Using ocean margin density to constrain ocean circulation and surface wind strength in the past

The density structure along the ocean margins carries an integrated imprint of ocean circulation. The difference in pressure between the eastern and western margins of the ocean reflects the net meridional geostrophic transport across the ocean basin. If one assumes that the wind driven circulation is closed in the upper ocean, the wind driven component of the net geostrophic transport is equal in magnitude and opposite in direction to the Ekman transport. The remainder of the net meridional geostrophic transport is the upper branch of the thermohaline meridional overturning circulation. The meridional geostrophic transports calculated using the ocean margin density data collected during World Ocean Circulation Experiment (WOCE) reflect both the wind driven and thermohaline overturning circulations. Density along the ocean margins for times in the past can be estimated from the oxygen isotopic composition of benthic foraminifera. These ocean margin density estimates can then be used to help constrain the shear in the meridional overturning circulation, the strength of zonal surface winds over the oceans, and the resulting wind driven circulation. These data will also provide an important complement to existing paleoceanographic reconstructions of surface conditions and deep water tracer fields which are currently used to constrain models of past ocean circulation.