Frequent, Intense and Prolonged Human-Perceived Heat Waves Over the Arabian Peninsula in Recent Decades

The Arabian Peninsula (AP) is experiencing rapid warming and a sharp increase in heat waves (HWs). While previous studies often rely on air temperature thresholds or single-day heat index exceedances, these metrics may not fully capture the cumulative physiological stress and public health risks associated with multi-day human-perceived HWs. This study addresses this gap by employing the percentile-based wet-bulb globe temperature (WBGT), derived from ERA5-Land reanalysis data, as a human-centric metric to evaluate heat stress and characterise human-perceived HWs across the AP during 1950–2025, relative to 1961–1990. Results reveal distinct spatial patterns across the AP, with the highest warm-season heat stress trend over central and northern inland and eastern coastal regions. WBGT exhibits a pronounced seasonal cycle, peaking during July–August and shows a significant increasing trend of 0.176–0.347°C decade⁻¹, with a substantial rise in recent decades. Long-term trends indicate a significant intensification of HW characteristics; HW number (~0.042–0.487 events decade⁻¹), HW days (~0.134–2.446 days decade⁻¹), HW length (~0.003–0.377 days decade⁻¹), HW duration (0.057–0.818 days decade⁻¹), HW magnitude (~0.031–0.048°C decade⁻¹) and HW amplitude (~0.004–0.190°C decade⁻¹), with stronger accelerations in the post-1990s. Wavelet coherence analysis indicates ENSO exhibits the most persistent interannual and decadal coherences with all HW characteristics, confirming it as a key oceanic driver in exacerbating HW activities in AP. These findings highlight the growing impacts of human-perceived HWs across the AP and show the effectiveness of percentile-based WBGT in assessing cumulative physiological strain for supporting heat-risk adaptation strategies.