Poster

IAPSO

JPM05 - Heatwaves in the atmosphere and ocean

Interactions Between Marine Heatwaves, Terrestrial Heatwaves, and Typhoons: A Case of Compound Extreme Events in Summer 2018

Anthropogenic climate change has intensified extreme events such as marine heatwaves (MHWs), terrestrial heatwaves (THWs), and typhoons. When these events co-occur, their combined impacts can amplify environmental consequences, forming compound extreme events. This study investigates the interactions among intense MHWs in the western East Sea since 2000, record-breaking THWs over the Korean Peninsula since 1980, and four consecutive typhoons during July?August 2018. Typhoon Prapiroon (July 4) triggered coastal downwelling in the western East Sea, followed by the simultaneous development of MHWs and THWs driven by an upper tropospheric high-pressure system that enhanced shortwave radiation, suppressed wind speeds, and reduced ocean-atmosphere heat exchange, prolonging their persistence. Typhoons Jongdari (July 29) and Leepi (August 15) reinforced the MHW through coastal downwelling, despite a weakened upper-tropospheric anticyclone. Notably, Typhoon Soulik (August 24) exhibited an unusual pressure drop after crossing the Korean Peninsula, potentially influenced by the underlying MHW. The spatial distribution of THWs was modulated by topography and easterly winds associated with the typhoons, highlighting the intricate interplay between atmospheric and oceanic extremes. These extreme conditions resulted in a doubling of upper 105 m ocean heat content (OHC) and a substantial rise in surface and subsurface temperatures along the east coast of Korea. With the increasing frequency of compound extreme events under climate change, this study underscores the necessity of continuous in-situ observations to improve climate model accuracy. A deeper understanding of these compound interactions is crucial for enhancing predictions of future extreme events and their impacts on marine and atmospheric systems.