This study presents data from the first years of permafrost monitoring in boreholes in the French Alps that started at the end of 2009 in the framework of the PermaFrance network. Nine boreholes are instrumented, among which six monitored permafrost temperature and active layer thickness (ALT) over >10 years. Ice-poor and cold permafrost in high-elevation north-facing rock walls has warmed by up to >1(degrees)C at 10 m depth over the reference decade (2011-2020), whereas ice-rich permafrost (rock glacier) temperatures remained stable. ALT has increased at four of the five boreholes for which decadal data are available. Summer 2015 marks a turning point in ALT regime and greatest ALT values were observed in 2022 (available for six boreholes), but thawing intensity did not show an obvious change. At one site with a layer of coarse blocks about 2 m thick, ALT was stable over 2018-2022 and response to the hottest years was dampened. Linear trends suggest an ALT increase of 2 m per decade for some ice-poor rock walls, independently of their thermal state. The data reveal a variety of permafrost patterns and evolution with significant intraregional and local differences. Snow modulates the response to air temperature signal in various ways, with an important effect on near-surface temperature trends and ALT: early snow melting in spring favors an ALT increase in rock walls. Maintaining these monitoring systems and understanding the physical processes controlling heterogeneous responses to climate signals is crucial to better assess permafrost dynamics and to adapt to its consequences.

The high-resolution permafrost distribution maps have a closer relationship with engineering applications in cold regions because they are more relative to the real situation compared with the traditional permafrost zoning mapping. A particle swarm optimization algorithm was used to obtain the index eta with 30 m resolution and to characterize the distribution probability of permafrost at the field scale. The index consists of five environmental variables: slope position, slope, deviation from mean elevation, topographic diversity, and soil bulk density. The downscaling process of the surface frost number from a resolution of 1000 m to 30 m is achieved by using the spatial weight decomposition method and index eta. We established the regression statistical relationship between the surface frost number after downscaling and the temperature at the freezing layer that is below the permafrost active layer base. We simulated permafrost temperature distribution maps with 30 m resolution in the four periods of 2003-2007, 2008-2012, 2013-2017, and 2018-2021, and the permafrost area is, respectively, 28.35 x 10(4) km(2), 35.14 x 10(4) km(2), 28.96 x 10(4) km(2), and 25.21 x 10(4) km(2). The proportion of extremely stable permafrost (< -5.0 degrees C), stable permafrost (-3.0 similar to -5.0 degrees C), sub-stable permafrost (-1.5 similar to -3.0 degrees C), transitional permafrost (-0.5 similar to -1.5 degrees C), and unstable permafrost (0 similar to -0.5 degrees C) is 0.50-1.27%, 6.77-12.45%, 29.08-33.94%, 34.52-39.50%, and 19.87-26.79%, respectively, with sub-stable, transitional, and unstable permafrost mainly distributed. Direct and indirect verification shows that the permafrost temperature distribution maps after downscaling still have high reliability, with 83.2% of the residual controlled within the range of +/- 1 degrees C and the consistency ranges from 83.17% to 96.47%, with the identification of permafrost sections in the highway engineering geological investigation reports of six highway projects. The maps are of fundamental importance for engineering planning and design, ecosystem management, and evaluation of the permafrost change in the future in Northeast China.

Due to the complex topography and localized climate, active layer thickening and permafrost warming varied distinctly in different regions on the Qinghai-Tibet Plateau (QTP). Based on the borehole-temperature data at 93 sites from 2012 to 2018, we analyzed the temporal and spatial characteristics of active layer thickness, permafrost temperature, and relevant climatic factors in 8 typical geomorphological units on the QTP. The active layer thickened at 86 sites and thinned at 7 sites. The permafrost warmed at 89 sites and cooled at 4 sites. The median values of the annual increase rate of active layer thickness were from 0.04 to 0.13 m/a for the monitored regions. The highest rate reached 0.46 m/a, indicating severe permafrost degradation in local areas. The mean annual soil temperatures at a 6-m depth generally increased faster for cold permafrost, and the active layer thickened more significantly in warm permafrost sites. Among these regions, Kekexili Mountains showed a lower increase rate of active layer thickness, and the temperature rise of permafrost in the Fenghuoshan Mountains was more significant. The temporal change of snow cover duration was closely related to the active layer thickness variation in the northern permafrost regions on the QTP (Kunlunshan Mountains and Chumaerhe High Plain). In contrast, the temporal variation of freezing index was the dominant factor in the southern regions (Wuli Basin, Tongtianhe Basin, and Tanggula Mountains). No linear correlation between the temporal variations of climatical factors and active layer thickness variation was found for the regions in the middle of QTP (Kekexili Mountains, Beiluhe Basin, and Fenghuoshan Mountains ). The comprehensive effects of freezing index and snow cover duration result in the different relationships between air temperature variation and permafrost change in different regions on the QTP. These findings are beneficial for understanding the relationship between climate change and permafrost evolution.

The observed global warming has significant impacts on permafrost. Permafrost changes modify landscapes and cause damage to infrastructure. The main purpose of this study was to estimate permafrost temperatures and active-layer thicknesses during the Holocene intervals with significantly warmer-than-present climates-the Atlantic (5500 years BP), Subboreal (3500 years BP) and Subatlantic (1000 years BP) optimums. Estimates were obtained using the ready-to-use models derived by G.M. Feldman, as well as mathematical modeling taking account of the paleogeography of the Holocene warm intervals. The data obtained were analyzed to reveal the regional patterns of warming impacts on different permafrost landscapes. The study results will be useful in predicting future permafrost changes in response to climate warming.

The Cryosphere has been undergoing a worldwide retreat, as seen in the decrease in the areal extent and volume of glaciers and in the areal extent of permafrost. This paper presents a systematic examination of the inherent stability changes of glaciers and permafrost caused by warming. Various study results suggest that over the past 30 years, the internal temperature of glaciers and permafrost exhibits an overall accelerating warming trend. The warming rate peaked in the mid-2000s and slowed slightly for several years afterward. In recent years, however, the warming rate has seemed to pick up again. The warming of glaciers and permafrost has exerted great impact on their stability, displayed as intensified melting, increased glacier surging, enlargement of supraglacial lakes, and increased permafrost degradation. Even without a future temperature increase, some glaciers will continue to shrink, and the number of surging glaciers will increase. The transition from low-temperature to high-temperature permafrost is a noticeable warning sign of a comprehensive degradation of permafrost. These results indicate that warming glaciers and permafrost will exert significant impacts on the hydrology, ecology, and stability of engineering in cold regions. (C) 2019 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.

Between 2002 and 2012, daily soil temperature measurements were made at 10 sites within five alpine ecosystems in the Beiluhe area of the central Qinghai-Tibet Plateau. Changes in freeze-thaw occurrence, active-layer thickness and near-surface permafrost temperature in barren, desert grassland, alpine steppe and alpine meadow ecosystems indicate that alpine ecosystems are sensitive to climate variability. During this time, the average onset of spring thawing at 50-cm depth advanced by at least 16 days in all but the barren alpine settings, and the duration of thaw increased by at least 14 days for all but the desert grassland and barren ecosystems. All sites showed an increase in active-layer thickness (ALT) and near-surface permafrost temperature: the average increase of ALT was similar to 4.26 cm/a and the average increase in permafrost temperatures at 6 m and 10 m depths were, respectively, similar to 0.13 degrees C and similar to 0.14 degrees C. No apparent trend in mean annual air temperature was detected at the Beiluhe weather station. However, an increasing trend in precipitation was measured. This suggests that the primary control on the ALT increase was an increase in summer rainfall and the primary control on increasing permafrost temperature was probably the combined effects of increasing rainfall and the asymmetrical seasonal changes in subsurface soil temperatures. (C) 2014 Elsevier B.V. All rights reserved.

Climate change and engineering activities are the leading causes of permafrost temperature increase, active layer thickening, and ground-ice thaw, which trigger changes in the engineering stability of embankments. Based on the important research advances on permafrost changes and frozen soil engineering in Qinghai-Xizang Plateau, the changes in permafrost temperature and active layer thickness, their relationships with climate factors, the response process of engineering activities on permafrost, dynamic change of engineering stability of Qinghai-Xizang Railway, and the cooling mechanism and process of crushed-rock layers are discussed using the monitoring data of permafrost and embankment deformation. Finally, solutions to the key scientific problems of frozen soil engineering under climate change are proposed.

Two 30-m deep permafrost temperature-monitoring boreholes were installed in bedrock, one at Marble Point and one in the Wright Valley, in the Ross Sea region of Antarctica. A soil climate-monitoring station in till is located near each borehole. The ground surface temperature (GST) was highly correlated with the air temperature at both sites in 2008. Thermal offsets were small (< 1 degrees C) in the till and negligible in the boreholes. The active layer was thicker in the boreholes than in the till, presumably because of the higher thermal diffusivity of the rock. The measured depth of zero annual temperature amplitude was around 27 m at Wright Valley and 25 m at Marble Point. Permafrost thickness was estimated at about 680 m at Wright Valley and 490 m at Marble Point. The GST history, reconstructed using an inversion procedure, suggests a slight cooling from 1998 to 2003 followed by a slight warming to 2008. Longer temperature records or deeper boreholes would be required to establish if long-term climate change has occurred. Copyright (c) 2011 John Wiley & Sons, Ltd.

Results obtained during the International Polar Year (IPY) on the thermal state of permafrost and the active layer in the Antarctic are presented, forming part of ANTPAS ('Antarctic Permafrost and Soils'), which was one of the key projects developed by the International Permafrost Association and the Scientific Committee for Antarctic Research for the IPY. The number of boreholes for permafrost and active-layer monitoring was increased from 21 to 73 during the IPY, while CALM-S sites to monitor the active layer were increased from 18 to 28. Permafrost temperatures during the IPY were slightly below 0 degrees C in the South Shetlands near sea-level, showing that this area is near the climatic boundary of permafrost and has the highest sensitivity to climate change in the region. Permafrost temperatures were much lower in continental Antarctica: from the coast to the interior and with increasing elevation they ranged between -13.3 degrees C and 18.6 degrees C in Northern Victoria Land, from -17.4 degrees C to -22.5 degrees C in the McMurdo Dry Valleys, and down to -23.6 degrees C at high elevation on Mount Fleming (Ross Island). Other monitored regions in continental Antarctica also showed cold permafrost: Queen Maud Land exhibited values down to -17.8 degrees C on nunataks, while in Novolazar-evskaya (Schirmacher Oasis) at 80 m a.s.l. the permafrost temperature was -8.3 degrees C. The coastal stations of Molodeznaya at Enderby Land showed permafrost temperatures of -9.8 degrees C, Larsemann Hills Progress Station in the Vestfold Hills region-recorded -8.5 degrees C, and Russkaya in Marie Byrd Land, 10.4 degrees C. This snapshot obtained during. the IPY shows that the range of ground temperatures in the Antarctic is greater than in the Arctic. Copyright (C) 2010 John Wiley & Sons, Ltd.

[1] We apply traditional geothermal spectrum inversion to precision temperature logs and thermal conductivity from 10 wells in the Canadian Arctic Archipelago (75 degrees to 81 degrees N). Sites lie beyond the Holocene marine limit, and no effect of deep permafrost dynamics is expected. Ground surface temperature (GST) changes correlate with the Little Ice Age and Little Climatic Optimum with average amplitudes relative to 1980 of -2.7 K and +1.6 K, respectively. Results correlate broadly with similar reconstructions for this area and Greenland ice cap holes GRIP and Dye-3 to the southeast. An offshore site in 244 m water yields a Little Ice Age seabed temperature amplitude of -0.7 K, suggesting a moderated climate impact on regional ocean temperatures. Nearshore boreholes where permafrost is aggrading owing to glacioisostatic emergence are excluded; we demonstrate that traditional inversion codes without latent heat of phase change predict the magnitude of the emergence signal but a timing far too recent.