Assessment of Drought Severity and Their Spatio-Temporal Variations in the Hyper Arid Regions of Kingdom of Saudi Arabia: A Case Study from Al-Lith and Khafji Watersheds

The goal of this study is to calculate meteorological drought using the Standard Precipitation Index (SPI) and Evapotranspiration (SPEI) for Al-Lith Khafji basins Kingdom Saudi Arabia (KSA) from 2001 2020. in situ (rain gauges, RGs) Integrated Multi-satellite Retrievals GPM (IMERG) data are used current study. monitored across AL-Lith watersheds. climate watershed like some extent. Still, due complex terrain, receives relatively high precipitation has a higher average temperature than watershed. Results show that total periods observed 166 139 months based on SPEI SPI multiple time scale (1, 3, 6, 12 months) watershed, respectively. While, SPI, experienced 129 72 months, This finding indicates SPEI-calculated more severe persistent both watersheds SPI-calculated drought. Additionally, correlation coefficient (CC) between investigated; very low at smaller scale. CC values 0.86 0.93 0.61 0.79 SPEI-1/SPI-1 SPEI-3/SPI-3. However, significant temporal scales, i.e., 6 with 0.95 0.98 0.94 Overall, compared performance IMERG RGs monitor drought, performed well during period. Therefore, recommends application monitoring data-scarce regions KSA. Furthermore, estimates long-lasting because factor it considers.