Letter. Slowing of the Atlantic meridional overturning circulation at 25° N


Bryden, H.L., Longworth, H.R. and Cunningham, S.A. (2005) Letter. Slowing of the Atlantic meridional overturning circulation at 25° N. Nature, 438, (7068), 655-657. (doi:10.1038/nature04385).

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Original Publication URL: http://dx.doi.org/10.1038/nature04385

Description/Abstract

The Atlantic meridional overturning circulation carries warm upper waters into far-northern latitudes and returns cold deep waters southward across the Equator. Its heat transport makes a substantial contribution to the moderate climate of maritime and continental Europe, and any slowdown in the overturning circulation would have profound implications for climate change. A transatlantic section along latitude 25° N has been used as a baseline for estimating the overturning circulation and associated heat transport. Here we analyse a new 25° N transatlantic section and compare it with four previous sections taken over the past five decades. The comparison suggests that the Atlantic meridional overturning circulation has slowed by about 30 per cent between 1957 and 2004. Whereas the northward transport in the Gulf Stream across 25° N has remained nearly constant, the slowing is evident both in a 50 per cent larger southward-moving mid-ocean recirculation of thermocline waters, and also in a 50 per cent decrease in the southward transport of lower North Atlantic Deep Water between 3,000 and 5,000 m in depth. In 2004, more of the northward Gulf Stream flow was recirculating back southward in the thermocline within the subtropical gyre, and less was returning southward at depth.

Item Type: Article
ISSNs: 0028-0836 (print)
Related URLs:
Keywords: gulf stream, ocean circulation, north atlantic current, climatic changes
Subjects: G Geography. Anthropology. Recreation > GC Oceanography
Divisions: University Structure - Pre August 2011 > School of Ocean & Earth Science (SOC/SOES)
University Structure - Pre August 2011 > National Oceanography Centre (NERC)
ePrint ID: 19134
Date Deposited: 03 Jan 2006
Last Modified: 27 Mar 2014 18:08
URI: http://eprints.soton.ac.uk/id/eprint/19134

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