Hydrological performance evaluation of multiple satellite precipitation products in the upper Blue Nile basin, Ethiopia

Abstract

Study region: Ethiopia, upper Blue Nile. Study focus: This study evaluates hydrological performance of multiple globally available precipitation products in the data scarce region of the upper Blue Nile basin over multi-scales (1656–199,812 km2) focusing on multi-year (2000–2012) for daily simulation. Grid based, fully distributed hydrological model Coupled Routing and Excess STorage (CREST) is calibrated using in-situ observed rainfall data. The evaluation compares five precipitation products of gauge adjusted Climate Prediction Center Morphing Technique (CMORPH), Tropical Rainfall Measuring Mission (TRMM) Multi-Satellite Precipitation Analysis 3B42 version 7 (TMPA), ERA-Interim (ERAI), Global Precipitation Climatology Centre (GPCC) and Multi-Source Weighted Ensemble Precipitation (MSWEP). New hydrological insights for the region: Performance results indicate that the MSWEP precipitation shows consistently better performance than from the rest of precipitation products. This global precipitation product can be a priori alternative source of data for various water resources applications in the upper Blue Nile basin for its predictive ability and the length of data availability which the product has an advantage over the satellite products. However, the product needs improvement to estimate the total annual flow volume of the observed flow for the three nested watersheds to perform close to the gauged rainfall. This by no means undermines the potential benefits of the rest products for different watersheds and time scale. Keywords: CREST, Blue Nile, Hydrologic modeling, Satellite and reanalysis, Precipitation