The Models of Permafrost for Arid and Alpine Regions

Abstract

Abstract Stationary models of the thermal regime of permafrost taking into account water evaporation and ice sublimation within upper layer of soil are submitted. The results of Chinese researchers in mountainous Tibet and theoretical approach of Russian scientists for Northern Tien Shan are discussed. The thickness of the frozen rocks may reach an unexpectedly very large depth up to 100 m and more. Traditional stationary model of permafrost (Model Problem #0) was examined. The authors of the paper theoretically based the thermal regime of formation permafrost of cryolithozone in the highlands (two-stratum Model Problem #1). The new mechanism of formation of the thermal regime caused evaporation and sublimation processes in dispersed rocks in conditions of arid (high land) climate are suggested. Evaporation when filtering moisture in the upper soil layers is like heat sink. Then this process becomes the primary for the temperature field variations inside coarse clastic sediments. Additionally ice sublimation can increase heat dissipation in dispersed rocks. Three-stratum Model Problem #2 with a certain subsurface volumetric layer under frost desiccation was introduced. This soil layer being between the upper one of evaporation and the deep one of permafrost may generate a significant heat effect on the depth of freezing. Temperature minimum of the thermal system is formed in subsurface layer and cause heat sink into frozen soil depth. Numerical evolutions for the proposed models correspond to experimental data on the intensity of evaporation and sublimation for the surface and subsurface layers of permafrost, as well as the processes of cooling and freezing in dispersed rocks. This research will be in demand in engineering Cryolithology and Glaciology.