Evaluation of Era5, and Space-Based Precipitation Estimation Over Awash River Basin, Ethiopia

Precipitation is critical to human life, especially in developing nations like Ethiopia, where rain-fed agriculture supports the economy and food security. High variability and limited precipitation data are critical problems in the Awash River Basin. In this regards, high-resolution satellite-based precipitation estimation can fulfill these data gaps. In this study, ERA5, CHIRPS, IMERG-V06, and PERSIANN-CDR were compared with gauged observations from 24 meteorological stations between 2001 and 2013.Using pixel-to-point pair-wise comparison, systematic shortcomings in satellite rainfall estimates were identified. Accordingly, CHIRPS outperform with R
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values from 0.95 at Bole to 0.48 at Assaita and RMSE values from 57.82 mm at Tulu Bolo to 28.82 mm at Dupity whereas PERSIANN-CDR and ERA5 poorly performed. The performance of each products declines from highlands to lowlands. This suggests that topographic effects should be considered when using these products for hydrologic, climate change, and extreme event forecasting.