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台风“烟花”影响浙江期间GPM卫星降水产品的评估及订正

Evaluation and correction of GPM satellite precipitation products during Typhoon "In-Fa" affecting Zhejiang

  • 摘要: 为了解和提高GPM (Global Precipitation Measurement)卫星降水产品在台风降水过程中的表现和质量,基于地面气象观测站雨量资料,分别采用逐步订正法和最优插值法订正卫星反演降水产品,并从不同时间尺度评估2021年台风“烟花”登陆浙江期间GPM (第六版)反演产品在订正前后的监测能力。结果表明:未订正的GPM反演降水产品未能描述浙江省内高大地形处的强降水中心,对过程降水量低估约45%,主要源于对浙江东北部降水大值区的低估,降水分级检验显示,未订正的GPM产品除对小雨有较好反映能力外,其余各级别探测能力均较差;经逐步订正法和最优插值法分别订正后,反演产品的过程累计、逐日及逐时降水的评估结果均有提升,且逐步订正法订正后效果更优,最优插值法订正后对实际降水略有高估,两种方法订正后的产品不仅可描述与高大地形相关的强降水中心,也可反映大暴雨和小时雨强大于23 mm·h-1的强降水。

     

    Abstract: To understand and improve the performance and quality of Global Precipitation Measurement (GPM) satellite-derived precipitation products during the typhoon process, with gauge observations from ground meteorological stations, this study used the successive and optimal interpolation correction methods to correct the GPM precipitation products. The performance of GPM products (Version 6) before and after the correction at different time scales are evaluated with the products during the two landfalls of Typhon"In-Fa". Results show that the original GPM precipitation products fail to describe the strong rainfall center over the high terrain area, which significantly underestimates the precipitation by approximately 45%. This is mainly due to the underestimation of the large values in the northeast region of Zhejiang province. The analysis of precipitation classification inspection suggests that the uncorrected GPM satellite-derived products have good capability for light rain, but poor for other rainfall levels. After the successive and optimal interpolation correction, significant improvement can be found in the cumulative, daily, and hourly rainfall products. The products with successive correction are better, while the product with optimal interpolation slightly overestimates the actual precipitation. The corrected GPM products can not only describe the heavy precipitation center related to the terrain but also reflect heavy rainstorms and heavy precipitation with hourly rainfall intensity greater than 23 mm·h-1.

     

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