尼泊尔冰川1980-2010年的变化特征

The variation of glaciers in Nepal during 1980-2010

利用尼泊尔已发布的冰川编目数据、遥感数据及DEM数字高程模型,利用GIS和Excel对尼泊尔境内冰川的结构特征及1980-2010年的冰川变化特征进行了分析,并运用冰川系统功能模型模拟了同期尼泊尔冰川的变化趋势。结果表明:(1)尼泊尔境内冰川平均规模较小,且冰川分布的海拔差异大。(2)尼泊尔冰川平衡线高度分布受地形影响明显,呈现出反纬向性变化特征,存在若干以高峰为中心的高值区域。(3)1980-2010年尼泊尔冰川整体呈现退缩状态,冰川数量增加了378条,冰川面积和体积均减少,分别减少了24%和29%;小规模冰川或冰川系统退缩更快,1980-1990年冰川变化速率最快。(4)采用历史时期的气温变化率,冰川系统功能模型可以较好地模拟冰川历史时期的变化特征。

Nepalese glaciers locate so remotely that they are very difficult to access and less studied regions in the High Asia. The primary goal of this article is to dissect the characteristics of the variation of the Nepalese glaciers during 1980 -2010. The theory of the study is the glacier system, which regards the glaciers that have some characteristics on an average as a single unit, that can be divided by a river, mountain or region. Triple Nepalese glacier inventories, the Landsat data and the Digital Elevation Model （DEM） were analyzed by using Geographic Information System （GIS） technology and Excel. The data are analyzed from 1980 through 2010. To test the statistical results, the glacier system function model, a dynamic model of glacier change tendency under climate change, which is able to simulate the glacier change macroscopically, was served to simulate the historical glacier change. The result shows that： （1） The mean glacier size in Nepal is small, about 1.02 km2; the glacier equilibrium line altitude （ELA） distributes in a large span, most of which is between 3 250 and 8 650 m. s. 1. , with a mean ELA of 5 601 m a. s. 1. （2） Topography has a determining role to the ELA of Nepalese giaciers. The ELA is rising with latitude with many eminent centers around the mountain peak. （3） During 1980 - 2010, the Nepalese glaciers had retreated as a whole, while the glacier amount had increased with glacier- ized area / reserve decreased, i. e. , 378 glaciers increased and glacierized area and reserve reducing 24% and 29%, respectively, as a whole. Smaller glacier shrank quicker than the larger one. Ratio of glacier retreat was very dissimilar to each other in the altitude belt from 3 150 m a. s. 1. to 8 650 m a. s. 1., with a ratio of -0.01% - -3.33% per year. The Nepalese glaciers reduced faster during 1980 -1990 than that in other two decades. And every sub-glacier system had its own change pace; the smaller sub-glacier system changed quicker than the larger one. （4） Using the historical temperature change rate as the parameters of the glacier system function model, it is possible to imitate the historical glacier system change under global warming.