Abstract: The meteorological data (1959-2003) from 17 weather stations in the area of Tianshan Mountainous are analyzed to explore the trend characteristics in temperature and snow cover. The abrupt change test of the snow cover depth is carried out by using Mann-Kendall method, and the spatial distribution of maximum snow cover depth is also given by employing the GIDS interpolation and the DEM data. The results show that winter mean temperature had a rising trend at a rate of 0.44℃/10 a, which is closely related to the mean temperature of the Northern Hemisphere ( r = 0.54). Winter minimum temperature increased at a rate of 0.79℃/10 a, greater than that for winter mean temperature. Maximum snow cover depth in winter has obviously increased at a rate of 1.15 cm/10 a, and in comparison with long-term normal, it has on the average increased by about 16% during the period of 1991 to 2003. The result of the abrupt change test of snow cover depth indicates that the abrupt change occurred in 1977. There were two places, Zhaoshu and Nileke, located in the Western Tianshan Mountains, with the greatest snow cover depth augment of 39.3% and 39.7%, respectively. There was a primary periodicity of about 2.8 years for snow cover. In addition, snow days with the snow cover depth more than 10 cm increased distinctly. There was no obvious change in the beginning and ending dates of snow cover.

Key words: snow cover, Tianshan Mountains, climate change