【摘要】 本研究基于SRTM30数字高程模型数据,在运用D8算法计算流向的基础上,采用两种不同的方案分别提取中国的数字流域。一种是以中国国界为流出边界提取的详细的中国流域图,另外一种是将与中国接壤的周边地区包括在内提取出中国及邻近地区的流域分布图。结果表明,将与中国接壤的周边地区包含在提取范围内,得出的流域分布更能反映真实情况,对于国际间流域分布研究有着很重要的参考意义。而以中国国界提取出来的数字流域,虽然为国内相关研究广泛应用,但这种方法割裂了流域在地理上的天然联系。经过计算,采取第二种方法提取的中国范围内面积大于50 000km2的独立流域一共有23个,占总的流域面积的82.09%,与传统的中国流域划分不同的是,内陆河流域是中国第一大流域,由于处于干旱少雨的地区,该流域为人们所忽视,紧随其后的是长江、黄河、松花江、嫩江等主要流域。面积的估算理论误差在0.25%到1.73%之间。SRTM30数据质量高,1km的分辨率很适合像中国地区这样大范围的流域提取。并且可以采用更高分辨率的数据,继续进行水系的提取及其分级,从而提取出更精细的流域边界和水系分布。更多还原

【Abstract】 Digital watersheds of China are extracted based on SRTM30 in this study.Flow direction is calculated by applying D8 algorithm.There are two schemes in specifying the watershed boundary extraction.One is to extract watersheds in the area including China and its adjacent regions;the other extracts watersheds only within China.The results show that the first scheme is much better in reflecting watersheds crossing the state boundary.Based on the first scheme,main watersheds of China have been clearly identified and the area of each of them has been calculated.Totally,there are 8302 independent watersheds within China,no matter how small they are.Of them,there are 23 watersheds with an area over 50000km2,make up of 82.09% of total land area of China.Different from the traditional perception that Yangtze River watershed is the biggest one in China,Inner land watershed in northwest China is the biggest one,followed by Yangtze River watershed,Yellow River watershed and Songhuajiang River watershed,etc.Meanwhile,the potential calculation error for watersheds with an area more than 5000km2 has been analyzed,which is less than 1.73%.Compared to the traditional division of Chinese watersheds and the result extracted based on GTOPO30,it is verified that SRTM DEM has a higher quality in extracting watersheds of large regions such as China,and the area calculated has a higher credibility.Further work can be done based on more detailed DEM data to extract sub-watershed.更多还原