Directly measured mid-depth circulation in the northeastern North Atlantic Ocean

被引:176
作者
Bower, AS [1 ]
Le Cann, B
Rossby, T
Zenk, W
Gould, J
Speer, K
Richardson, PL
Prater, MD
Zhang, HM
机构
[1] Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA
[2] UFR Sci, CNRS, Lab Phys Oceans, F-29285 Brest, France
[3] Univ Rhode Isl, Grad Sch Oceanog, Kingston, RI 02881 USA
[4] Univ Kiel, Inst Meereskunde, D-24105 Kiel, Germany
[5] Southampton Oceanog Ctr, Southampton SO14 3ZH, Hants, England
[6] Florida State Univ, Dept Oceanog, Tallahassee, FL 32306 USA
基金
美国国家科学基金会;
关键词
D O I
10.1038/nature01078
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
The circulation of water masses in the northeastern North Atlantic Ocean has a strong influence on global climate owing to the northward transport of warm subtropical water to high latitudes(1). But the ocean circulation at depths below the reach of satellite observations is difficult to measure, and only recently have comprehensive, direct observations of whole ocean basins been possible(2-4). Here we present quantitative maps of the absolute velocities at two levels in the northeastern North Atlantic as obtained from acoustically tracked floats. We find that most of the mean flow transported northward by the Gulf Stream system at the thermocline level (about 600 m depth) remains within the subpolar region, and only relatively little enters the Rockall trough or the Nordic seas. Contrary to previous work(5,6), our data indicate that warm, saline water from the Mediterranean Sea reaches the high latitudes through a combination of narrow slope currents and mixing processes. At both depths under investigation, currents cross the Mid-Atlantic Ridge preferentially over deep gaps in the ridge, demonstrating that sea-floor topography can constrain even upper-ocean circulation patterns.
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页码:603 / 607
页数:5
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