| Exchange of warm, nutrient-rich Circumpolar Deep Water (CDW) onto Antarcticcontinental shelves and coastal seas has important effects on physical andbiological processes. This water mass moderates the ice cover through heatflux, provides a relatively warm subsurface environment for some animals andprovides nutrients to stimulate primary production. CDW exchange is knownto be episodic, but persistent, and is thought to occur at specificlocations due to bottom topography. The present study investigates thelocations of this exchange and their dynamics in the Ross Sea and westAntarctic Peninsula with a high resolution three dimensional numericalmodel.Calculations of the advective transport across the shelf break and budgetson the shelf of heat, salt and nutrients show that the cross shelf breaktransport of CDW is very important to the total budgets on both shelves.There is a significant correlation between the curvature of the shelf breakand the transport across the shelf break. A momentum term balance showsthat momentum advection helps to force flow across the shelf break inspecific locations due to the curvature of the bathymetry (that is, theisobaths curve in front of the flow). For the model to create a strongintrusion of CDW onto the shelf, it appears two mechanisms are necessary.First, CDW is driven onto the shelf at least partially due to momentumadvection and the curvature of the shelf break; then, the generalcirculation on the shelf takes the CDW into the interior. |
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