GPM卫星定量降水产品在南流江流域的适用性研究

Applicability of GPM Satellite Quantitative Precipitation Products in Nanliujiang River Basin

在南流江流域定量评估三种GPM IMERG降水产品(FRCal、ER、FRUncal)的精度,并通过新安江模型模拟径流量,探讨IMERG卫星降水产品在南流江流域的水文适用性。结果表明,FRCal、ER、FRUncal与地面观测的平均月降水相关系数(CC)在0.80以上,尤其FRCal更是高达0.94,在日尺度上稍差,但FRCal的CC值亦高达0.71;在不同的时间尺度上,FRCal相对于ER、FRUncal更符合地面降水观测结果;将IMERG产品日降水数据驱动新安江模型模拟的径流与观测流量有一定偏差,与ER(0.46)、FRUncal(0.54)相比,FRCal的纳什指数NSCE(0.59)较大,具有更好的水文模拟性能,但FRCal略微低估了流域汛期的流量。IMERG产品在南流江流域对降水捕捉准确性较高,但在径流模拟方面还需改进。

The accuracy of three kinds of GPM IMERG precipitation products(FRCal,ER and FRUncal)in Nanliujiang River Basin was quantitatively evaluated,and the applicability of IMERG satellite precipitation products in hydrological research of Nanliujiang River Basin was discussed by simulating runoff with Xin’anjiang model.The results are summarized as follows:The average monthly precipitation correlation coefficients(CC)of FRCal,ER and FRUncal with ground observations are all above 0.8,especially FRCal is as high as 0.94,slightly worse on the daily scale,but the CCof FRCal is also as high as 0.71;In different time scales,FRCal is more consistent with the ground observation results than ER and FRUncal;The simulated runoff of the Xin’anjiang model driven by the daily precipitation data of IMERG products has a certain deviation from the observed flow.FRCal has a higher NSCEcoefficient(0.59),which has better hydrological simulation performance compared with ER(0.46)and FRUncal(0.54),but FRCal slightly underestimates the flow of the basin during the flood season.These results show that although IMERG products have good accuracy for rainfall capture in Nanliujiang River Basin,there is still a need to improve runoff simulation.