高分一号山地冰川运动速度提取与分析

Extraction and analysis of mountain glacier movement from GF-1 satellite data

近年来国产遥感卫星数据增多,但在山地冰川运动速度监测研究中,国产卫星遥感数据的使用却很少。基于此现状,本研究利用"高分一号"卫星数据(GF-1)对藏东南雅弄冰川运动速度进行了提取。通过与同分辨率、同时段的Landsat 8数据进行对比,以及利用非冰川稳定区域的残余位移和冰川主冰流线剖面运动速度两方面,评估了GF-1数据提取的冰川运动速度的精度。结果表明:GF-1数据在非冰川稳定区域的平均偏移量为7.48 m·a^(-1),虽较Landsat 8数据的高(平均偏移量4.58 m·a^(-1)),但小于冰川平均运动速度的5%;GF-1数据与Landsat 8数据在2015年—2016年时段内的冰川主冰流线运动速度变化趋势一致,两者的偏差均方根为7.41 m,小于冰川平均运动速度的5%。研究结果证明了国产高分一号卫星遥感数据在青藏高原山地冰川运动速度监测应用中的可行性。

With ongoing and accelerating global climate change,temperate glaciers are very sensitive to variations in the temperature and precipitation,and thus are in fact regarded as natural indicators of climate change.Glacier velocity,which is a combination of ice deformation,bed deformation,and glacier sliding,is an important parameter to better study the dynamics of glaciers and their interplay with climate changes in the region.In situ observations serve as one of the most accurate methods for measuring glacier velocity,but the remote areas where glaciers develop have prevented frequent visitation by people.Remote sensing is more effective in glacier monitoring and has been applied to study glacier velocity in many regions of the Tibetan Plateau,such as in Karakoram,Himalaya,West Kunlun,and other areas.In recent years,the Chinese high-resolution optical remote sensing images has gradually increased,but there was not much use of Chinese produced satellite remote sensing images for monitoring glacier flow parameters in mountain regions.In view of this situation,this study tried to apply the domestic"GaoFen-1"satellite images(GF-1)to the extraction of Yanong Glacier flow in southeast Tibet.By preprocessing and applying feature tracking on all available pairs within a defined period to derive the velocity,the reliable glacier velocities can be obtained by selecting stable ground control points from the ice-free areas to register these GF-1 data and the offset can be computed.The accuracy of the glacier flow velocity derived from GF-1 data was assessed by the residual displacements in non-glacial stable regions and glacier flow velocity along the longitudinal profile of the Yanong Glacier compared to that of Landsat-8 data in the same resolution and at the same Periods.The evaluation results showed that:The average deviation of GF-1 data in non-glacial stable regions was 7.48 m·a^(-1),which was higher than that of landsat 8(the average deviation was 4.58 m·a^(-1)),but less than 5%of the average velocity of glacier;The GF-1 data was consistent with Landsat 8 data in the change trend of glacier flow velocity along the longitudinal profile in the period from 2015 to 2016,and the mean square root of the deviation between them was 7.41 m,which was also less than 5%of the average glacier flow velocity.The results proved the feasibility of the application and the unique advantages of GF-1 satellite remote sensing data in monitoring of the mountain glacier velocity on the Qinghai-Tibet Plateau.