TRANSPORTS AND BUDGETS OF VOLUME, HEAT, AND SALT FROM A GLOBAL EDDY-RESOLVING OCEAN MODEL

The results from an integration of a global ocean circulation model ha ve been condensed into an analysis of the volume, heat, and salt trans ports among the major ocean basins. Transports are also broken down be tween the model's Ekman, thermocline, and deep layers. Overall, the mo del does well. Horizontal exchanges of mass, heat, and salt between oc ean basins have reasonable values; and the volume of North Atlantic De ep Water (NADW) transport is in general agreement with what limited ob servations exist. On a global basis the zonally integrated meridional heat transport is poleward at all latitudes except for the latitude ba nd 30-degrees-S to 45-degrees-S. This anomalous transport is most like ly a signature of the model's inability to form Antarctic Intermediate (AAIW) and Antarctic bottom water (AABW) properly. Eddy heat transpor t is strong at the equator where its convergence heats the equatorial Pacific about twice as much as it heats the equatorial Atlantic. The g reater heating in the Pacific suggests that mesoscale eddies may be a vital mechanism for warming and maintaining an upwelling portion of th e global conveyor-belt circulation. The model's fresh water transport compares well with observations. However, in the Atlantic there is an excessive southward transport of fresh water due to the absence of the Mediterranean outflow and weak northward flow of AAIW. Eddies in the mid-latitudes act to redistribute heat and salt down the mean gradient s. Residual fluxes calculated from a sum of the computed advective (in cluding eddies), forced, and stored fluxes of heat and salt represent transport mostly due to vertical sub-grid scale mixing processes. Perh aps the model's greatest weakness is the lack of strong AAIW and AABW circulation cells. Accurate thermohaline forcing in the North Atlantic (based on numerous hydrographic observations) helps the model adequat ely produce NADW. In contrast, the southern ocean is an area of sparse observation. Better thermohaline observations in this area may be nee ded if models such as this are to produce the deep convection that wil l achieve more accurate simulations of the global 3-dimensional circul ation.