[A-CG33] 中緯度大気海洋相互作用

[ACG33-08] Decadal cooling trend of the East China Sea in the early 21st century

*宮本 歩¹、中村 尚¹、小坂 優¹ (1.東京大学先端科学技術研究センター)

キーワード：東シナ海、十年規模変動、ストームトラック活動、冬季東アジアモンスーン、下層雲

The East China Sea (ECS) has significant impacts on the surrounding climate and ecosystem. The ECS is warming much faster than the other oceans under anthropogenic radiative forcing. In the early 21^st century, however, the ECS exhibits a significant year-round cooling trend. Here, we investigate this decadal cooling trend with a particular focus on atmospheric forcing. We find that the mechanism is seasonally distinct. In winter, the enhanced East Asian winter monsoon associated with the Warm-Arctic Cold-Eurasian (WACE) pattern brings near-surface cold-air advection, promoting turbulent heat loss from the ECS. In spring, the synoptic eddy activity augments scalar wind speed, thereby reinforcing the turbulent heat loss from the ECS. This enhanced synoptic eddy activity is remotely forced by the cooling trend of the equatorial central Pacific. In summer, low-cloud feedback further acts to promote the ECS cooling trend by reducing shortwave heating.