Numerical models of the ocean circulation

Numerical models of the large‐scale circulation of the oceans have developed into a useful tool for the interpretation of oceanographic data and the planning of new observational programs. Idealized numerical models with simplified geometry and physics have extended the analytic theory of the wind‐driven ocean circulation into the range in which inertial effects determine the solution. Recent numerical work has shown how stratification and baroclinic instability further modify a wind‐driven ocean circulation. Other results obtained by simplified numerical models include important predictions about the spectral properties of geostrophic turbulence in the ocean. Another class of numerical models has been developed which attempts to model the geometry and physics of the ocean circulation in a more detailed way, allowing a quantitative comparison with observations. Interesting results have been obtained for the Indian Ocean which simulate the seasonal variations of the Somali Current. Other Soviet and U.S. model studies using the observed density field as input show that pressure torques acting on bottom topography can be as large as the torques exerted by the wind acting at the surface. As yet, detailed simulations of the ocean circulation in a major ocean basin which include the effect of mesoscale eddies have not been undertaken.