基于地形地貌资料的Nash单位线参数规律研究

为了将Nash单位线应用在无资料地区,基于DEM研究Nash单位线的参数规律.以皖南山区若干中小流域为试验流域,率定Nash单位线参数;利用Arc GIS 10.1提取的地形地貌因子和地表覆盖类型对Nash单位线参数进行回归分析和通径分析,建立基于DEM的Nash单位线参数推求公式,并进行检验.回归分析结果表明该推求公式回归效果显著,具有统计学意义;通径分析结果表明面积坡度是最根本的解释变量,对Nash单位线参数起决定作用.基于DEM的Nash单位线参数推求公式不依赖于实测资料,可在无资料山区流域推广应用.

Study on the parameter regularity of Nash Unit Hydrograph based on DEM and geomorphic data

In order to apply Nash Unit Hydrograph to ungauged basins, we studied the parameter regularity of Nash Unit Hydrograph based on the DEM data. The 29 medium and small basins in Wannan mountainous watershed are used as experimental basins to calibrate the parameters of Nash Unit Hydrograph. Geomorphic parameters and surface land cover types obtained by ArcGIS 10.1 are adopted to make multiple regression analysis and path analysis of the parameters, and establish the formula which calculates the parameters of Nash Unit Hydrograph based on the DEM. The result of regression analysis shows that the formula has high statistical significance. The result of path analysis shows that slope is the fundamental explanatory variable, which plays a decisive role in calculating the parameters of Nash Unit Hydrograph. The formula independent on measured data can be generalized and applied to ungauged basins.