THE SEA-SURFACE PRESSURE FORMULATION OF RIGID LID MODELS - IMPLICATIONS FOR ALTIMETRIC DATA ASSIMILATION STUDIES

The sea surface pressure formulation of the rigid lid primitive equati on oceanic problem is reviewed and clarified. The geostrophic limit fo r the sea surface pressure equation is then considered and a new diagn ostic relationship is found that relates the surface pressure to the b arotropic and baroclinic components of the subsurface flow field. We d emonstrate that a direct insertion in the model equations of sea surfa ce information, such as that provided by satellite altimetry, does not produce changes in the subsurface dynamics due to the divergenceless nature of the barotropic flow field. The geostrophic limit of the sea surface pressure field computed from a standard general circulation mo del of the world ocean is presented and the barotropic/baroclinic comp onents of the absolute dynamic topography of the global general circul ation are discussed.