摘要
利用1970航测地形图和1991、2000年两期卫星影像数据,人工建立数字高程模型(DEM),解译不同时期的湖泊、冰川边界,在GIS技术支持下采用图谱的方法,定量分析了湖泊、冰川的面积变化情况。结果表明,自1970￣2000年期间,纳木错湖面面积从1941.64km2增加到1979.79km2,增加的速率为1.27km2/a;流域内冰川的面积从167.62km2减少到141.88km2,退缩速率为0.86km2/a。其中,湖面面积在1991￣2000年的增加速率为1.76km2/a,明显大于其在1970￣1991年的1.03km2/a;而冰川面积在1991￣2000年的退缩速率为0.97km2/a,明显大于其在1970￣1991年的0.80km2/a。对比该流域前后两个时期的气温、降水和蒸发变化,发现升温幅度的增加是冰川加速退缩的根本原因,而湖面的加速扩张主要受冰川的加剧退缩及其引起的融水增加影响,但与区域降水量略微增加和蒸发量显著减少也具有密切联系。区域降水增加和蒸发减少及其与湖面扩张之间的内在联系仍是一个需要深入探讨的问题。
Based upon the 1970 aero-photo topographic map and TM/ETM satellite images taken in 1976, 1991 and 2000, the authors artificially interpret boundary of lake water and glaciers and calculate their areas in different stages with the support of GIS. Results show that from 1970 to 2000, lake area increased from 1941.64 km^2 to 1979.79 km^2 with a rote of 1.27 km^2/a, while glacier area decreased from 167.62 km^2 to 141.88 km^2 with a rate of 0.86 km^2/a. The increased rate of lake area in 1991-2000 was 1.76 km^2/a that was faster than 1.03 km^2/a in 1970-1991, while in the same period of time, the shrinking rates of glaciers area were 0.97 km^2/a and 0.80 km^2/a respectively. Climatic factors such as air temperature, precipitation, maximum possible evaporation and their values in warm seasons and cold seasons over the past 30 years are analyzed with linkage of the lake and glaciers variations. The results suggest that temperature increasing is the main reason for accelerated melting of glaciers. Lake area enlargement is mainly induced from the increase of glacier melting water, while slight increase of precipitation and obvious decrease of evaporation are also important factors. Regional precipitation and evaporation and their linkages with lake area enlargement need to be thoroughly studied under the global wanning and glaciers retreating.
出处
《地理学报》
EI
CSCD
北大核心
2007年第3期301-311,共11页
Acta Geographica Sinica
基金
国家重点基础研究发展规划项目(2005CB422002)
国家自然科学基金项目(40331006
40571172)
中国科学院知识创新工程方向性项目(KZCX3-SW-339)~~
关键词
青藏高原
纳木错
湖泊
冰川
遥感
Tibetan Plateau
Namco Basin
lake
glacier
remote sensing
