Comprehensive error analysis of satellite precipitation estimates based on Fengyun-2 and GPM over Chinese mainland

Abstract

The spatial-temporal error characteristics of four mainstream satellite precipitation products developed by China and United States, respectively, including the Fengyun-based (FY-2F and FY-2G) and the GPM-based (IMERG-Late and IMERG-Final) over Chinese mainland were comprehensively analyzed from January 2018 to December 2019. In general, both IMERG-Final and FY-2G perform better at the hourly and daily scales. While the FY-2F product has the relatively worst performance with lowest correlation coefficient (CC) and highest root mean square error (RMSE) values. In particular, FY-2F has considerable total bias and missed precipitation errors in summer when compared to other three precipitation products. As for winter, the IMERG product suites exhibit significantly overestimation in north-central region of China, while an opposite underestimation occurred in the Fengyun products. Among the four precipitation estimates, IMERG-Final and FY-2G have the lowest normalized-RMSE (NRMSE) at the elevation range of 100–300 m and 300–500 m at daily scale, respectively. The performance at the hourly scale was found to be similar for IMERG-Final and IMERG-Late, but both of which are slightly superior to FY-2G across the elevation ranges. In terms of the detectability for different rain intensities, the IMERG products performed best at higher rain rates, while the Fengyun-based precipitation estimates are superior to IMERG at relatively lower rain ones. The assessment results reported here will provide some valuable feedbacks for algorithm developers of Fengyun products, and enable data users to further understand the error characteristics and potential deficiencies of Fengyun precipitation estimates.