双偏振雷达评估IMERG对不同类型降水的观测精度

Using Dual-polarization Radar to Evaluate Accuracy of GPM/IMERG in Different Types of Precipitation Process

采用地面雨量计校准后的南京信息工程大学(Nanjing University of Information Science&Technology,NUIST) C波段双偏振(C-band Dual-Polarization Radar,NUIST-CDP)雷达降水估测数据,研究全球降水观测(Global Precipitation Measurement,GPM)计划多星融合降水产品(Integrated Multi-satellite Retrievals for GPM,IMERG)对苏皖地区梅雨、台风和飑线等不同类型降水观测精度,结果表明,(1)梅雨降水过程中,IMERG的累计降水量整体大于NUIST-CDP的累计降水量;(2)台风降水过程中,IMERG一定程度上低估了累计降水量较大时的降水结果;(3)IMERG不能很好地观测到飑线降水的空间结构,几乎没有观测到这次降水过程中的强降水区域。

The precipitation estimation ability of the integrated multi-satellite retrievals for Global Precipitation Measurement(GPM/IMERG) is refined and evaluated in the study for Meiyu,typhoon and squall line precipitation,using the measurements from C-band dual-polarization radar from the Nanjing University of Information Science & Technology(NUIST-CDP).The ground-based gauges are used to calibrate the radar data.The main conclusions are:(1) IMERG overestimates the cumulative precipitation estimated by NUIST-CDP during Meiyu precipitation.(2) During typhoon precipitation,when the cumulative precipitation estimated by NUIST-CDP is large,IMERG greatly underestimates the precipitation of NUIST-CDP.(3) IMERG performs poorly during squall line precipitation because it hardly observes heavy precipitation.