EVALUATING SATELLITE PRECIPITATION MEASUREMENTS: FROM CURRENT-GENERATION TRMM TO NEXT-GENERATION GPM

Precipitation is an important component of the water cycle, as it replenishes the groundwater, lakes, and rivers on earth. Water resource management relies heavily on accurate precipitation measurements in order to monitor the freshwater resources. Precipitation measurements obtained from rain gauge and ground radar system are very helpful, but limited by their spatial coverage and availabilities. With the technological advances in earth observing instrumentation, satellites are developed to monitor the intensity and distribution of precipitation from space. However, the quality of satellite precipitation measurements is a vital factor in the decision to use these measurements for hydrologic applications. This study evaluates the performances of NASA’s current-generation and next-generation satellite precipitation measurements: Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA), and the Global Precipitation Measurement (GPM) Integrated Multi-satellitE Retrievals for GPM (IMERG). These two satellite precipitation measurements are compared to the ground reference NOAA stage IV multi-sensor composite rain analysis in the summer of 2016 and winter of 2016-2017 over the continental United States. The abilities to capture the storm systems are examined for TMPA and IMERG using an object-based verification approach, which focuses on the spatial and geometric patterns of precipitation events. The results suggest that IMERG performs slightly better than TMPA on depicting the spatial characteristics of storm systems.