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  • Characteristics of the seasonal thawing of permafrost in Mongolia
  • Cryopedology ; Freeze-thaw cycle ; Mongolia ; Periglacial features ; Permafrost ; Season ; Soil science ; Summer ; Thawing
  • The paper presents the problem of the permafrost occurrence in Mongolia and discusses the processes of its summer thawing, depending on geographical environmental conditions. These problems are dealt with on the basis of literature and the present
  • Effect of freezing and thawing processes on soil aggregate stability
  • Erodibility ; Freeze-thaw cycle ; Freezing ; Soil ; Soil properties ; Soil temperature ; Turkey
  • This study aims to determine the effects of freezing and thawing processes on the wet aggregate stability of Turkish soils formed from different parent materials, for different aggregate size groups, soil moisture contents at the time of freezing
  • , number of freezing and thawing cycles and freezing temperatures.
  • The allocation of the freeze-thaw weathering mechanism in geocryological studies : a critical comment
  • The widespread claims to freeze-thaw action in cold regions is disputed and a plea for greater care in allocating processes is made. - (AJC)
  • Freeze-thaw simulations on quartz-micaschist and their implications for weathering studies on Signy Island, Antarctica
  • Describes freeze-thaw simulations. Shows anisotropic rocks have asymmetric freeze penetration and that this affects breakdown processes.-(AJC)
  • Summer thaw depths in cold regions and fossil cryoturbation
  • An analysis of data from the literature, on summer thaw depths and cryoturbation in present-day cold areas, shows that the thickness of fossil cryoturbated deposits cannot be correlated to the July temperature of that time. It is suggested
  • Diurnal freeze-thaw depth in rockwalls: field measurements and theoretical considerations
  • Freeze-thaw cycle ; Japan ; Mountain ; Rock ; Temperature ; Weathering
  • but both diurnal and seasonal freezing occur. Diurnal frost and thaw depths were determined from the field data and compared with the theoretical values calculated by the modified Berggren equation. The seasonal frost depth, which could not be directly
  • determined from the field data, was also estimated on the basis of the analysis of the diurnal freeze-thaw depths.
  • A review of the influence of freeze-thaw cycles on soil geotechnical properties
  • Canada ; Cold area ; Freeze-thaw cycle ; Geotechnics ; Periglacial features ; Permafrost ; Quebec ; Soil properties
  • Freeze-thaw cycling affects the geotechnical properties of soils and must be taken into account when selecting soil parameters for stability and deformation analysis of slopes, embankments and cuts in cold regions, especially those underlain
  • by permafrost. This review examines methods of investigation, testing techniques and the impact of freeze-thaw processes on the physical and mechanical properties of soils.
  • A laboratory simulation of rock breakdown due to freeze-thaw in a maritime antarctic environment
  • Results of freeze-thaw simulations on three large blocks of quartz-micaschist are presented. Identification of three types of water to ice phase change from temperature and ultrasonic measurements. It is suggested that the type of phase change
  • results from a particular combination of rock moisture content, solute concentration, freeze amplitude, and rate of fall of temperature. The temperature at which ice thawed inside the rock (-0.7 to 1.9oC) was also found, and this indicates the possibility
  • of freeze-thaw effects without positive temperatures.
  • The classification and assessment of freeze-thaw erosion in Tibet
  • China ; Classification ; Freeze-thaw cycle ; Geographical information system ; Index ; Precipitation ; Soil ; Soil erosion ; Spatial distribution ; Temperature ; Tibet ; Vegetation
  • Based on the analysis of impact factors of free-thaw erosion, this paper chooses 6 indexes, including the annual temperature range, annual precipitation, slope, aspect, vegetation and soil, to build the model for relative classification of freeze
  • -thaw erosion using weighted and additive methods, and realizes the relative classification of the freeze-thaw erosion in Tibet with the support of GIS software. Then a synthetic assessment of freeze-thaw erosion in Tibet has been carried out according
  • Morphometric and spatial analysis of thaw lakes and drained thaw lake basins in the western Arctic Coastal Plain, Alaska
  • Alaska ; Coastal plain ; Cold area ; Geomorphometry ; LANDSAT ; Permafrost ; Proglacial lake ; Remote sensing ; Spatial analysis ; Thawing ; Tundra
  • The aims of this paper are to : identify thaw lakes and drained thaw lake basins (DTLBs) in the western Arctic Coastal Plain (ACP); develop several geometric shape metrics for lakes and basins, and perform statistically-based spatial
  • The occurrence of atmospheric thaw in Poland over the last 50 years
  • Air temperature ; Atmospheric circulation ; Climatic data ; Climatic variability ; Climatology ; Interannual variability ; Poland ; Seasonal variability ; Spatial distribution ; Thawing
  • The study is concerned with the temporal and spatial characterisation of atmospheric thaw variability in Poland. The phenomenon was described on the basis of mean daily values of air temperature for the winter months October-March over the period
  • 1960/61-2009/10 obtained from 34 meteorological stations. It has been shown that atmospheric thaws occur on average as soon as 10 days after the first instance of a decrease in temperature below 0°C lasting at least 3 days. Atmospheric thaws
  • are a constant element of the climate in Poland and occur with a frequency of 30-45% of the calendar winter (December-February) and 30% to almost 50% of the period of the thermic winter. Thaws are most common in the western part of Poland, particularly
  • in the north-west. The spatial distribution of thaw is strongly dependent on longitude and less on height above sea level. Multiyear variability of thaw days is determined by atmospheric circulation. The role of circulation expressed by NAO index
  • in the explanation of the variability of thaw occurrence was statistically insignificant.
  • Variations and trends of the freezing and thawing index along the Qinghai-Xizang Railway for 1966-2004
  • China ; Climate ; Climatic index ; Climatic trend ; Climatic warming ; Freezing ; Qinghai ; Railway ; Thawing ; Tibet
  • Annual freezing and thawing index of 7 meteorological stations along the Qinghai-Xizang Railway were calculated based on daily maximum and minimum temperature records for 1966-2004. Trends of annual freezing and thawing index were analyzed using
  • the Mann-Kendall test and a simple linear regression method. The significant increasing trends can be observed in the annual thawing index for 4 stations except Golmud and Tuotuohe.
  • Evidence for freeze-thaw events and their implications for rock weathering in northern Canada : II. The temperature at which water freezes in rock
  • British Columbia ; Canada ; Freeze-thaw cycle ; Rock ; Temperature ; Threshold ; Weathering
  • Data collected from northern Canada indicate that the temperature at which freezing occurs can vary substantially, even for the same site. The results indicate that any form of freeze-thaw event counting, in the absence of some indicator
  • of the presence of water and that it actually froze, is flawed, as thermal conditions alone are not adequate to indicate the occurrence or not of actual freeze-thaw weathering events. These data suggest that evaluations of freeze-thaw occurrence based simply
  • Scaled physical modelling of mass movement processes on thawing slopes
  • Basse-Normandie ; Experimentation ; France ; Freeze-thaw cycle ; Geotechnics ; Mass movement ; Model ; Slope ; Slope dynamics ; Slope gradient ; Thawing
  • Physical deterioration of sedimentary rocks subjected to experimental freeze-thaw weathering
  • Building materials ; Experimentation ; Freeze-thaw cycle ; Geotechnics ; Lithology ; Sandstone ; Sedimentary ; Sedimentary rock ; Weathering
  • This paper addresses the influence of pre-existing flaws on the durability of ten sedimentary rocks under experimental freeze-thaw weathering. Results suggest that the presence or absence of rock flaws alone does not control deterioration mode
  • Thaw-consolidation effects on the stability of alpine talus slopes in permafrost
  • Alps (The) ; Graubünden ; Mass movement ; Mountain ; Periglacial features ; Slope dynamics ; Soil water ; Switzerland ; Thawing
  • The relative contributions of thaw consolidation and slope-parallel seepage to the generation of overall porewater pressure and resultant potential changes in slope stability are determined in 2 case studies of thawing soils. The first study
  • concerns experimental slopes of frozen silt inclined at 12° and 24° that thawed during scaled centrifuge modelling reported by Harris et al. (2008). The second study concerns a natural slope near Pontresina, eastern Swiss Alps, of coarse-grained talus
  • inclined at 37° and overlying fine-grained soil that contains the permafrost table. In both cases, seepage parallel to the slope was found to contribute much more to the excess porewater pressures in the thawing soils than did thaw consolidation
  • . This suggests that the effects of thaw consolidation on the stability of alpine talus slopes in mountain permafrost may have only minor significance.
  • Thawing permafrost and thicker active layers in sub-arctic Sweden
  • Active layer ; Climatic trend ; Climatic warming ; Forecast ; Periglacial features ; Permafrost ; Subarctic zone ; Sweden ; Temperature ; Thawing
  • warmed and recently rose above 0°C. Increased active-layer thicknesses are correlated with increases in mean summer air temperature, thawing degree-days and, in 5 of the 9 sites, with increases in snow depth.
  • Rockfall activity from an alpine cliff during thawing periods
  • Cirque ; Freezing ; Japan ; Mountain ; Rockfall ; Seasonal variation ; Snow cover ; Temperature ; Thawing ; Weathering
  • onto snow surfaces was measured during seasonal thawing periods. Discussion is focused on the mechanism of rockfall generation and controls of the dimension of rockfall debris.
  • China ; Creep ; Freeze-thaw cycle ; Geotechnics ; Periglacial features ; Permafrost ; Plateau ; Qinghai ; Railway ; Road infrastructure ; Soil properties ; Thawing ; Tibet
  • respectively, the 3 different processes (thaw settlement, creep induced settlement, freeze-thaw induced settlement) are verified and an equivalent permafrost table is proposed.
  • The freeze-thaw weathering regime at a section of the Niagara Escarpment on the Bruce Peninsula, southern Ontario, Canada
  • Fewer freeze-thaw cycles were recorded in the air than at 1 and 3.5 cm in the bedrock, between December 1983 and April 1984. The number of cycles that could be declared geomorphologically effective according to established temperature criteria
  • was normally less than half the total number of freeze - thaw cycles recorded in both air and bedrock. Under the current temperature regime at the field site, few effective cycles are capable of penetrating more than 5 cm into the free face.