Generation of digital elevation model in remote locations using satellite SAR interferometry and the model evaluation

本研究的主要目标是在地面观测困难的偏远地区，利用卫星SAR干涉测量技术生成数字高程模型（DEM），并使用独立的方法对其进行评估。利用卫星SAR三通方法生成了日本越冬站所在的Lutzow-Holm湾周围冰盖的DEM。与最先进的全球DEM相比，使用包括GPS结果在内的地面观测作为参考，其精度提高了一个数量级。另一方面，明确了生成过程中存在的几个问题。为了精确地推导出地面冰架与浮冰架之间的接地线，对Lutzow-Holm湾以西的Baudouin冰架进行了SAR干涉测量。利用条纹的空间差异清晰地识别和跟踪接地线。垂直位移的计算结果与具有逆气压计效应的海潮模型的计算结果一致。为了建立和评估快速移动目标的地面观测方法，在快速海冰点和地面岩石点之间进行了GPS观测。同时观测证实，GPS能够以1 ~ 2厘米的精度探测海冰的垂直位移。如上所述，本研究确定了SAR干涉测量在偏远地区生成DEM的有效性。与有效的GPS地面观测相结合，将能够对整个冰雪覆盖地区进行更精确的监测。

The primary goal of this study is to generate a digital elevation model (DEM) using satellite SAR interferometry for remote regions where ground observations are difficult, and is to evaluate them with independent methods.A DEM of the ice sheets around Lutzow-Holm Bay, where the Japanese wintering station is located, was generated with the satellite SAR three-pass method. Comparisons with the state-of-the-art global DEM showed improvement in its accuracy up to an order, using ground observations including GPS results as references. On the other hand, a few problems in the generation process were clearly identified.To derive a groundling line precisely, which forms the boundary between grounded ice sheet and floating ice shelf, the SAR interferometry was applied to Baudouin Ice Shelf to the west of Lutzow-Holm Bay. The grounding line was clearly identified and tracked from the spatial difference in fringes. The derived vertical displacement was consistent with the one which was inferred from a ocean tide model with inverse barometer effect.To establish and evaluate the methods of ground observations for the rapidly moving objects, GPS observations were conducted between the points on fast sea ice and on ground rocks. Simultaneous observations confirmed that the GPS can detect the vertical displacement of sea ice in an accuracy of 1-2 cm.As above, this study established the availability of the SAR interferometry to DEM generation for remote locations. Combined application with the effective GPS ground observations will enable much precise monitoring of the whole ice-covered area.