Performance of Different Global Precipitation Measurement IMERG Satellite Products over Saudi Arabia

Precipitation is a major component of the hydrologic and energy cycles. Measurement of precipitation provides one of the primary inputs for hydrological, meteorological and climate models, which are used to predict different natural hazards such as landslides, floods, and droughts. Thus, the measurements of precipitation should be more representative of the true precipitation. Many approaches and techniques are used to collect precipitation data. Recently, hydrometeorological and climatological applications of satellite precipitation products have been witnessing a significant leap with the emergence of the latest satellite products, namely the Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (GPM) mission (IMERG) products, which can be utilized to estimate and analyze precipitation data. This study focuses on the validation of the IMERG satellite rainfall products: the early, late and final runs, using ground-based rain-gauge observations over all regions of Saudi Arabia for the period from October 2015 to April 2016 ta daily time scale. The accuracy of each IMERG product was assessed using six statistical performance measures to conduct three main evaluations: regional, event-based and station-based. The results indicate that the early run product performed well in the middle, eastern and some of the western parts of the country, while for the other parts, the satellite estimates fluctuated between overestimation and underestimation. The late run product showed an improvement in the accuracy of the southern and western parts; however, over the northern and middle parts, it showed a relatively high error. The final run product revealed a significant improvement of precipitation estimation and success to obtain a high accuracy over most parts of the country. The study provides an early assessment of the performance of the GPM satellite products over the Middle East.