Applicability evaluation and error analysis of TMPA and IMERG in Inner Mongolia Autonomous Region, China

Precipitation data accuracy is a critical element of global meteorological observations. The applicability of the Tropical Rainfall Measuring Mission (TRMM) Multi-Satellite Precipitation Analysis (TMPA) and the latest Global Precipitation Measurement Program (GPM) Multi-Satellite Retrieval (IMERG) Precipitation Analysis Product (SBPP) was assessed using precipitation data from ground observations in Inner Mongolia Autonomous Region. The effects of precipitation intensity, season and topography on the accuracy of precipitation estimation were analyzed. At the daily scale, the SBPP could be used to estimate precipitation over a wide range of scales. The results showed that the TMPA daily precipitation product correlation (CC = 0.51) and precipitation capture (probability of detection (POD) = 0.545) were slightly less capable under the influence of complex topography and uneven precipitation, but IMERG (CC = 0.71; POD = 0.762) greatly improved the detection of precipitation, and the IMERG (mean RB = 9%) algorithm mitigated the TMPA (mean RB = 14%) overestimation. The correlation between TMPA (CC = 0.91) and IMERG (CC = 0.93) monthly products was significant. Overall, IMERG detected precipitation and monsoonal precipitation more accurately than TMPA in complex topographic landscapes and provided reliable precipitation estimates for future hydrometeorological studies in Inner Mongolia Autonomous Region. However, the high-intensity precipitation hit rate was low, and further error correction is required for extreme precipitation applications.