GISS Dynamic ocean model

This model is a fully dynamic, non-Boussinesq, mass-conserving free surface ocean model (Russell et al, 1995, 2000, Liu et al 2002, 2003). The dynamics is based on a modified Arakawa scheme on the C-grid, with a linear upstream scheme for advecting tracers. Vertical mixing uses the KPP scheme of Large et al (1996). Momentum mixing is modelled as a spatically varying laplacian as in Wajsowicz (1993). The effects of mesoscale eddies and isopycnal diffusion are parameterised as in Gent and McWilliams (1996), but using variable coefficients (Visbeck et al, 1997), and coded as in Griffies (1998).

The model contains up to 12 variable depth subgrid scale straits which contect ocean grid boxes, which would not be connected at the resolution used. In particular, the Straits of Gibraltar, Hormuz, and Nares straits are so modelled. All ocean components are fluxed through these straits as a function of the end to end pressure gradients, balanced against a drag proportional to the straits 'width' which serves as a tuning parameter to get reasonable fluxes.