多套降水产品精度评估与可替代性研究

Accuracy evaluation and substitutability analysis of multiple precipitation products for gauge-based observation

以地面雨量站观测降水为准,评估分析了卫星降水数据APHRODITE、TRMM 3B42和再分析降水资料(NCEP)等多套降水产品的精度,并以多套降水数据驱动分布式时变增益模型对云南省元江流域进行水文模拟,进一步探究在流域水文模拟中降水产品对地面实测降雨的可替代性。精度评估结果表明,多套降水产品与实测降水存在着不同程度的差异,TRMM的精度较好,NCEP精度相对较差。流域面降水在月尺度上相关性较好,达0.9以上,日尺度上相关性略差,偏差有所增加;径流模拟结果表明,降水产品驱动模拟的日径流精度降低,但基本能表征日径流变化,具有替代地面雨量观测站点的潜力,且根据降雨产品重新率定后的模型模拟效果会得到改善。

Satellite precipitation products （APHRODITE and TRMM 3B42） and reanalysis data （NCEP） were evaluated quantitatively in this study using rainfall records of gauge-based observation. These datasets were used as forcing data to drive an improved distributed time-variant gain model （DTVGM） to explore whether the precipitation products could be used as a substitute for the rainfall data observed in the Yuanjiang River basin in Yunnan. Results indicate that the accuracy of TRMM is better than the other products. The TRMM datasets of monthly precipitation fit well with the ground observations at catchment scale with correlation coefficients above 0.9 while the correlation of daily precipitation is worse. Streamflow simulations of this study suggest that the simulations of daily streamflow based on the TRMM precipitation products could describe variations in the streamflow, although they have larger deviations than those in the gauge-based observations. Comparison shows that the model performs better after recalibration using precipitation products, suggesting that the precipitation products have a potential to substitute for gauged-based observations.