RELATIVE ANGULAR-MOMENTUM BALANCES OF QUASI-GEOSTROPHIC CIRCULATION MODELS

Calculations of the local vertical component of relative angular momentum are considered for quasi-geostrophic circulation models. The angular momentum diagnostic measures the net horizontal spin of the flow within an ocean basin and complements traditional budgets of energy, vorticity and linear momentum. In particular, the diagnostic can help identify the role of bottom topographic stresses in driving ocean circulation. Calculations of torque balances are presented for several numerical experiments with single-layer and multi-layer models. Experiments with an idealized continental slope topography develop a cyclonic circulation in the abyssal layer which is driven by a significant topographic form torque.