Comparative Analysis of the Latest Global Oceanic Precipitation Estimates from GPM V07 and GPCP V3.2 Products

Abstract

Satellites bring opportunities to quantify precipitation amount and distribution over the globe, critical to understand how the Earth system works. The amount and spatial distribution of oceanic precipitation from the latest versions (V07 and the previous version) of the Global Precipitation Measurement (GPM) Core Observatory instruments and selected members of the constellation of passive microwave sensors are quantified and compared with other products such as the Global Precipitation Climatology Project (GPCP V3.2); the Merged CloudSat, TRMM and GPM (MCTG) climatology; and ERA5. Results show that GPM V07 products have higher precipitation rate than the previous version, except for the radar-only product. Within ~65°S-N, covered by all of the instruments, this increase ranges from about 9% for the combined radar-radiometer product to about 16% for radiometer-only products. While GPM precipitation products still show lower mean precipitation rate than MCTG (except over the tropics and Arctic Ocean), the V07 products (except radar-only) are generally more consistent with MCTG and GPCP V3.2 than V05. Over the tropics, (25°S-25°N) passive microwave sounders show the highest precipitation rate among all of the precipitation products studied, and the highest increase (~19%) compared to their previous version. Precipitation products are least consistent in mid-latitude oceans in the Southern Hemisphere, displaying the largest spread in mean precipitation rate and location of latitudinal peak precipitation. Precipitation products tend to show larger spread over regions with low and high values of sea surface temperature and total precipitable water. The analysis highlights major discrepancies among the products and areas for future research.