scholarly journals Indo‐Atlantic Exchange, Mesoscale Dynamics, and Antarctic Intermediate Water

2018 ◽  
Vol 123 (5) ◽  
pp. 3286-3306 ◽  
Author(s):  
Tonia Astrid Capuano ◽  
Sabrina Speich ◽  
Xavier Carton ◽  
Remi Laxenaire
Keyword(s):  
Intermediate Water ◽  
Antarctic Intermediate Water ◽  
Mesoscale Dynamics

Nonlinear Climate Responses to Changes in Antarctic Intermediate Water

2013 ◽  
Vol 26 (22) ◽  
pp. 9175-9193 ◽  
Author(s):  
Jennifer A. Graham ◽  
David P. Stevens ◽  
Karen J. Heywood
Keyword(s):  
Climate Model ◽  
Potential Temperature ◽  
Heat Fluxes ◽  
Meridional Overturning Circulation ◽  
Intermediate Water ◽  
Antarctic Intermediate Water ◽  
Surface Ocean ◽  
The North ◽  
Meridional Overturning ◽  
Circumpolar Current

Abstract The global impact of changes in Antarctic Intermediate Water (AAIW) properties is demonstrated using idealized perturbation experiments in a coupled climate model. Properties of AAIW were altered between 10° and 20°S in the Atlantic, Pacific, and Indian Oceans separately. Potential temperature was changed by ±1°C, along with density-compensating changes in salinity. For each of the experiments, sea surface temperature responds to changes in AAIW when anomalies surface at higher latitudes (>30°). Anomalous sea-to-air heat fluxes leave density anomalies in the ocean, resulting in nonlinear responses to opposite-sign perturbations. In the Southern Ocean, these affect the meridional density gradient, leading to changes in Antarctic Circumpolar Current transport. The response to cooler, fresher AAIW is both greater in magnitude and significant over a larger area than that for warmer, saltier AAIW. The North Atlantic is particularly sensitive to cool, fresh perturbations, with density anomalies causing reductions in the meridional overturning circulation of up to 1 Sv (1 Sv ≡ 106 m3 s−1). Resultant changes in meridional ocean heat transport, along with surfacing anomalies, cause basinwide changes in the surface ocean and overlying atmosphere on multidecadal time scales.

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