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

On 20 July 2021, an abrupt rainstorm occurred in central and northern Henan province, China and killed at least 302 people. 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 these 10 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.