Future Meiyu Precipitation Change and Atmospheric River Impacts Across East Asia: Regional Disparities and Risks

Abstract Abnormally extreme Meiyu precipitation in East Asia is significantly influenced by atmospheric rivers (ARs), which can trigger severe natural disasters and great socioeconomic losses. Yet projected changes in Meiyu rainfall and its coupling with ARs remain uncertain. This study utilizes the Coupled Model Intercomparison Project phase 6 models under Shared Socioeconomic Pathway 2–4.5 (SSP245) and 5–8.5 (SSP585) scenarios to analyze four land regions with substantial Meiyu rainfall: Korean Peninsula (KR), South Japan (JP), lower Yangtze River basin (LYRB), and South China coast with Taiwan Island (SCTW). Under both scenarios, mean and extreme Meiyu precipitation increase with marked regional variations. Specifically, under the SSP585 scenario, SCTW experiences the largest increase (>40%), while JP exhibits the weakest amplification in Meiyu rainfall by the end of this century. The frequency of hazardous rainfall events is anticipated to increase substantially, particularly over KR and SCTW. AR landfalls are projected to intensify by approximately 70% over KR and LYRB and to nearly double over SCTW, with a smaller increase over JP, leading to an enhancement in the local AR‐related wet‐day and extreme precipitation frequency, while the efficiency of AR precipitation may reduce. Attribution analyses suggest thermodynamic moistening (vertical moisture term) broadly dominates precipitation increases, partly offset (strengthened) by the vertical circulation effect in the LYRB and JP (KR and SCTW). These findings underscore the challenges of climate risk management under global warming, and the mitigation (SSP245) scenario markedly reduces intensification and risk, highlighting the urgent need for climate protection measures in East Asia.