01/11/2010
Current Ocean Model Approximation Uncertain in Polar Regions
Summary
Ocean general circulation models (OGCMs) treat the ocean as a thin, rotating fluid, where motions are predominantly horizontal with limited vertical velocities and accelerations. Although these approximate equations have been successful in modeling ocean circulation there are phenomena, such as deep convection and flow instabilities that play a role in the large-scale circulation. Scientists at Los Alamos National Laboratory have shown that key approximations made in OGCMs favor eddy producing instabilities in some regimes over other types of instabilities, suppress growth rates for some instabilities, and create symmetry in internal wave production. This work implies that errors due to these approximations are most predominant in the Polar Regions and suggests new directions for modeling Deep Ocean mixing.
References
Jeffery, N., and B. Wingate, 2009: The Effect of Tilted Rotation on Shear Instabilities at Low Stratifications. J. Phys. Oceanogr., 39, 3147-3161.