Influence of marine heatwaves on tropical cyclones affecting the Korean Peninsula

This study investigates the impact of marine heatwaves (MHW) on tropical cyclones (TCs) affecting the Korean Peninsula. TC events occurring between June and October from 1982 to 2023 were analyzed. The categorization of MHW TCs or non-MHW TCs was determined based on whether they passed through MHW-affected ocean regions prior to reaching the Korean Peninsula. The results of this study demonstrate that MHW TCs exhibit stronger maximum sustained winds when approaching the Korean Peninsula than non-MHW TCs. This intensification effect was statistically significant only for strong TCs with maximum wind speeds exceeding 33 ms -1 . Analysis of rainfall shows that MHW TCs produce significantly more precipitation, with peak rainfall rates nearly eight times higher than those of non-MHW TCs. Our analysis of the physical mechanisms involved shows that high sea surface temperatures during MHWs increase surface saturation specific humidity, resulting in enhanced air-sea moisture disequilibrium. Combined with strong low-level winds in intense TCs, this leads to increased ocean-to-atmosphere latent heat flux and strengthened moisture flux convergence near the TC core. These processes sustain deep convection and reinforce TC intensity and rainfall. These findings suggest that MHWs can substantially amplify the wind and rainfall hazards posed by strong TCs approaching the Korean Peninsula. This indicates an increased risk in future climate warming scenarios characterized by more frequent and intense MHWs.