Spatiotemporal trends of compound extremes and their impacts in Southeast Asia from 1983 to 2022

Compound extremes (CEs) pose escalating threats to Southeast Asia (SEA)’s densely populated and economically dynamic communities. This study analyses spatiotemporal trends in three predominant CE types: compound precipitation-wind extremes (CPWEs), dry spell and heat extremes (DSHEs), and humid heatwave extremes (HHWEs). By utilizing multiple widely used datasets, we establish reliable benchmark event sets that are not biased by a single source. Our analysis reveals distinct subregional patterns of CE impacts. CPWEs predominantly occur along coastal areas, with seasonal hotspots shifting in response to monsoonal wind dynamics. DSHEs and HHWEs are concentrated in continental SEA, often compounding during peak seasons. Statistically significant rises in annual HHWE impacts are detected, with decadal increases of 0.4–6.6% in both duration and spatial extent. This is followed by 0.5–3.8% decadal increases in CPWE impacts. Moreover, large-scale climate drivers, including the El Niño-Southern Oscillation and the Indian Ocean Dipole (IOD), amplify heat-related CE impacts by 7.6–91.7% during El Niño or when combined with a positive IOD phase, while reducing them by 15.9–73.2% during La Niña. This consistent assessment of subregional differences in CE hazards and their response to atmospheric circulation shifts can inform decision-making for mitigation and adaptation strategies across SEA.