湘江流域多源降水与气温产品组合的径流极值模拟精度评价

Accuracy evaluation of runoff extremum simulation for the product combination of multi-source precipitation and temperature in the Xiangjiang River Basin

为探究卫星遥感、再分析产品等多源数据组合径流极值模拟的精度,选取湘江流域TRMM、PERSIANN-CDR、CFSR以及实测数据的8种降水与气温组合,利用水文模型探究不同组合在各径流极值序列中的模拟精度。结果表明:在无实测数据的组合中,TRMM降水与CFSR气温、PERSIANN-CDR降水与CFSR气温2种组合的模拟结果分别最接近径流极高值与径流极低值实测值;除基准组合(实测降水、实测气温),实测降水与CFSR气温、TRMM降水与实测气温分别是径流极高值、径流极低值模拟精度最高的组合;在各径流极值序列中,CFSR降水与CFSR气温、CFSR降水与实测气温2种组合皆严重高估径流极值,最大高估可达651%,表现出模拟误差随径流值减小而增大的特征,其余组合皆低估径流,最大低估可达67.48%,且呈现出误差随径流值减小而减小的特点;降水产品在不同的径流极值序列中表现出的极端降水特征不同,径流极高值序列中TRMM较其他2种降水产品更能反映极端降水的发生频率以及无雨历时等特征,径流极低值序列中PERSIANN-CDR降水对极端降水强度、总量以及连续湿日特征的体现最好。

To evaluate the accuracy of extreme runoff simulation by combining the satellite remote sensing and the reanalysis data,the precipitation and temperature data of TRMM,PERSIANN-CDR,and CFSR,and measured data were selected to obtain eight combination schemes of precipitation and temperature.Hydrological models were utilized to evaluate the accuracy of different combinations in each extreme flow sequence.The results show that:among the combinations of remote sensing data without measured data,TRMM precipitation&CFSR air temperature and PERSIANN-CDR precipitation&CFSR air temperature are the best combinations for simulating the extreme high and low runoff,respectively;in addition to the reference combination(actually measured precipitation&measured temperature),measured precipitation&CFSR temperature and TRMM precipitation&measured temperature are the combinations with the highest simulation accuracy of the high and low runoff simulation,respectively;among the extreme flow series,CFSR precipitation&CFSR air temperature and CFSR precipitation&measured temperature seriously overestimate the extreme flow with the maximum overestimation reaching 651%,and the simulation error increases with the decrease of discharge.The other schemes underestimate the runoff with the maximum underestimation reaching 67.48%,and the error decreases with the decrease of runoff;The characteristics of extreme precipitation vary in different extreme value series.Compared with the other two precipitation products,TRMM can better reflect the frequency of extreme precipitation and the duration of no rain in the high flow series,while the precipitation of PERSIANN-CDR in the low flow series can best reflect the intensity,total amount,and characteristics of consecutive wet days.