Circulation Characteristics in Three Eddy-Permitting Models of the North Atlantic

• Published in: Progress in Oceanography
• Main Authors: Willebrand, Jürgen, Barnier, B., Böning, Claus W., Dieterich, Christian, Killworth, P., LeProvost, C., Yia, J., Molines, J.-M., New, A.L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2001
• Subjects: Greenland; North Atlantic
• Online Access: https://oceanrep.geomar.de/id/eprint/3215/; https://oceanrep.geomar.de/id/eprint/3215/1/Willebrand.pdf; https://doi.org/10.1016/S0079-6611(01)00003-9

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