基于曲线割线斜率法的水文特征提取

Extration of Hydrological Characteristics Based on Slop of Curve-Secant Method

以晋江流域为研究对象,基于GIS环境下30 m空间分辨率的DEM数据,对流域水文特征进行了分析。针对汇流格网阈值设置存在的主观性,提出用曲线割线斜率法克服传统目视判读的主观性,用该方法计算出的集水面积阈值为14.265 km^2,依此阈值提取晋江流域水系并将晋江流域划分为7个子流域。结果表明:晋江流域河网密度为0.192km/km^2,河长比为2.4,分叉比为3.3,水系分形维数为1.36,流域地貌发育处于幼年时期;各子流域的河网密度为0.183~0.207 km/km^2,其中湖洋溪流域的河网密度最大,为0.207 km/km2,坑仔口溪流域的最小,为0.183 km/km^2。

Hydrological characteristics of Jinjiang River basin were analyzed based on DEM with 30 m resolution. For the subjectivity of catchment threshold setting, the slope of curve?secant method was put forward to select the best catchment threshold value. This method overcame the subjectivity of traditional visual interpretation, calculating process simple and intuitive and the results depending on the continuous changing curve had higher precision. By this method, the calculated catchment threshold value was 14. 265 km2 . Extracting Jinjiang River basin with the threshold, we could divide Jinjiang River basin into 7 sub?catchments. The results show that the drainage density of Jinjiang River basin is 0.192 km/km2, stream length ratio is 2.4, bifurcation ratio is 3.3 and fractal dimension is 1.36, Jinjiang basin landform development now is in infancy. The drainage density of each sub?catchment ranges from 0.183 to 0.207 km/km2 and the drainage density value of Huyang River basin is the maximum and Kengzaikou River basin is the minimum.