应用30 m ASTER GDEM数据估算贵州县域地表河网密度的适应性

Adaptability of 30 meters ASTER GDEM data for estimating county-level surface drainage network density of Guizhou province

数字高程模型(DEM)是快速获取河网密度的常用数据源。分析DEM用于估算特定区域河网密度的适应性,是拓展DEM应用范围的重要基础工作。应用Arc GIS的水文分析工具,以空间分辨率为30 m的ASTER GDEM为数据源,估算贵州省各县域单元不同集水面积阈值下的河网密度。结果发现:运用30 m ASTER GDEM数据估算贵州县域地表河网密度时,若全省范围只使用同一个集水面积阈值,估算出的县域地表河网密度与实测值偏差较大,纳西效率系数(NSE)为负值,表明适应性较差。在未来研究中,有必要根据贵州地貌分区、岩层分组和水文气象条件对集水面积阈值分别设定,从而提高30 m ASTER GDEM估算贵州县域地表河网密度的适应性。

Digital elevation model （DEM） is commonly applied to rapidly access drainage network density. For expanding the scope of DEM applications, it is import to analyze the adaptability of DEM for estimating surface drainage network density in certain areas. Basing on the hydrological analysis tool in ArcGIS environment, ASTER GDEM data with spatial resolution of 30 meters is used to estimate county-level surface drainage network density of Guizhou province under different catchment area thresholds. The results show that： when using the 30-meter ASTER GDEM data to extract the county- level surface drainage network density of Guizhou, if the same catchment area threshold is used in the whole province, there are large deviation between the measured and the estimated county-level surface drainage network density, the value of Nash-Sutcliffe efficiency coefficient （NSE） is negative. And this result indicates that the adaptability of 30-meter ASTER GDEM data for extracting county-level surface drainage network density is poor. In the future research, it is necessary to set the threshold of catchment area according to the geomorphologic division, rock stratigraphy and hydrological and mete-orological conditions of Guizhou, so as to improve the adaptability of 30-meter ASTER GDEM in the re- search of the county-level surface drainage network density of Guizhou.