Abstract Hurricane Dorian (28-August to 6-September 2019) was one of the most powerful hurricanes ever recorded in the Atlantic Ocean; it had disastrous impact on the Bahamas, before moving along the southeastern coast of the U.S. The unusual track of Dorian followed the track of hurricane Matthew (2016)- both hurricanes moved along the Gulf Stream (GS) without making a significant landfall and both seemed to weaken the flow of the GS by almost 50%. In the case of Dorian, the transport of the Florida Current (FC) measured by the cable across the Florida Straits had dropped from 34.7 Sv (1 Sv = 106 m3/s) on 22-August before the storm, to 17.1 Sv on 4-September (the lowest recorded value since measurements started in 1982). Two questions that this study tried to answer are: 1. Did the disruption that Dorian caused to ocean currents off the Florida coast affect the large-scale Gulf Stream (GS) dynamics downstream? and 2. Was there a long-term impact on the GS flow and on coastal sea level? Satellite altimeter data showed that the signal of the hurricane's impact on reducing the GS flow near the Florida coast is seen as far as 4000 km downstream along the GS path 50 days later. This long period of a weakened GS flow can elevate coastal sea level and increase flooding in the days and weeks after offshore storms already disappeared. The observed FC transport was found to be significantly correlated with the downstream GS velocity as far as 50°W and was anti-correlated with sea level along the entire U.S. East Coast. The density and velocity anomaly created by the hurricane's cooling and mixing near the Florida coast seemed to propagate downstream with the GS flow at ~1 m/s, but slow-moving baroclinic waves with propagation speed of ~0.1 m/s were also observed along the GS path. The results of this study may have implications for the indirect impact of storms on large-scale ocean circulation, coastal processes and the response of coastal ecosystems to offshore changes.

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飓风多里安 (2019) 对墨西哥湾流和海岸的长期和深远影响

摘要 飓风多里安（2019 年 8 月 28 日至 9 月 6 日）是大西洋有史以来最强的飓风之一；在沿着美国东南海岸移动之前，它对巴哈马造成了灾难性的影响 多利安不寻常的轨迹跟随飓风马修（2016 年）的轨迹——两场飓风都沿着墨西哥湾流（GS）移动，但都没有明显登陆将 GS 的流量减弱近 50%。在多里安的情况下，通过佛罗里达海峡的电缆测量的佛罗里达洋流 (FC) 的传输从风暴前 22 日至 8 月的 34.7 Sv (1 Sv = 106 m3/s) 下降到 4 月的 17.1 Sv - 9 月（自 1982 年开始测量以来的最低记录值）。本研究试图回答的两个问题是：1。多里安对佛罗里达海岸外洋流造成的破坏是否影响了下游的大规模墨西哥湾流 (GS) 动态？和 2. 对 GS 流量和沿海海平面是否有长期影响？卫星高度计数据显示，飓风对减少佛罗里达海岸附近 GS 流量的影响信号在 50 天后沿着 GS 路径向下游 4000 公里处可见。在离岸风暴已经消失后的数天和数周内，长时间减弱的 GS 流会升高沿海海平面并增加洪水。发现观察到的 FC 传输与下游 GS 速度显着相关，最远可达 50°W，并且与整个美国东海岸的海平面反相关。飓风造成的密度和速度异常' 佛罗里达海岸附近的 s 冷却和混合似乎随着 GS 流向下游传播，速度约为 1 m/s，但沿 GS 路径还观察到传播速度为 0.1 m/s 的缓慢移动的斜压波。这项研究的结果可能对风暴对大规模海洋环流、沿海过程和沿海生态系统对近海变化的响应的间接影响产生影响。