing Ltd.
DOI: 10.1088/1748-9326/abae9d
2022001953 Ji Fang (Harbin Institute of Technology, School of Environment, Harbin, China); Fan Linfeng; Andrews, Charles B.; Yao Yingying and Zheng Chunmiao. Dynamics of seasonally frozen ground in the Yarlung Zangbo River Basin on the Qinghai-Tibet Plateau; historical trend and future projection: Environmental Research Letters, 15(10), Article 104081, illus. incl. 1 table, geol. sketch maps, 34 ref., October 2020.
Seasonally frozen ground (SFG) is a critical component of the Earth's surface that affects energy exchange and the water cycle in cold regions. The estimation of SFG depth has generally required intensive parameterization which has limited estimates in data-scarce regions such as the Qinghai-Tibet Plateau (QTP). We propose a simple yet robust modeling framework employing ground surface temperatures as major model inputs to assess the spatiotemporal patterns of the SFG depth in the Yarlung Zangbo River Basin (YZRB) on the QTP. The model was calibrated using SFG depth measurements throughout the YZRB from 1980 to 2010. Results suggest that the SFG depth in the YZRB has decreased at a rate of 2.50 cm · a-1 from 1980 to 2010. Future projections indicate that the SFG depth in the YZRB will continue to decrease in response to future warming. The present SFG may no longer exist by 2180 under the RCP 8.5 scenario (if not considering the transition of permafrost to SFG). The proposed modeling framework provides an important basis for the evaluation of the hydrological cycles (e.g. surface water-groundwater interactions) in cold regions under changing climatic conditions. Copyright (Copyright) 2020 The Author(s). Published by IOP Publishing Ltd.
DOI: 10.1088/1748-9326/abb731
2022001951 Karjalainen, Olli (University of Oulu, Oulu, Finland); Luoto, Miska; Aalto, Juha; Etzelmuller, Bernd; Grosse, Guido; Jones, Benjamin M.; Lilleoren, Karianne S. and Hjort, Jan. High potential for loss of permafrost landforms in a changing climate: Environmental Research Letters, 15(10), Article 104065, illus. incl. sketch maps, 82 ref., October 2020.
The presence of ground ice in Arctic soils exerts a major effect on permafrost hydrology and ecology, and factors prominently into geomorphic landform development. As most ground ice has accumulated in near-surface permafrost, it is sensitive to variations in atmospheric conditions. Typical and regionally widespread permafrost landforms such as pingos, ice-wedge polygons, and rock glaciers are closely tied to ground ice. However, under ongoing climate change, suitable environmental spaces for preserving landforms associated with ice-rich permafrost may be rapidly disappearing. We deploy a statistical ensemble approach to model, for the first time, the current and potential future environmental conditions of three typical permafrost landforms, pingos, ice-wedge polygons and rock glaciers across the Northern Hemisphere. We show that by midcentury, the landforms are projected to lose more than one-fifth of their suitable environments under a moderate climate scenario (RCP4.5) and on average around one-third under a very high baseline emission scenario (RCP8.5), even when projected new suitable areas for occurrence are considered. By 2061-2080, on average more than 50% of the recent suitable conditions can be lost (RCP8.5). In the case of pingos and ice-wedge polygons, geographical changes are mainly attributed to alterations in thawing-season precipitation and air temperatures. Rock glaciers show air temperature-induced regional changes in suitable conditions strongly constrained by topography and soil properties. The predicted losses could have important implications for Arctic hydrology, geo- and biodiversity, and to the global climate system through changes in biogeochemical cycles governed by the geomorphology of permafrost landscapes. Moreover, our projections provide insights into the circumpolar distribution of various ground ice types and help inventory permafrost landforms in unmapped regions. Copyright (Copyright) 2020 The Author(s). Published by IOP Publishing Ltd.
DOI: 10.1088/1748-9326/abafd5
2022001956 Li, Haiyan (University of Helsinki, Institute for Atmospheric and Earth System Research/Physics, Helsinki, Finland); Valiranta, Minna; Maki, Mari; Kohl, Lukas; Sannel, A. Britta K.; Pumpanen, Jukka; Koskinen, Markku; Back, Jaana and Bianchi, Federico. Overlooked organic vapor emissions from thawing Arctic permafrost: Environmental Research Letters, 15(10), Article 104097, illus., 40 ref., October 2020.
Volatile organic compounds (VOCs) play an essential role in climate change and air pollution by modulating tropospheric oxidation capacity and providing precursors for ozone and aerosol formation. Arctic permafrost buries large quantities of frozen soil carbon, which could be released as VOCs with permafrost thawing or collapsing as a consequence of global warming. However, due to the lack of reported studies in this field and the limited capability of the conventional measurement techniques, it is poorly understood how much VOCs could be emitted from thawing permafrost and the chemical speciation of the released VOCs. Here we apply a Vocus proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF) in laboratory incubations for the first time to examine the release of VOCs from thawing permafrost peatland soils sampled from Finnish Lapland. The warming-induced rapid VOC emissions from the thawing soils were mainly attributed to the direct release of old, trapped gases from the permafrost. The average VOC fluxes from thawing permafrost were four times as high as those from the active layer (the top layer of soil in permafrost terrain). The emissions of less volatile compounds, i.e. sesquiterpenes and diterpenes, increased substantially with rising temperatures. Results in this study demonstrate the potential for substantive VOC releases from thawing permafrost. We anticipate that future global warming could stimulate VOC emissions from the Arctic permafrost, which may significantly influence the Arctic atmospheric chemistry and climate change. Copyright (Copyright) 2020 The Author(s). Published by IOP Publishing Ltd.
DOI: 10.1088/1748-9326/abb62d
2022001238 Kenner, Robert (WSL-Institute for Snow and Avalanche Research SLF, Davos, Switzerland). Mass wasting processes affecting the surface of an alpine talus slope; annual sediment budgets 2009-2018 at Flüelapass, eastern Swiss Alps: Land Degradation & Development, 31(4), p. 451-462, illus. incl. 1 table, 54 ref., February 28, 2020.
An alpine permafrost talus slope at Flüelapass (Eastern Swiss Alps) was observed using annual terrestrial laser scanning measurements between 2009 and 2018. The high-resolution digital elevation models derived from these measurements enabled the detection and quantification of mass wasting processes with an accuracy of a few centimeters. Rock fall, snow avalanche erosion, and debris flow tracks could be distinguished and their quantitative and qualitative contribution to talus slope growth and shaping was examined. Erosion rates were calculated for each of the investigated processes and an estimate for the recession rate of the talus slope head wall is reported. Currently, debris flows supply most of the debris inputs to the talus slope, while snow avalanches were found to play an important role in reshaping its surface morphology. Rock fall causes distinct grain size sorting down the slope, as the travel distance of rocks increase with their size. The presented data and results illustrate the current processes occurring at the talus slope surface, which appear to differ in quantity and quality from those during the onset of the talus slope formation. Abstract Copyright (2020), John Wiley & Sons, Ltd.
DOI: 10.1002/ldr.3462
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The USPA is pleased to announce the availability of an updated searchable database on permafrost-related publications. The American Geosciences Institute (AGI), with support from the National Science Foundation (NSF), has migrated the previous Cold Regions Bibliography to a new platform. Included are the USPA supported PMAs dating back to 2011. The Bibliography is searchable at 
