Temporal assessment of the GPM satellite rainfall products across extremely arid regions

Abstract

Measuring rainfall precisely is always challenging due to its high variability, particularly in arid regions. Arid regions such as the Kingdom of Saudi Arabia (KSA) and the United Arab Emirates (UAE), suffer from rainfall scarcity and high variability of rainfall distribution. Thus, accurate monitoring and management of rainfall are one of the countries’ priority to ensure proficient water resources management. This study validates the accuracy of the GPM IMERG rainfall products over the KSA and UAE to detect the large rainfall events over the period from 2015 to 2017 (two seasons). A temporal assessment was carried out to evaluate the performance of the GPM satellite to detect the rainfall events. The results showed that, for satellite detection, all of the three IMERG near real-time and post-real-time products had a significant detection accuracy. On the other hand, the error indicators showed that the final-run-product had a relatively low estimation error and bias compared with the other IMERG products. Overall, the results revealed that the IMERG final-run-product have the potential to serve as a consistent product to supplement ground measurements, particularly in regions with insufficient coverage by rain gauges. This study is considered one of the earliest evaluations of the GPM IMERG products in the region. Thus, the findings could be used to enhance the upcoming IMERG algorithms associated with the arid regions.