Using an unmanned sailing vehicle, known as a Saildrone, we observed mesoscale and smaller scale structures of oceanic and atmospheric variables across the Kuroshio south of Japan during the winter of 2018/2019. From December 28 to December 29, 2018, the Saildrone crossed just north of the center of a very warm (∼23^∘C) mesoscale spot in the Kuroshio centered around 31.5^∘ N, 135.8^∘ E. The northerly winter monsoon wind was intensified by ∼2 m s⁻¹ over the mesoscale warm spot (MWS) and accompanied by a submesoscale sea level pressure undulation of ∼1 hPa possibly due to two oppositely rotating ageostrophic vortices. At this time, the wind reached a maximum speed of greater than 12 m s⁻¹ and removed heat from the ocean at a rate of 1141 W m⁻². Subsequently (January 3–5, 2019), the Saildrone observed weakening of wind and heat release to the atmosphere on the southern edge of the MWS, which was associated with the approaching low-pressure system over the Kuroshio. The observed submesoscale structures of atmospheric and oceanic variables near the center of the MWS suggest that the atmospheric boundary layer responded to the MWS through the pressure adjustment mechanism in the Kuroshio, where in situ high-resolution measurements have not been performed before.

中文翻译：

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Saildrone观测到的大气边界层对日本南部黑潮沿岸冬季中尺度热点的响应

我们使用一种名为Saildrone的无人驾驶航行器，在2018/2019年冬季观察了日本南部黑潮的中尺度和较小尺度的海洋和大气变量结构。从12月28日到2018年12月29日，该Saildrone越过北部一个非常温暖的中心的（〜2 3 ^∘ C）中尺度黑潮斑点围绕着3 1 。5 ^∘ N，1 3 5 。8 ^∘ E.偏北冬季风风通过加强〜2 米 小号^{- 1}可能是由于两个反向旋转的变质涡，在中尺度的暖区（MWS）上出现的，并伴有约1 hPa的亚中尺度海平面压力波动。此时，风力达到大于最大速度1 2 米 小号^{- 1}的速率和移除热量从海洋1 1 4 1 w ^ 米^{- 2}。随后（2019年1月3日至5日），Saildrone观测到MWS南缘向大气的风和热释放减弱，这与黑潮上空的低压系统有关。在MWS中心附近观测到的大气和海洋变量的亚中尺度结构表明，大气边界层通过黑潮的压力调节机制对MWS做出了响应，而黑潮以前从未进行过原位高分辨率测量。