Numerical simulation of seasonal snow in Tianshan Mountains

Abstract

Snowfall in the Tianshan Mountains in China is frequent during winter; thus, avalanches have become a severe issue in snow-covered areas. Accumulation and metamorphosis, as well as hydrothermal exchanges with the environment, considerably affect the stability of snow on slopes. Therefore, a hydrothermal model of snow cover and its underlying surfaces must be developed on the basis of meteorological data to predict and help manage avalanches. This study adopted the conceptual model of snow as a porous medium and quantitatively analysed its internal physical processes on the basis of the thermal exchanges amongst its components. The effects of local meteorological factors on snow structure and the redistribution of energy and mass inside the snow cover in the Tianshan Mountains were simulated. Simulation results showed that deformation as a result of overlying snow and sublimation of snow cover at the bottom is the main cause of density variation in the vertical profile of snow cover. Temperature drives water movement in snow. The low-density area of the bottom snow is the result of temperature gradient. The simulation results of the long-term snow internal mass distribution obtained by the method established in this study are highly consistent with the actual observed trend of variation. Such consistency indicates an accurate simulation of the physical characteristics of snow cover in small and microscale metamorphism in the Tianshan Mountains during the stable period.