Comparing TRMM-based Multi-Satellite Precipitation Analysis (TMPA) data with ground-based rainfall data

Satellite-based precipitation estimates has seen an increased use as utility in performing hydrologic analyses in areas of the globe where precipitation data is sparse or non-existent. However few studies have been conducted in order to evaluate the performance of satellite-based precipitation estimates when compared to ground-based observations (rain gauges or weather radar). This report evaluates the TRMM-based Multi-Satellite Precipitation Analysis (TMPA) 3B42 Version 6 rainfall estimates with three sources of ground-based precipitation observations; a low spatial density gauge network, a high spatial density gauge network, and NEXRAD Stage III rainfall data. TMPA data was evaluated visually and statistically at the native satellite pixel scale and basin scale for nine years. TMPA data was also evaluated during ten rainfall events which generated significant runoff within the study basin. Results indicate that TMPA data consistently overestimates rainfall at both spatial scales and poorly correlates with all three ground-based observations. Furthermore, TMPA data suffers from falsely detecting rainfall when ground observations do not detect rainfall and the inability to detect rainfall of lower intensities. However, improvements in the performance of TMPA were shown when analyzed during specific storm events. The findings in this report provide insights on the capabilities and limitations of TMPA data for possible users of the product.