基于光学立体和InSAR的Grove山地区DEM建立和分析

本文分别利用光学立体和In SAR技术生成了东南极Grove山地区15 m分辨率的ASTER DEM和20 m分辨率的In SAR DEM。在利用ASTER立体像对生成DEM的过程中引入ICESat测高数据作为高程控制以减少错误匹配,提高DEM垂直精度;而在利用ERS tandem数据生成DEM后,选取ICESat测高数据对In SAR DEM进行倾斜面纠正,以消除基线不精确估计等带来的影响。通过与未作控制的ICESat测高数据进行比较,评价了两种DEM的精度并对误差进行了分析。同时,比较了两种DEM的差异,并分析了造成这些差异的原因,探讨了两种技术生成南极冰盖DEM的优势和不足。最后结合两DEM的优势,融合生成了Grove山地区高精度的DEM。

GENERATION AND COMPARISON OF ASTER DEM AND INSAR DEM OF THE GROVE MOUNTAINS AREA

A 15-m ASTER Digital Elevation Model (DEM) of the Grove Mountains area which is located at 72°45′S, 75°00′E was generated by optical stereo technique and an InSAR DEM with resolution of 20 m was derived. ICESat data were introduced in the process of the ASTER DEM construction, and utilized to correct the InSAR DEM. ICESat footprints were used as elevation control points during the ASTER DEM generation to reduce mismatching points. Finally, the vertical accuracy of the DEM was improved. The InSAR DEM was corrected using the quadratic polynomial with ICESat footprints as control points. And this correction has been designed to eliminate errors introduced by inaccurate estimations of the baseline. The accuracies of the ASTER and InSAR DEMs were evaluated using another set of ICESat data and the major error sources were discussed. Furthermore, the two DEMs were compared and analyzed. The specific advantages and disadvantages of these two techniques in DEM construction of the ice sheet in Antarctica were elaborated, and the advantages of both DEMs were combined to generate a high-accuracy DEM of the Grove Mountains area.