Direct and remote effects of topography and orientation, and the dynamics of mesoscale eddies

Baroclinic instability in the ocean is a primary cause of mesoscale eddies, which are pockets of water in the scale of 100km that have different density, thermal, and rotational characteristics than their surroundings. First observed in the early 1900s, eddies are thought to be a predominant reason for the heat flux between the equator and the poles in both the ocean and the atmosphere. In attempt to understand this process better, this study uses a series of numerical simulations performed on high performance computing systems. The calculations are based on the Massachusetts Institute of Technology general circulation model, which is used to compare lateral heat transport between different simulations. The specific objectives of this project include i) Comparison the direct and remote interactions of shear with topographic slope. The direct scenario is one in which the shear extends throughout the entire ocean depth and is therefore in direct contact with the sea floor, whereas in the remote scenario there is a spatial separation between the shear in the upper half of the basin and the bottom topography, ii) Analysis of the system response to changes in the zonal and meridional seafloor slope and iii), Investigation of the effect of orientation changes in the mean large-scale current on cross-flow fluxes. The lateral heat transport and diffusivity of these simulations are then compared to our analytic model, known as Growth Rate Balance, which is based on the balance between growth rate (primary) instabilities deduced from linear theory and numerically generated secondary instabilities.http://archive.org/details/directndremoteef1094556130Lieutenant Commander, United States NavyApproved for public release; distribution is unlimited