Performance Assessment of Multiple Satellite Rainfall Products in the Levant Region

Abstract

The availability of precipitation data from in situ stations faces various challenges including quality, temporal resolution, irregular spatial distribution, and scarcity in many regions. This is particularly true for the West Bank. Hence, the need to identify alternatives sources is a priority as high quality precipitation estimates are essential for accurate hydrological applications. This study assesses the reliability of four satellite precipitation products (IMERG Final Run, PDIR-Now, CCS-CDR, CMORPH) against 442 in situ rainfall stations across Israel (354) and Palestine (88). These four satellite products, with spatial resolutions ranging from 4 to 10 km, were evaluated at the daily timescale to maximize the number of in situ stations available. The analysis reveals that IMERG outperforms the other products, with a mean $R^2$ of 0.33 and a Probability of Detection (POD) of 0.7, without any adjustments. The study also examined the influence of elevation on satellite performance, noting that while IMERG consistently excels in most indices, PDIR has lower Mean Absolute Errors at lower elevations. The results highlight a disparity in performance between the Israeli and Palestinian in situ stations. Overall, IMERG emerges as the most reliable satellite-based estimate for the Levant region, proving effective across different elevations, climatic zones, and rainfall intensities.