联合双站InSAR与WoldView DEM估算祁连山西段冰川多时段物质平衡

Multi-period mass balance estimation of glaciers in the western Qilian Mountains based on the combination of bistatic SAR DEM and WordView DEM

冰川物质平衡作为气候变化的敏感指标,对于区域水资源管理,冰川灾害防治以及全球海平面变化预测具有重要意义。随着全球变暖加剧,自2000年来祁连山西段冰川消融加速,然而近年来该地区尤其是老虎沟12号冰川的年际物质平衡变化仍知之甚少。本文利用WorldView光学立体测绘、SRTM和TanDEM-X双站InSAR生成的多源DEM数据,采用DEM差分法分别获得了2013年—2014年、2014年—2015年祁连山西段年际冰厚变化速率和2000年—2015年平均冰厚变化速率,同时获得了相应时段的冰川物质平衡结果。在此基础上以老虎沟12号冰川为例,估算了2013年—2014年、2014年—2015年和2000年—2015等3个时间段的冰川物质平衡变化速率,并分析了降水和气温变化对物质平衡变化的影响。结果表明:2013年—2014年、2014年—2015年祁连山西段冰厚变化速率为-0.35±0.034 m和-0.028±0.004 m,物质平衡变化速率分别为-0.27±0.014 m w.e./a和-0.024±0.084 m w.e./a。2000年—2015年老虎沟12号冰川平均物质平衡为-0.013±0.02 m w.e./a,冰川处于消融状态。冰川亏损速率由2013年—2014年的-0.33±0.04 m w.e./a减缓至2014年—2015年的-0.036±0.09 m w.e./a,这主要与2015年降水增多有关。本文验证了高质量的光学立体测绘卫星DEM数据在求解山地冰川年际物质平衡的可行性。

As a sensitive indicator of climate change,the glacial mass balance is of great relevance to regional water resource management,glacier disaster prevention and control,and global sea-level change prediction.With the intensification of global warming,the melting of glaciers in the western Qilian Mountains has accelerated since 2000.However,in recent years,not much is known about the interannual mass balance changes in this area,especially in Laohugou Number 12 glacier.In this paper,worldview optical stereo mapping,SRTM,and TanDEM-X bistatic InSAR are used to generate multisource DEM data,and the DEM difference method is used to obtain the interannual ice thickness change rate of the western Qilian Mountains from 2013 to 2014 and 2014 to 2015,and the average ice thickness change rate from 2000 to 2015.Results of the glacier mass balance for the corresponding period are obtained.On this basis,taking Laohugou Glacier Number 12 as an example,the glacier mass balance change rate during the three periods of 2013—2014,2014—2015,and 2000—2015 is estimated,and the impact of precipitation and temperature changes on the mass balance changes are analyzed.The results show the ice thickness change rates of the western Qilian Mountains from 2013 to 2014 and 2014 to 2015 were-0.35±0.034 m and-0.028±0.004 m,respectively,and the mass balance change rates were-0.27±0.014 m w.e./year and-0.024±0.084 m w.e./year,respectively.The average mass balance of Laohugou Number 12 Glacier from 2000 to 2015 was-0.013±0.02m w.e./year,and the glacier was in a state of melting.The glacier loss rate slowed down from-0.33±0.04 m w.e./year in 2013—2014 to-0.036±0.09 m w.e./year in 2014—2015,which was mainly related to the increase in precipitation in 2015.This paper verifies the feasibility of high-quality optical stereo mapping satellite DEM data in solving the interannual mass balance problem of mountain glaciers.