基于WRF-Hydro模式的沂河流域水文气象模拟参数优化研究

Optimization of hydro-meteorological simulation parameters in Yihe River Basin based on WRF-Hydro model

为优化适用于沂河流域WRF-Hydro模式水文气象预报模拟的参数方案,利用中国区域地面气象要素驱动数据与沂河流域内气象站点实测降雨数据驱动WRF-Hydro模式,采用分布率定法对模式几项主要的水文参数进行参数率定分析,选取相似暴雨引发的洪水过程对率定结果进行参数拟合验证。结果表明:WRF-Hydro模式的入渗系数和地表粗糙度对产流量影响具有非线性特征;河道曼宁糙率同时对产流量和汇流速度均有较明显的影响,曼宁糙率系数越小,汇流速度越快,产流量越大,峰现时间越早。入渗系数和河道曼宁糙率在所有率定参数中最敏感,尤其在非饱和土壤条件下。当入渗系数和河道曼宁糙率乘子分别为1.5和0.7、地表持水深度和地表粗糙度取模式默认值1.0时,径流过程模拟效果最优。

In order to optimize the parameter scheme suitable for WRF-Hydro hydro-meteorological forecast and simulation in the Yihe River Basin,the distribution calibration method was adopted to analyze several main hydrological parameters of WRF-Hydro model,which was driven by the China meteorological forcing dataset(CMFD)and precipitation data observed by the meteorological stations in the Yihe River basin.The flooding process caused by similar rainstorms was selected to carry out parameter fitting verification of the calibration results.The results show that the infiltration coefficient and surface roughness of the WRF-Hydro model have nonlinear characteristics on the yield flow.MannN roughness of the river has an obvious influence on both production flow and confluence velocity.The smaller the MannN roughness coefficient is,the faster the confluence speed is,the larger the production flow is and the earlier the peak occurrence time is.The infiltration coefficient and manning roughness are the most sensitive among all the measured parameters,especially in unsaturated soil.When the infiltration coefficient and MannN roughness multiplier are 1.5 and 0.7 respectively,and the default value of surface water holding depth and surface roughness is 1.0,the simulation effect of the runoff process is optimal.