Comparison and evaluation of hydrologic performance of satellite, reanalysis and climate model-based precipitation products in the Upper Awash River Basin, Ethiopia

A number of open-source precipitation products offer viable options for hydrological simulation in the absence/limited rain gauge station networks. This study examined the hydrologic performance of reanalysis (CFSR), satellite (CHIRPS) and regional climate model (RACMO22T) based precipitation estimates through Hydrologiska Byråns Vattenbalansavdelning (HBV) model. The performance of these precipitation products were evaluated by the graphical and statistical indices such as coefficient of determination (R2), Nash-Sutcliffe efficiency (NSE), percentage of bias (PBIAS), and mean square error (RMSE) at daily and monthly scales. RACMO22T precipitation product was competent based on all the evaluation statistical indices criteria to simulate flow whereas; CHIRPS and CFSR were unsatisfactory based on the PBIAS and RSME. Flow duration curves indicated that, RACMO22T was able to better estimate high, medium and low flow than CHIRPS and CFSR. The outcome suggested that, RACMO22T is thought to be a more feasible option for the hydrologic simulation than CHIRPS and CFSR in the UARB. Furthermore, the hydrologic performance was improved on monthly scales than daily for all precipitation products. The study therefore, suggested that the use of regional climate model based precipitation products for hydrologic simulation would be of great benefit considering the difficulties in accessing data across and similar basin.