DEM辅助偏移量跟踪技术的山地冰川运动监测研究

Research on the DEM-assisted offset tracking technique applied to glaciers movement monitoring

为改善传统偏移量跟踪技术获取山地冰川表面位移时受大空间基线和地形起伏影响较大的状况,研究了数字高程模型(digital elevation model,DEM)辅助的偏移量跟踪技术。以西藏自治区康马县和浪卡子县之间的卓莫拉日山系东段冰川区为例,选取2对不同空间基线长度的TerraSAR-X数据应用传统的和DEM辅助的偏移量跟踪技术进行处理,并对比非冰川区的2种偏移量提取结果;针对2景入射角和成像范围有所差别的COSMO-SkyMed影像开展了DEM辅助的偏移量跟踪数据处理。结果表明,DEM辅助的偏移量跟踪技术不仅降低了空间基线和地形起伏引起的误差,而且还能应用于同一传感器不同波束模式的合成孔径雷达(synthetic aperture Radar,SAR)影像,扩大了SAR数据的使用范围。

To improve the offset results influenced by large spatial baseline and topography when traditional offset tracking technique is applied to extracting mountain glaciers surface movement,the authors studied a DEM-assisted offset tracking technique.Two pairs of TerraSAR-X images with different baseline lengths which cover the eastern section of Chomo Lhari Mountains located in Kangmar and Nagarze County of Tibet were selected to test the traditional and external DEM-assisted offset tracking techniques in this paper.And the offset results of the two methods in ice-free region were comparatively studied.A pair of COSMO-SkyMed images acquired by different beam modes,with different incidences and covers,were selected and processed with DEM-assisted offset tracking technique.It is shown that the DEM-assisted offset tracking technique could obtain more reliable offset results than the traditional technique where the terrain is steep and the spatial baseline is large.The technique can also apply to SAR images which have different beam modes and can make more SAR data useful for glaciers surface movement monitoring.