近20 a来玛纳斯河流域南山冰雪动态变化特征分析

利用1990-2010年的TM影像和DEM数据,通过面向对象的分类方法提取了玛纳斯河流域南山4个时期的冰雪分布信息,并结合近20 a（1987-2007年）的气温资料对研究区冰雪时空分布特征和变化原因进行了研究。结果表明：（1）1990-2010年间,研究区冰雪面积从1442.32 km²退缩到710.54 km²,面积减少了50.7%。（2）1990-2010年间,冰雪变化主要呈现退缩的态势,尤其在海拔4000 m以下,面积减少更为剧烈,在海拔4000 m以上相对平缓。这种现象在研究区东区表现的更为明显,西区相对较小。（3）自1987年以来,气温的升高是冰雪面积不断退缩的主要原因之一。

The Study of Glacier Dynamic Change in South Mountain of Manas River Watershed in the Past 20 Years

Glaciers play an important role in the global climate system. Regular methods of analyzing glacier changes are not applicable in some areas of the region. The use of remote sensing (RS) techniques and GIS provides an efficient tool to analyze the status and the changes of glaciers. The study utilized Landsat TM and DEM data from 1990 to 2010, and analyzed the glaciers’ temporal and spatial distribution characteristics and changes in the South Mountain of Manas River Watershed by the method of object-oriented classification. And we discussed the reasons for these changes by making use of the temperature data of nearly 20 years (1987-2007). The results show that: (1) between 1990 and 2010, glaciers in the study area had retreated from 1442.32km² to 710.54km², and the overall area had decreased by 50.7%. (2) From 1990 to 2010, the main trend of the glacier change is retreating. Especially below the altitude of 4000m, the glacier area had decreased sharply, while above the altitude of 4000m, the change was relatively moderate. This phenomenon was much more obvious in the eastern area and relatively gentler in the western study area. (3) Since 1987, the increasing temperature was one of the main reasons for the continuous glacier retreatment.