Evaluation of TRMM 3B42V7 and CHIRPS Satellite Precipitation Products as an Input for Hydrological Model over Eastern Nile Basin

Abstract

Nowadays, precipitation estimations based on satellite products (PESPs) have become an alternative source of sparse rainfall gauge data for various hydrologic applications, especially in scarce data regions like Africa which suffer from a lack of surface monitoring resources. Hence, their accuracy and performances must be evaluated by climate variance, complex topography, and geographical position due to their variation from one region to another. The Blue Nile is considered the crucial tributary of the Nile River which provides the utmost share of the river flow. So, this study aims to evaluate high-resolution PESPs [Tropical Rainfall Measuring Mission product 3B42V7 (TRMM 3B42V7) and Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS)] over the Blue Nile basin (BNB) using categorical metrics [probability of detection (POD), and false alarm ratio (FAR)] and continuous statistical indicators [root mean square error (RMSE), mean absolute error (MAE), relative bias (RE), and correlation coefficient (R)] to assess its capability of rainfall amount detection and event occurrence. Hydrological river basin environmental assessment model (Hydro-BEAM) distributed model is also employed to investigate their capabilities to predict streamflow over the BNB. The hydrological daily and monthly simulations were calibrated and validated at Khartoum and Eldeim station for the period 1998–2007. Further, a hydrological monthly simulation was performed at various stations in the Eastern Nile basin (ENB) within the period 2001–2007 using Hydro-BEAM to appraise the ability of both precipitation products to predict streamflow. Moreover, a trial is made to adopt Hydro-BEAM to consider into the runoff simulation the influence of exiting dams during the simulation periods along the ENB to avoid the uncertainness and inaccuracies in simulation results.