高分辨率卫星对“21·7”河南特大暴雨监测能力分析

Analysis of the monitoring ability of high-resolution satellites for the"21·7"heavy rain in Henan

2021年7月20日河南中北部突降暴雨,造成至少302人遇难,这类极端降水事件会对社会经济发展和人类生产、生活造成较大的影响,因此,准确监测这类暴雨事件至关重要。采用定性和定量方法综合评定了主流的10种高分辨率卫星降水产品(CMORPH-Raw、CMORPH-RT、PERSIANN-CCS、GPM IMERG-Early、GPM IMERG-Late、GSMa P-Now、GSMa P-NRT、FY-2F、FY-2G和FY-2H)在本次极端暴雨事件中的适用性,并分析了这10种产品对不同级别降水的监测能力。结果表明,这10种卫星降水产品均可以较为准确地再现出暴雨中心位于河南中北部的空间分布特征,但是所有卫星降水产品均较大程度低估了暴雨中心的降水量。随着降水等级的升高,各类卫星降水产品的命中率下降,TS评分降低,误报率升高。CMORPH-RT对于暴雨量的捕捉能力强于CMORPH-Raw,且对暴雨过程的捕捉能力也更强;GPM IMERG-Late的准确度较GPM IMERG-Early有较大提高;相比于GSMa P-Now降水产品,GSMa P-NRT的准确度较高;PERSIANN-CCS和FY-2F的效果较差,不能捕捉此次极端暴雨事件。对本次暴雨事件而言,CMORPH-RT的效果最好,可以准确捕捉暴雨中心而且量值也与观测最为接近;融合红外和被动微波信息的卫星降水效果优于仅使用红外信息的降水产品,而且卫星反演算法和融合被动微波数据的多少对卫星降水的准确度有较大影响。

On 20 July 2021,an abrupt rainstorm occurred in central and northern Henan province,China and killed at least 302people.Such kind of extreme precipitation events have great impacts on social and economic development and human lives.Therefore,accurate monitoring of such rainstorm events is crucial.Qualitative and quantitative methods are used to comprehensively evaluate 10 high-resolution satellite precipitation products(CMORPH-Raw,CMORPH-RT,PERSIANN-CCS,GPM IMERG-Early,GPM IMERG-Late,GSMaP-Now,GSMaP-NRT,FY-2F,FY-2G and FY-2H)of this extreme rainstorm event,and the ability of these10 products to represent different levels of precipitation are also analyzed.The results show that these 10 satellite precipitation products can capture spatial distribution characteristics of the rainstorm that is located in central and northern Henan,but all satellite precipitation products underestimate the precipitation value at the rainstorm center.As the precipitation level increases,the hit rate and the TS score decrease,and the false alarm rate increases.CMORPH-RT has a better ability to capture the rainstorm than CMORPH-Raw,and shows the ability to capture rainstorm process.GPM IMERG-Late is more accurate than GPM IMERG-Early.Compared to GSMAP-Now,the performance of GSMAP-NRT enhances.PERSIANN-CCS and FY-2F show a poor performance and cannot capture this extreme rainstorm event.Among them,CMORPH-RT has the best performance,since it accurately captures the rainstorm center and magnitude that are the closest to observations.In general,satellite precipitation products that integrate infrared and passive microwave information are better than the products that only use infrared information.The satellite precipitation retrieval algorithm and the amount of passive microwave data have a great impact on the accuracy of satellite precipitation products.