Along-Stream Evolution of Gulf Stream Volume Transport
Along-Stream Evolution of Gulf Stream Volume Transport
复制标题
DOI：
10.1175/jpo-d-19-0303.1
复制
发表时间：
2020-08-01
影响因子：
3.5
通讯作者：
Todd, Robert E.
中科院分区：
文献类型：
--
作者：
Heiderich, Joleen;Todd, Robert E.
墨西哥湾流通过向极地输送水和热量影响全球气候。海流的流量在美国东海岸沿着显著增加。利用自主水下滑翔机的广泛观测方案提供了沿墨西哥湾流路径跨越沿着158多个纬度的水文和流速的精细尺度地下观测，从而填补了佛罗里达海峡和哈特拉斯角下游长期运输测量之间1 500公里长的空白。在这里，滑翔机的观察与船上的测量沿沿着W 68度W附近提供了一个详细的图片，沿流运输的增加。为了解释墨西哥湾流曲率和邻近环流的影响（例如，共转涡）的运输估计，上，下边界运输构造为每个跨墨西哥湾流样带。1000米以上时均输运量的上限估计值为：佛罗里达海峡为32.9 +/- 1.2 Sv（1 Sv相当于106 m（3）s（-1）），哈特拉斯角为57.3 +/- 1.9 Sv，W线为75.6 +/- 4.7 Sv。相应的下限估计值在佛罗里达海峡为32.3 +/- 1.1 Sv，在哈特拉斯角为54.5 +/- 1.7 Sv，在W线为69.9 +/- 4.2 Sv。利用滑翔机和W线的温盐观测资料，将沃茨分为7类，研究了墨西哥湾流输送和夹带的沃茨的性质。在1000米以上的墨西哥湾流总流量的增加，大部分源于亚温跃层沃茨的夹带，包括上拉布拉多海水和十八度水。
The Gulf Stream affects global climate by transporting water and heat poleward. The current's volume transport increases markedly along the U.S. East Coast. An extensive observing program using autonomous underwater gliders provides finescale, subsurface observations of hydrography and velocity spanning more than 158 of latitude along the path of the Gulf Stream, thereby filling a 1500-km-long gap between long-term transport measurements in the Florida Strait and downstream of Cape Hatteras. Here, the glider-based observations are combined with shipboard measurements along Line W near 68 degrees W to provide a detailed picture of the along-stream transport increase. To account for the influences of Gulf Stream curvature and adjacent circulation (e.g., corotating eddies) on transport estimates, upper-and lower-bound transports are constructed for each cross-Gulf Stream transect. The upper-bound estimate for time-averaged volume transport above 1000m is 32.9 +/- 1.2 Sv (1 Sv equivalent to 106 m(3) s(-1)) in the Florida Strait, 57.3 +/- 1.9 Sv at Cape Hatteras, and 75.6 +/- 4.7 Sv at Line W. Corresponding lower-bound estimates are 32.3 +/- 1.1 Sv in the Florida Strait, 54.5 +/- 1.7 Sv at Cape Hatteras, and 69.9 +/- 4.2 Sv at Line W. Using the temperature and salinity observations from gliders and Line W, waters are divided into seven classes to investigate the properties of waters that are transported by and entrained into the Gulf Stream. Most of the increase in overall Gulf Stream volume transport above 1000m stems from the entrainment of subthermocline waters, including upper Labrador Sea Water and Eighteen Degree Water.