尼尔基水库上游格点降水数据适用性评估

Suitability evaluation of gridded precipitation dataset for the upstream of Nierji Reservoir

以尼尔基水库上游流域为研究对象,评估了国家气象信息中心空间分辨率为0.5°x 0.5°格点的逐日降水产品数据在该流域的适用性。基于格点降水产品提供的逐日降水f l资料和该流域17个雨量站的相应资料,应用相关系数/?、相对误差/«:和均方根误差3个指标分别对应用格点降雨产品数据的流域面雨M值及旬径流预报值进行精度分析。结果表明:基于格点数据的面雨量值与实测面雨量间相关系数K为0.70,相对误差/为16.64%,均方根误差为4.09 mm,精度满足检验标准,可以用于描述该流域的面雨量值;基于格点面雨量值预报旬径流量时,预报径流值与实测径流值间高度相关;拟合期、检验期径流预报值略微偏大,而外推期存在低估的现象,误差相对较大,但与应用实测面雨量得到的预报径流值误差相差仅3%,该格点降水数据可以替代实测站点的雨量数据用于研究流域。

This study evaluates the suitability of a gridded daily precipitation dataset with 0.5°×0.5°resolution for the upstream basin of Nierji Reservoir.Based on the gridded daily precipitation data and observed data of 17 gauge stations in the studied area,this study analyzed the precision of the gridded data on two aspects:one is the area precipitation value,and the other is 10 days’forecast runoff using three statistical indices,i.e.,correlation coefficient(R),relative bias(RE)and root mean square error(RMSE).The results showed that:when using the gridded data to calculate area precipitation,the R,RE and RMSE values between area precipitation with gridded data and the observed area precipitation are0.7,16.64%,and 4.09 mm,respectively,which meet the inspection standard of the assessment indices,and the area precipitation with gridded data can describe the precipitation for this area overall though there exists overvaluation.When applying the gridded data to forecast 10 days’runoff,the predicted runoff has a high correlation with the observed runoff.The predicted runoff is slightly larger than the observed runoff in training period and testing period while it underestimates the observed runoff in extrapolation period.The error is relatively large,but it is only 3%different from the predicted runoff value by applying the measured area precipitation.In general,the gridded precipitation data can replace the observed precipitation for this study area.