中国大陆流域分区TRMM降水质量评价

Evaluation of TRMM 3B42V7 at the basin scale over mainland China

  • 摘要: 根据中国境内2 257个气象站点1998-2013年逐日降水资料,结合流域分区,采用探测准确性、相关系数以及相对误差等指标,对热带降水测量(TRMM)降水精度和一致性进行系统评价。结果表明:① TRMM日降水准确性从东南沿海向西北内陆递减;② 气象站点年均降水日数显著大于TRMM年均降水日数;③ 西北片区以外气象站点降水量和TRMM降水量在月尺度和年尺度上均具有较好的相关关系;④ 各流域年均TRMM面降水量均高于气象站点面降水量,且TRMM面降水量相对误差雨季较小,枯季较大;⑤ 各流域TRMM面降水量与气象站点面降水量演变趋势基本一致,南方各流域年降水量均呈减少趋势,北方各流域年降水量均呈增加趋势,全国尺度上年降水量呈微弱的减少趋势。

     

    Abstract: This study evaluated the accuracy and consistency of TRMM rainfall at basin scale across China over the period of 1998 to 2013 based on gauged daily rainfall from 2 257 meteorological stations. The detection accuracy indices (POD, FAR, ACC, and CSI), Pearson correlation coefficient (PCC), and relative error were used. The results show that: ① Detection accuracy of daily TRMM rainfall events decreases from southeast coast to northwest inland in general; ② Average annual rain days from gauged rainfall is significantly larger than that of TRMM; ③ There is a good relation between monthly/annual gauge rainfall and TRMM rainfall at all stations, except for the stations in Northwest China; ④ Average annual rainfall estimated from TRMM is higher than that of the gauged rainfall in all basins, especially in the Southwest China. Relative error of monthly areal TRMM rainfall is smaller in the rainy season and larger in dry season; ⑤ Trends of annual areal TRMM rainfall is in agreement with that of annual areal gauge rainfall in all basins. Annual rainfall demonstrates a decreasing trend in the basins in southern China, and an increasing trend in the basins in northern China. As a result, the annual rainfall overall China shows a slight decreasing trend from 1998 to 2013.

     

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