赣江流域TRMM遥感降水对地面站点观测的可替代性

A study of substitutability of TRMM remote sensing precipitation for gauge-based observation in Ganjiang River basin

  • 摘要: 多卫星遥感降水产品为无/缺资料地区的水文过程模拟提供了新的数据来源。结合地面高密度雨量站网,在中国典型暴雨区赣江流域定量评估两种TRMM降水产品(3B42V7和3B42RTV7)的精度,并通过耦合分布式水文模型CREST,探讨了水文模拟中TRMM卫星降水产品对地面观测降水的可替代性。研究表明:3B42和3B42RT与地面观测流域平均月降水相关系数达到0.9以上,偏差在5%以内,日尺度上相关性略差,偏差略有增加。同时设计2种水文模拟对比试验:情景I为静态参数,使用地面雨量站降水率定模型参数,采用卫星降雨验证模型;情景II为动态参数,采用卫星数据重新率定模型参数,再利用卫星降雨验证模型。对比结果表明:情景II中完全使用TRMM降水后模型效果明显改善,证明TRMM卫星数据在赣江流域具有替代地面站点观测的潜力,但需要重新根据卫星降雨率定模型。

     

    Abstract: Multi-satellite remote precipitation sensing products provide a new source of data for hydrological simulation in basins with no or little observation. In this study, TRMM precipitation products (3B42V7 and 3B42RTV7) were evaluated quantitatively, and then coupled with CREST a distributed hydrological model to explore whether TRMM satellite precipitation products can substitute ground observations in the Ganjiang River basin, a typical Chinese storm region. Results indicate that 3B42 and 3B42RT fit well with ground observations, with the monthly correlation coefficients exceeding 0.9 and bias less than 5%, while the indices for daily precipitation is slightly worse. Two scenarios were also designed: Scenario I used static parameters in which gauge precipitation was used to calibrate the CREST model and satellite precipitation was used to validate it; Scenario II used dynamic parameters in which the model was recalibrated based on both satellite precipitation products. Comparison shows that the model performs better after recalibration in Scenario II, proving that mainstream satellite precipitation products have the potential to substitute gauged-based observations after model recalibration.

     

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