In this project, the P.I.'s will continue development and application of intermediate models of the gyre-scale ocean circulation based on the balance equations (BE). BE contains more dynamics than the quasi-geostrophic (QG) models, but requires substantially less computer capacity than the primitive equation (PE) models. Wind and thermal forcing are both included. Successful adiabatic models will be extended to include diabatic effects of buoyancy and wind forcing, and related sub-grid-scale mixing algorithms.