No abstract

Two near-real-time and one post-processing products from the Integrated Multi-satellite Retrievals for Global Precipitation Measurement Mission (GPM IMERG) were evaluated during the period from 2016 to 2018 in the wet seasons (June-November) over the Sichuan Basin, China. Results indicated the following: (1) The three products could generally replicate strong precipitation well; however, significantly large biases were observed when detecting weak precipitation. (2) All three products replicated summer precipitation more accurately than autumn precipitation. The IMERG "early run" product (IMERG-E) largely underestimated precipitation in the wet season, while the "latter run" (IMERG-L) and "final run" products (IMERG-F) could counteract this to a certain degree. (3) IMERG-F captured weak, moderate, and strong precipitation well during the wet season, and IMERG-E showed excellent potential in detecting different precipitation intensities. All the three products could replicate the diurnal cycle of the wet season precipitation. The findings of this study can facilitate the application of IMERG products in regions with complex topography and have also highlighted the potential of IMERG-E for rapid early warning and forecast systems.

 All the precipitation estimations had substantial overestimation in the northwest of the basin, and the major error sources are false and hit precipitation  The calibration of GPCC monthly observation intensifies the overestimation of hit and false precipitation  The leading estimation error sources of summer moderate precipitation are missed and hit precipitation