Assessment of Changes in Heatwave Aspects over Saudi Arabia during the Last Four Decades

Abstract

Heatwave (HW) number (HWN), frequency (HWF), duration (HWD), magnitude (HWM), and amplitude (HWA) are key aspects for interpreting and understanding HW characteristics worldwide. Most previous HW studies over the Kingdom of Saudi Arabia (KSA) focused only on the temperature extremes, so this study aims to assess the decadal changes, anomalies, and spatiotemporal variations in the five HW aspects over KSA during the last four decades (1982–2021) using the ClimPACT2 software. Daily gridded (0.25° × 0.25°) maximum (TX) and minimum (TN) temperatures from the ECMWF-ERA5 reanalysis dataset were used to compute these heat wave (HW) aspects. The HW aspects were derived in ClimPACT2 using the Excess Heat Factor (EHF), the 90th percentile of TX (TX90), and the 90th percentile of TN (TN90), all based on the reference climate period of 1982–2011. The results showed that the decadal sum and anomaly of the five HW aspects increased gradually during the last four decades (1982–2021). The three indices showed that the maximum decadal sum of HWN (42 events), HWF (255 days), and HWD (145 days) occurred in the last decade. Additionally, the last decade has the maximum decadal sum of HWM (175–463 °C) and HWA (189–471 °C) as derived from TX90 and TN90, which is confirmed by EHF, with ranges of 7–58 and 15–185 °C2, respectively. Finally, the periods 2015–2021 and 1984–1986 recorded the highest and lowest values of annual HW aspects, respectively, across the study period.