Analysis of permafrost effect on water exchange processes

The article focuses on the importance of studying the water exchange role of the permafrost, which currently occupies a quarter of the Earth's land and is 1.5 km deep in some regions, as well as assessing the permafrost impact on the formation of surface and ground water resources and regime. First of all, the permafrost water exchange function is associated with the freezing of water-saturated rocks and thawing of ice-saturated ones. The author gives individual consideration to the water exchange role of the active layer and the effect of the permafrost long-term dynamics on water exchange direction and scale. The water exchange function of the active layer appears due to the seasonal phase transitions of groundwater from a liquid to a solid state and back. Thus, the volume of water formed by the thawing of underground ice accumulated in the active layer in winter has been estimated about 4·1012 m3. In this regard, it is proposed to give cryohydrogenic part associated with the seasonal transitions of groundwater from the liquid to solid state and back in the active layer of the cryolithozone independent consideration within the hydrological (climatic) cycle of the natural water circulation. It is most certain that the permafrost water exchange function is more significant being associated with longterm permafrost development dynamics under the influence of periodic dramatic climate fluctuations. Thus, during the Holocene climatic optimum about 4.5·1015 m3 of underground ice was converted to the liquid phase. The intensity of water formed from the melting of this amount of ice inflowing its surface and underground reservoirs has been estimated about 820 km3 per year. This fact considered, the author proposes to consider the cryolithogenic part separately in the geological cycle of the natural water cycle.

cryolithozone, permafrost, water exchange cycle, groundwater, surface water, natural water cycle