Multi-source assessment of uncertainty over the tropical ocean

The tropical ocean, which receives a substantial volume of precipitation and evapotranspiration, has a greater impact on Earth's energy and water balance. Yet, considerable studies have been focused on the Earth's terrestrial precipitation, whereas very little attention has been given to the oceanic region. Despite the advancement of satellite and reanalysis precipitation estimates, relatively few studies explored these estimates over the oceans. In this context, we quantitatively evaluate and inter-compare the state-of-the-art satellite, reanalysis, and merged precipitation products over the tropical oceans. We use a suite of various gridded and well-known precipitation datasets such as the Integrated Multisatellite Retrieval for Global Precipitation Measurement (IMERG), Global satellite Mapping of Precipitation (GSMaP), European Centre for Medium-Range Weather Forecast (ECMWF) Reanalysis v5 (ERA5), and Multi-Source Weighted-Ensemble Precipitation (MSWEP) products to comprehensively estimate the tropical oceanic precipitation and its spatial and temporal variation. In particular, we are looking into the estimates of the total mean precipitation and its inter-annual variation. In addition, the discrepancies among various precipitation estimates are analysed as a function of different spatial and temporal scale to assess their uncertainty over tropical ocean for the first time. This study will provide deep insights into the precipitation characteristic and its spatio-temporal variability across the tropical ocean. Moreover, such information will help to revisit the estimation of the global water budget components in the near future.