Circulation characteristics in three eddy-permitting models of the North Atlantic

• Main Authors: Willebrand, J., Barnier, B., Böning, Carmen, Dieterich, C., Killworth, P. D., Le Provost, C., Jia, Y., Molines, J.-M., New, A. L.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2001
• Subjects: Greenland; North Atlantic
• Online Access: https://epic.awi.de/id/eprint/5009/; https://epic.awi.de/id/eprint/5009/1/Wil2001b.pdf; https://hdl.handle.net/10013/epic.15577; https://hdl.handle.net/10013/epic.15577.d001

A systematic intercomparison of three realistic eddy-permitting models of the North Atlanticcirculation has been performed. The models use different concepts for the discretization of thevertical coordinate, namely geopotential levels, isopycnal layers, terrain-following (sigma)coordinates, respectively. Although these models were integrated under nearly identicalconditions, the resulting large-scale model circulations show substantial differences. The resultsdemonstrate that the large-scale thermohaline circulation is very sensitive to the modelrepresentation of certain localised processes, in particular to the amount and water massproperties of the overflow across the Greenland-Scotland region, to the amount of mixing withina few hundred kilometers south of the sills, and to several other processes at small or sub-gridscales. The different behaviour of the three models can to a large extent be explained as aconsequence of the different model representation of these processes.