1974～2012年珠穆朗玛峰地区冰川物质平衡遥感监测研究

Mass Change of Glaciers in Mt.Qomolangma(Everest) Region from 1974 to 2012 as derived from Remote Sensing Data

基于资源三号卫星立体像对、SRTM及地形图等数据,对珠峰地区南北坡14条大冰川1974~2012年的物质平衡进行评估,分析了物质平衡变化的特点。结果表明:(1)1974~2012年研究区整体冰川物质平衡为-0.31±0.03m w·e·a^(-1),其变化趋势总体上呈加速的趋势(1974~1999年为-0.27±0.03 m w·e·a^(-1),1999~2012年为-0.35±0.06 m w·e·a^(-1))。南坡物质损失(-0.38±0.03w·e·a^(-1))大于北坡(-0.27±0.03w·e·a^(-1)),各冰川间物质平衡差异大。(2)气温升高是珠峰地区物质亏损的主要原因,局地地形与气候影响冰川物质平衡的空间差异。北坡海拔5 500~6 000m之间,表碛区域冰川消融相对于裸冰区域更加强烈,且随海拔变化存在先上升后下降的趋势。局地气候差异和表碛厚度分布的不均匀致使物质损失的海拔相关性差。(3)冰川物质强烈消融,导致部分冰川表面和末端形成冰湖,冰湖的形成与扩张同时加速了冰川消融。

In this study,glacier mass changes are investigated for the period 1974^2012 for 14 glaciers larger than 3 km2 on south and north slopes in Mt.Qomolangma（Everest）region based on ZY-3 images,SRTM DEMs and topographic maps.In general,a continuous mass loss（-0.31±0.03 m w·e·a^（-1））for glaciers on south and north slopes of Mt.Qomolangma could be observed between 1974 and 2012.The mass budget of 14 glaciers was-0.27±0.03 w·e·a^（-1） for the period 1974^1999 and-0.35±0.06 w·e·a^（-1） during 1999^2012.Glaciers on the south slope lost mass at a rate of-0.38±0.03 w·e·a^（-1）,was larger than glaciers on the north slope which was at a rate of 0.27±0.03 w·e·a^（-1）.And these glaciers change are heterogeneous and differ spatially.The main reason for negative mass budget may be attributed to the increasing air temperature,heterogeneous glacier mass balances were responded to different climate conditions.Debris-covered regions obviously exhibited higher thinning rates on the north slope about 5 500^6 000 m.However,the dependence of mass change on altitude is not significant in other regions.The main reason for this may be attributed to the heterogeneous debris thickness except for different climate conditions.Glacial lake expansion is the result of glacier rapid ablation,and also accelerates glacier melting.