Spatio-temporal Validation of Multi-Source Satellite Rainfall Products in the Upper Tekeze-Atbara Basin, Ethiopia

Abstract Obtaining accurate and reliable rainfall information is crucial for regional water resource management. However, in developing countries like Ethiopia, rainfall measurements are characterized by sparse, temporally inconsistent, and unavailability of updated data. Due to these reasons, the spatio-temporal characteristic of rainfall in the study area of Ethiopia is poorly understood. To overcome these limitations, the recently developed satellite derived rainfall products have become an alternative sources of rainfall data. Therefore, this study was conducted to validate the spatio-temporal performance of satellite rainfall products (PERSIANN_CDR, CHIRPS, and TMPA3B42) over Upper Tekeze-Atbara River Basin. The prediction performance of the satellite rainfall products was evaluated using different statistical measures and spatial comparisons for the period from 2007 to 2017. The result showed that PERSIANN_CDR had very low PBIAS than other products. The PERSIANN_CDR had a slightly overestimation tendency while the CHIRPS and TMPA3B42 considerably overestimated observation rainfall. The PERSIANN_CDR performed well for kiremt, belg, and bega season rainfall, with the lowest RMSE value of 2.9, 1.4, and 0.8 mm/day, respectively. On the contrary, TMPA3B42 poorly performed for kiremt, belg, and bega seasons with the largest RMSE value of 3.1, 1.9, and 1.1 mm/day, respectively. The PERSIANN_CDR and TMPA 3B42 had good skill to detect observed rainfall, while the CHIRPS had the lowest detecting skill during all seasons. Overall, the finding of this validation study showed the potentials of the PERSIANN_CDR product to be used for various operational applications such as rainfall pattern and variability study in the Upper Tekeze-Atbara River Basin in Ethiopia.