Distribution of winter frozen soil depth in Qilian Mountain and its response to temperature change

The spatial-temporal distribution of frozen soil depth in response to climate warming during 1960-2004 were analyzed using data collected at 13 meteorological stations on Qilian Mountains. The results show that the spatial distribution of frozen soil depth was obviously influenced by altitude; the maximum average depth was found in Yeniugou station which had the highest elevation. The variation of maximum frozen depth was relatively smoother, while the average frozen depth fluctuated more dramatically across different years. Winter temperature and frozen soil depth changed oppositely. The relationship is shown in the regression equation Y =51.13-8.73X, where Y is the average frozen soil depth, and X is the average temperature. For every 1°C increase in winter temperature, the frozen soil would become 8.37cm shallower. The response of frozen soil depth to temperature was stronger in middle and east parts, but milder in the west part of Qilian Mountains.