Utility of satellite precipitation products for drought monitoring (case study: southwestern regions in Iran)

Abstract

Satellite precipitation products (SPPs) with high spatial and temporal resolution are considered as a new source of precipitation data to monitor drought events, particularly for data-sparse areas. However, they should be extensively validated against ground-based data before their utilization. In this study, three (SPPs) including Integrated Multi-satellite Retrievals for GPM (GPM IMERG), Climate Prediction Center morphing technique (CMORPH), and PERSIANN Dynamic Infrared–Rain Rate (PDIR-Now) are examined extensively on multiple spatiotemporal scales in precipitation estimation as well as their utility for drought monitoring across the southwestern Iran over 2001–2021. The Asfezari gridded precipitation data developed from a dense of rainfall gauges were used as the reference dataset. The results suggest that IMERG Final Run Version 7 (IMERG-F hereafter) outperforms the other products in representing spatiotemporal patterns of precipitation followed by PDIR-Now and CMORPH based on the statistical indices including relative bias (RB), correlation coefficient (CC), and root mean square error (RMSE). CMORPH product substantially underestimates precipitation values over the elevated regions. The results also suggest that IMERG-F shows the best performance with ground-based data for drought monitoring particularly for the 6 month SPI time scale. IMERG-F was also superior in tests involving correct, false, and missing drought detection. Ultimately, our results show that satellite-based precipitation products can be quite useful in drought monitoring, particularly in areas like southwestern Iran where droughts are frequent and may become more frequent in years to come. © The Author(s), under exclusive licence to Springer Nature B.V. 2024.