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Original Research Papers

On the spontaneous transition to asymmetric thermohaline circulation

Authors:

Johan Nilsson ,

Department of Meteorology, Stockholm University, SE-10691 Stockholm, SE
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Göran Broström,

Department of Meteorology, Stockholm University, SE-10691 Stockholm, SE
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Gösta Walin

Department of Oceanography, Earth Sciences Centre, Göteborg University, Box 460, SE-40530 Göteborg, SE
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Abstract

Observations from the northern shore of the Gulf of Finland show a quasi-stable brackish coastal current flowing along a sloping bottom. Other examples of similar currents have been found, for example, in the Arctic basin. Generally, baroclinic flows of this type tend to be unstable. To study the stability of such flows, a specially designed numerical experiment has been devised. The simulations show that a current structure resembling that found in the observations results from an internal baroclinic adjustment of the flow to a baroclinically quasi-stable state with monotonic isopycnal vorticity.

On the basis of the observations and numerical results, we propose that coastal currents for a certain part of the parameter range have an inherent tendency to evolve towards a quasi-stable state. This baroclinic neutralization is suggested as an explanation of the observed persistence of buoyant coastal currents under favorable conditions.

How to Cite: Nilsson, J., Broström, G. and Walin, G., 2004. On the spontaneous transition to asymmetric thermohaline circulation. Tellus A: Dynamic Meteorology and Oceanography, 56(1), pp.68–78. DOI: http://doi.org/10.3402/tellusa.v56i1.14393
  Published on 01 Jan 2004
 Accepted on 19 Sep 2003            Submitted on 19 May 2003

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