[A-CG32] Extratropical oceans and atmosphere

[ACG32-08] Warming of the Kuroshio Current over the last four decades has intensified the Meiyu-Baiu rainband

*YUXIANG QIAO¹, Hirohiko Nakamura¹, Tomohiko Tomita² (1.Kagoshima University, 2.Kumamoto University)

In recent decades, rise of sea surface temperature (SST) in the Kuroshio region of the East China Sea (ECS), which is associated with global warming, has attracted considerable attention. Despite its relevance to air-sea interaction phenomena, the atmospheric consequences of this SST increase remain largely unexplored. Using the ERA5 reanalysis dataset in conjunction with a moisture budget analysis, we found that during 1979–2022, warming in the ECS-Kuroshio has contributed to the intensification of the East Asian Meiyu-Baiu rainband in June. This intensification is attributed to augmented wind convergence in the low-level free troposphere (950–700 hPa). Importantly, the atmospheric responses to ECS-Kuroshio warming penetrated the deep troposphere (to approximately 300 hPa), suggesting an enhancement of deep convection. Furthermore, ECS-Kuroshio warming likely strengthened the overlying atmospheric low pressure, resulting in wind convergence enhancement. The findings clarified the important role of the ECS-Kuroshio in driving East Asian climate change amid global warming.