A review of numerical ocean modeling (1983–1986): Midlatitude mesoscale and gyre‐scale

Abstract

For the years 1983 to the present, numerical modeling of midlatitude ocean circulation on the mesoscale and gyre‐scale is reviewed. Numerical results have shown great similarity to recent thermocline theories, but also some important differences. In particular, ventilation of the “pool zone”, caused by convective processes, is substantial; also, solutions employing explicitly‐resolved eddies differ significantly from their equilibrium counterparts. Inverse methods have provided improved estimates of meridional heat transport and tropical upwelling of tracers. The crucial influence of the western boundary on the circulation of the gyre interior is beginning to be understood. Research has focused on the conditions for radiation by jets, the relationship between a jet's structure and its stability, and the generation of deep mean flows by eddy activity near the surface. Constraints on the structure of isolated vortices imposed by instability mechanisms have been explored with new balanced models, which provide an inexpensive but accurate alternative to primitive equation models for many oceanic processes. Transport of salinity by Gulf Stream rings has been found to be comparable to the effects of evaporation and precipitation in the Slope Water. It has also been shown that radial circulation in warm‐core rings cannot be disregarded as a possible cause of ring spin‐down. In anticipation of a dramatic increase in the oceanic observational data base from altimetry, scatterometry, tomography, and in situ measurement, new modeling techniques for data assimilation and prediction are beginning to be developed.