青藏高原河流地貌定量研究的基础--SRTM3空白数据填充方法剖析及数据

河流地貌和侵蚀是构造地貌研究的核心内容。90m分辨率的SRTM3数字高程模型被广泛运用于构造地貌学的研究,但数据空白区是其在河流地貌定量研究中的瓶颈。对SRTM3数据与中国1∶25万DEM数据的对比分析表明,1∶25万DEM数据在生成数字河网和河流纵剖面方面不如SRTM3数据,尤其是其在平原区数字河网提取中易发生错误,但在高山峡谷地区数据质量较好,而这正是SRTM3数据空洞的主要区域。对比国内外各种SRTM空洞填补方法发现,相对于算法的改进,高精度数据的参与是填充SRTM3数据空洞的关键。因此,利用SRTM3与1∶25万DEM数据的互补性,对SRTM3进行数据优化,是现阶段青藏高原河流地貌定量研究的基础。详细介绍了SRTM3空洞充填的步骤,具有实际参考价值。

The basis of quantitative analysis in fluvial geomorphology of Qinghai-Tibet Plateau--the processes and performance of SRTM3 void-fil

Fluvial erosion is among the core components in tectonic geomorphology. The 90m-resolution SRTM3 DEM has been widely used in tectonic geomorphology, but the void data is the bottle-neck that hampers its application in quantitative fluvial geomorphology. In this paper, we compare the satellite-derived SRTM3 with the 1：250000 scale topographical map-derived DEM of 90m pixel resolution （so called 1：250000 DEM）. 1：250000 DEM results in artifacts and distortions are larger than the SRTM3 in generating river networks, particularly in relatively flat regions of flood plains or sedimentary basins. However, it is better than the SRTM3 in the steep and mountainous terrain, regions where SRTM3 has most of its data voids. Comparison of various studies on SRTM3 hole-filling suggests that high-resolution DEM patching is the key, and the choice of algorithm is of the secondary importance in improving SRTM3 data quality. Using the complementary 1：250000 DEM to fill the holes in SRTM3 is effective in quantitative studies on fluvial geomorphology, especially in dissected margins of the Tibetan Plateau. We also describe the procedure of SRTM3 data void-filling, for educational and practical purpose.