Model Setup
The model code used is the Massachusetts Institute of Technology general circulation model (MITgcm) (Marshall 1997). The MITgcm is a finite volume primitive equation model solving the incompressible Navier-Stokes equations. The MITgcm can be downloaded here.
The southern ocean has complex non-linear dynamics which require A simple box ocean can then be used to run a high-resolution simulation to enable us to examine the basic physics controlling Southern Ocean diabatic eddies.
Higher resolution both increases the number of grid points and requires shorter time steps to satisfy the CFL condition (discussed separately later) therefore increases in resolution rapidly increasing computational cost. For the purpose of investigating eddy dynamics the coarsest resolution that is acceptable will be ``just about" eddy resolving. The Rossby radius of deformation () is calculated by:
where N is the buoyancy frequency typically , H is thickness scale (typically 1000 m) and f is the Coriolis parameter (
). Using those typical values we can estimate the Rossby radius 10-30 km. To resolve for eddies a minimum of 2 grid spacing per radius is required, therefore we can use 5km as our horizontal resolution.
Gendata.py is an example python script generating the model grid and forcing for ease of reading I have included an ipython notebook with the figures and equations in Gendata.ipynb