Evaluation of latest GPM-Era high-resolution satellite precipitation products during the May 2017 Guangdong extreme rainfall event

Abstract This study evaluates the performance of latest version 5B (V5B) Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (IMERG) Final Run products during a 60-year return extreme precipitation storm on 7 May 2017 over southern China with gauge observations as the reference dataset. Version 4 (V4) Global Satellite Mapping of Precipitation (GSMaP) products and quantitative precipitation estimates derived from a local ground-based S-band dual polarization weather radar (radar, hereafter) were used for parallel comparisons. The satellite-only products (IMERGUncal and GSMaP_MVK) and gauge-corrected products (IMERGCal, GSMaP_Gauge) were selected for this study. The results showed that: 1) GSMaP_MVK, IMERGUncal, GSMaP_Gauge and IMERGCal generally capture the spatio-temporal patterns of storm-accumulated rainfall with correlation coefficient (CC) values about 0.76, 0.70, 0.68 and 0.72, respectively, while radar was well correlated with gauge measurement (CC about 0.94); 2) The GSMaP_Gauge (−19.38%), IMERGCal (−40.23%), GSMaP_MVK (−57.12%), IMERGUncal (−58.77%) satellite-based precipitation products all underestimated the storm-accumulated precipitation, while ground radar overestimated by 27.48%; 3) Both IMERGCal and IMERGUncal outperformed their GSMaP counterparts in capturing the time-series with much higher CC (0.50 vs. -0.21, 0.51 vs. 0.17); 4) Among the satellite-based QPE products, when the rainfall rates are