From TRMM to GPM, how do improvements of post/near-real-time satellite precipitation estimates manifest?

With the end of Tropical Rainfall Measuring Mission (TRMM) era, its successor Global Precipitation Measurement (GPM) aims to provide a new generation satellite precipitation estimates (SPE) with higher spatiotemporal resolution and wider spatial coverage. As representative retrieval algorithms for GPM TRMM eras, it is necessary compare Integrated Multi-satellite Retrievals (IMERG) Analysis (TMPA) investigate improvements SPEs from GPM. This study analyzes post/near-real-time TMPA IMERG over Mainland China April 2014 March 2018 at daily scale, using observations 510 meteorological stations as reference. A very comprehensive evaluation system, which contains four indicators continuous metrics, categorical error components, systematic random errors adopted in this study. Besides, patterns distribution, temporal pattern, intensity overall metrics are applied illustrate each indicator's performance. The results show that products have lower RB RMSE CC than greatly reduce three components (hit bias, missed precipitation, false precipitation). Furthermore, present capability capture events correctly generally products. However, there still rooms improve, such alarm ratio (FAR) more relatively low rain rates, 25% IMERG-E (IMERG “Early Run” near-real-time SPE) compared TMPA-RT (TMPA SPE). In addition, we find gauge adjustment GPCC not effective way improve detecting China. provides some valuable information on transition IMERG, may advance algorithm's development hydrometeorological applications.