© 2015 American Meteorological Society. The west-to-east crossover of boundary currents has been seen in mean circulation schemes from several past models of the Red Sea. This study investigates the mechanisms that produce and control the crossover in an idealized, eddy-resolving numerical model of the Red Sea. The authors also review the observational evidence and derive an analytical estimate for the crossover latitude. The surface buoyancy loss increases northward in the idealized model, and the resultant mean circulation consists of an anticyclonic gyre in the south and a cyclonic gyre in the north. In the midbasin, the northward surface flow crosses from the western boundary to the eastern boundary. Numerical experiments with different parameters indicate that the crossover latitude of the boundary currents changes with f0, β, and the meridional gradient of surface buoyancy forcing. In the analytical estimate, which is based on quasigeostrophic, β-plane dynamics, the crossover is predicted to lie at the latitude where the net potential vorticity advection (including an eddy component) is zero. Various terms in the potential vorticity budget can be estimated using a buoyancy budget, a thermal wind balance, and a parameterization of baroclinic instability.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): USA 00002, KSA 00011, KSA 00011/02
Acknowledgements: We have benefited from talkingwith Tom Farrar, Jiayan Yang, Paola Rizzoli, and MikeSpall. This work is supported by Award USA 00002,KSA 00011, and KSA 00011/02 made by King AbdullahUniversity of Science and Technology (KAUST), byNational Science Foundation Grants OCE0927017,OCE1154641, and OCE85464100, and by the Woods HoleOceanographic Institution Academic Program Office.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.