The Southern Ocean : a possible source region for tropical Atlantic variability?
Date
2003
Authors
Hickey, Hannah
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Abstract
A coupled model of intermediate complexity is used to examine the effect of Southern Ocean salinity, temperature and wind anomalies on tropical Atlantic variability. We find that positive freshwater, temperature and wind anomalies in the Southern Ocean all cause increased advection into the Atlantic basin, resulting in anomalously cold and fresh water in the eastern Atlantic Ocean at 25°S. Over time, this anomaly spreads northwards and away from the coast, into the tropics. The magnitude of the response increases linearly with the strength of the forcing. The results of these experiments show that southeastern Atlantic Ocean temperature and salinity are particularly sensitive to changes in the Southern Ocean. Limited observational data support the model results. Our findings suggest that this link could be the oceanic branch of a mode of variability linking the Southern and tropical Atlantic Oceans a possible mechanism for the as-yet-unexplained decadal mode of tropical Atlantic variability.