17:15 〜 19:15
[AOS21-P11] 黒潮大蛇行に関連した駿河湾の海上風の線形トレンド
キーワード：線形トレンド、海上風、黒潮大蛇行、GPV-MSMデータ、駿河湾
Linear trends of surface winds were investigated in Suruga Bay, which faces the Pacific Ocean, using surface wind data (GPV-MSM data) provided by Japan Meteorological Agency (JMA) in the period from 2007 to 2022. Westerly winds with speed of about 2 m s-1 blew over area from the central part to the mouth of the bay during this period. The westerly winds were locally deflected northward and weakened in the inner bay, forming a cyclonic circulation in the whole bay. Analyses of annual mean fields revealed that the westerly winds intensified with periods of 2-4 years from the bay mouth to its central region. Notably, the southerly winds in the inner bay markedly decreased after 2019. This weakening of the southerly winds was related to linear trends of the surface winds; that is, northerly winds tended to strengthen from the western to the central part of the bay. Accompanying the strengthening of the northerly winds, the cyclonic circulation intensified with the shift of its center to the eastern part of the bay. Additionally, the Kuroshio, flowing east-northeastward along the southern coast of the Japanese islands, has taken a large meander (LM) path since summer of 2017. During the LM period, the coastal water became warmer in the area from southeast off the Kii Peninsula to south off the bay, possibly due to westward Kuroshio bifurcation. The warming of the coastal waters caused both rise of air temperature and convergence of surface winds in the downstream area of the strengthening northerly winds. The results led us to the conclusion that the linear trends of the surface winds in Suruga Bay are caused by the warming of the coastal waters off the bay, associated with the Kuroshio large meander since summer of 2017.