关键词: 阿拉套地区, 冰川退缩, 气候变化, GIS, RS

Abstract: Mountain glaciers are important fresh water resources in the arid region and they are also one of potential climate indicators because of their sensibility to climate changes. It is estimated that 82.2% of glaciers in western China have been in a state of retreat，which the glacial area decreased by 4.5% in recent 50 years. Under this background，we can not only understand the characteristics and trends of glacier change，but also understand the relationship of glacier response to climate change，and thus likely to predict future changes in glacier. Researches on glacier change have been limited in Chinese Tianshan Mountains，despite the fact that the number of glaciers in the Tianshan Mountains is the largest among all mountain ranges in China，and the glaciers in this region provide very important water resources for local economic development and drinking water for man use. The Alatau Mountains belong to Tianshan Mountain System. Most of the researches on glaciers were sited in Tianshan Mountains but not in Alatau Mountains. Therefore，the glaciers of Alatau Mountains were selected as the study area in this paper. TM and ETM+ Landsat data from 1990 to 2011 were used to map the glacier extents by applying remote sensing image processing and visual interpretation. The details of glaciers change during the last 22 years in the Alatau regions were obtained by using GIS. Meanwhile，the meteorological data were analyzed in the paper. The results showed that the Alatau area glaciers experienced a general shrinkage，the total glacier area in the study area decreased by 20.24% from 1990-2011. Massive glaciers decomposition caused small-scale glaciers increase in total areas and numbers. The paper analyzed the reason of large change rate of glaciers，and the results indicated that the large change rate of glaciers is caused by the big proportion of small glaciers，which glaciers smaller than 1 km² for nearly 90% in total glaciers. At the same time，the distribution characteristics of spatial structure for the glaciers were analyzed. Based on the fractal theory，it shows that the melting rate of glaciers in the study area will remain high because of the climate warming，which is mainly caused by the area and length changes of these glaciers. By analyzing the climate records （annual mean temperature，summer mean temperature and annual precipitation） and glacier variation in the research area，it was stated that glacier changes were a response to summer temperature increase. Annual precipitation also showed an upward trend，but it had not compensated the mass loss due to ablation. Besides，topographic condition and the scale of glacier were key factors for glacier changes as well. Compared with other western regions，the Alatau region glaciers retreat exhibited rapid trend.

Key words: Alatau region, glacier shrinkage, climate change, GIS, RS