Multiple Equilibria in a Global Ocean General Circulation Model

• Main Authors: Power, S. B., Kleeman, R.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 1993
• Subjects: GCM; global ocean; heat flux; multiple equilibria; Pacific; North Atlantic Deep Water; North Atlantic
• Online Access: https://research.usq.edu.au/item/q6x02/multiple-equilibria-in-a-global-ocean-general-circulation-model; https://doi.org/10.1175/1520-0485(1993)023<1670:MEIAGO>2.0.CO;2

A global ocean general circulation model is forced using various upper boundary conditions (BCs) on temperature and salinity. Solutions are obtained under restoring and mixed BCs (i.e., a restoring condition on the upper-level temperature but using a fixed, specified surface salt flux). Salt flux anomalies are temporarily applied under mixed BCs, and solutions are obtained in which overturning associated with deep-water formation is either present or absent in the North Atlantic and either vigorous or weak in the North Pacific. A comparison between these solutions helps to clarify the role North Atlantic deep-water formation plays in maintaining the current climate. The surface heat fluxes differ substantially between the solutions, and their very existence is dependent upon these differences. As a result they are not multiple equilibra of the ocean model alone. Instead, they should be regarded as multiple equilibria of a very crude coupled atmosphere-ocean system.