Spatial and Temporal Dynamics of Drought, Heatwave and Compound Extremes in Saudi Arabia From 1984 to 2023: A Comprehensive Analysis

Abstract

Climate extremes are intensifying in arid regions, yet comprehensive assessments of compound drought–heatwave (CDHW) events remain limited in the Arabian Peninsula. This study presents the first station-based analysis of drought, heatwave and CDHW dynamics across Saudi Arabia over four decades (1984–2023), using daily observations from 23 meteorological stations. We identified droughts using the Effective Drought Index (EDI ≤ −1.0), defined heatwaves as ≥ 3 consecutive days exceeding the 90th percentile of daily maximum temperature and classified CDHW events when both conditions co-occurred. Trends were assessed using the modified Mann–Kendall test, with spatial patterns mapped via inverse distance weighting interpolation. Results reveal contrasting trends among event types. Mean annual drought duration reached 189.6 days in northern and central regions, with a non-significant national trend of +0.67 days year⁻¹ (p = 0.148). Heatwaves intensified significantly at +0.56 days year⁻¹ (+5.6 days decade⁻¹; p < 0.001), with 74% of stations showing upward trends. Compound events also increased at +0.08 days year⁻¹ (+0.8 days decade⁻¹; p = 0.031), with 2019 recording the most severe conditions (> 11 mean days). Decadal analysis shows drought intensification peaked during 2004–2013 (mean + 41.38% relative to 1984–1993 baseline), while heatwave increases were strongest during 2014–2023 (mean + 16.52%). Probability density analysis indicates a shift towards longer-duration extremes in recent decades, with maximum observed durations of 125 days for droughts, 50 days for heatwaves and 15 days for CDHW events. These findings demonstrate robust intensification of heatwaves and compound extremes, with central and northern regions experiencing the greatest vulnerability. The escalating frequency and severity of compound events underscore the need for enhanced monitoring systems and targeted adaptation strategies aligned with Saudi Vision 2030 climate resilience objectives.