新一代GPM卫星降水产品在中国的适用性评估

    Toward Reliable Satellite Precipitation for China: Assessing the New Generation of GPM Products

    • 摘要: 全球降水测量计划(GPM)于2024年发布的IMERG V07版本为降水监测提供了新的数据源,然而其在复杂地形和气候条件下的适用性尚未得到充分验证。本研究旨在全面评估IMERG V07版本在中国区域的适用性及其相较于V06版本的改进。基于此,构建了一个包含时空多尺度分析的创新性评估框架,结合699个地面气象站点观测数据和0.25°分辨率的CN05.1高精度网格降水数据集,从站点尺度(2004-2020年)和栅格尺度(2018-2020年)两个层面对IMERG V07与V06(Late产品)进行了系统对比分析。结果表明:在站点尺度上,V07整体性能显著优于V06,整体来看,相关系数平均增加0.05,RMSE、MAE、PBIAS分别降低6.96%,4.18%,18.55%,对小雨(≤10mm/d)和暴雨(≥50mm/d)的探测能力分别提高了4.65%和11.58%;在网格尺度上,V07更准确地刻画了中国降水的空间分布特征,特别是改善了西部干旱区固态及微量降水的识别能力(相关系数整体增加了0.1-0.2),同时提高了东部沿海强降水事件的捕捉精度(RMSE整体降低了30%以上)。研究表明,IMERG V07版本在中国复杂地形和多样化气候条件下展现出优异的适用性,为水文模拟、干旱监测和洪涝预警提供了更可靠的数据支持,同时为卫星降水产品在复杂地形区域的适用性评估提供了新的方法参考。

       

      Abstract: The Global Precipitation Measurement (GPM) mission's release of IMERG V07 in 2024 provides a novel data source for precipitation monitoring, yet its performance across complex terrains and diverse climatic regimes remains to be rigorously evaluated. This study presents a comprehensive assessment of IMERG V07's applicability across China and quantifies its improvements over the preceding V06 version. We developed an innovative multi-scale evaluation framework that integrates observations from 699 meteorological stations with the high-precision 0.25° CN05.1 gridded precipitation dataset, enabling systematic comparison between IMERG Late V07 and V06 at both station scale (2004-2020) and grid scale (2018-2020). Results reveal that V07 demonstrates significant improvements over V06 at the station scale, with an average increase of 0.05 in correlation coefficient and reductions of 6.96%, 4.18%, and 18.55% in RMSE, MAE, and PBIAS, respectively. Notably, V07 enhances detection capabilities for light precipitation (≤10mm/d) and heavy precipitation (≥50mm/d) by 4.65% and 11.58%, respectively. At the grid scale, V07 more accurately captures China's precipitation spatial patterns, particularly improving solid and trace precipitation identification in arid western regions (correlation coefficient increases of 0.1-0.2) and heavy precipitation event detection in eastern coastal areas (RMSE reductions exceeding 30%). Our findings demonstrate that IMERG V07 exhibits superior applicability across China's complex terrain and diverse climate zones, providing more reliable data support for hydrological modeling, drought monitoring, and flood forecasting applications. This study also establishes a methodological framework for evaluating satellite precipitation products in regions characterized by complex topography and climate diversity.

       

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