Abstract

Oceanic transport across the Antarctic continental slope has a pivotal control on both the global meridional overturning circulation and, via land-ice melt, global sea level. Observations of ocean transport across the Antarctic continental slope are relatively scarce, dominated by summer measurements and are focused in particular regions of interest, such as the west Antarctic Peninsula. Numerical modelling of the circulation around the Antarctic margins is also difficult, due to the high resolution required to simulate overflows and a mesoscale field with a typical Rossby radius of less than 5 km. As a result, we know very little about what controls the cross-slope transports and if and how the transports of the different water masses are dynamically related to one another. Here, we use a global, eddying ocean-sea ice model to quantify the spatial distribution of cross-slope Circumpolar Deep Water transport around Antarctica, to look at the influence of variations in wind stress forcing on the exchange and to explore the connection between overflowing Dense Shelf Water (DSW) and onshore transport of Circumpolar Deep Water (CDW). We show results from both a circumpolar analysis, and a local regional analysis in the Ross Sea, to infer that DSW export places a major constraint on the location and magnitude of onshore CDW transport.