Anthropogenic impact on Agulhas leakage.

Biastoch, Arne and Böning, Claus W. (2013) Anthropogenic impact on Agulhas leakage. Open Access Geophysical Research Letters, 40 (6). pp. 1138-1143. DOI 10.1002/grl.50243.

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Abstract

Recent work suggests that changes of the Southern Hemisphere (SH) winds led to an increase in Agulhas leakage and a corresponding salinification of the Atlantic. Climate model projections for the 21st century predict a progressive southward migration and intensification of the SH westerlies. The potential effects on the ocean circulation of such an anthropogenic trend in wind stress are studied here with a high-resolution ocean model forced by a step-function change in SH wind stress that involves a 7% increase in westerlies strength and a 2° shift in the zero wind stress curl. The model simulation suggests a rapid dynamic adjustment of Agulhas leakage by 4.5 Sv, about a third of its original value, after a few years. The change in leakage is reflected in a concomitant change in the transport of the South Atlantic subtropical gyre, but leads only to a small increase in the Atlantic Meridional Overturning Circulation (AMOC) of O(1 Sv) after three decades. A main effect of the increasing inflow of Indian Ocean waters with potential long-term ramifications for the AMOC is the salinification and densification of upper-thermocline waters in the South Atlantic, which extends into the North Atlantic within the first three decades.

Document Type: Article
Additional Information: WOS:000319215700022
Keywords: Agulhas leakage; Atlantic Meridional Overturning; GENERAL-CIRCULATION MODEL; DECADAL VARIABILITY; GLOBAL CLIMATE; SOUTHERN-OCEAN; ATLANTIC; EXCHANGE; WINDS
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-TM Theory and Modeling
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1002/grl.50243
ISSN: 0094-8276
Projects: BMBF Nordatlantik, KCM
Expeditions/Models/Experiments:
Date Deposited: 02 May 2013 12:37
Last Modified: 18 Feb 2020 09:16
URI: http://oceanrep.geomar.de/id/eprint/21193

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