On the modified Circumpolar Deep Water upwelling over the Four Ladies Bank in Prydz Bay, East Antarctica.

Analyses of hydrographic observation data sets revealed that modified Circumpolar DeepWater (mCDW) tends to flood the western flank (73˚ E-78˚ E, 67˚ S-68˚ S) of the FourLadies Bank (FLB) in Prydz Bay. In this study, we investigated the mechanism responsiblefor mCDW upwelling over the FLB based on an eddy-resolving coupled ocean-sea ice-iceshelf model in conjunction with the latest high-accuracy bathymetry. It was found that zonalstep-like declines in the seabed over the FLB are crucial for the mCDW onshore upwelling,through topographic dynamic effects on the alongshore Antarctic Slope Current (ASC).In the presence of meridional cross-shelf σθ isopycnals, warm mCDW at ∼500m depth in the deep sea can make its approach to the shallower continental shelf(∼200-500 m depths), characterized as a warm layer (> -1.8 ˚ C) bounded by thecross-shelf σθ isopycnal surfaces of 27.5 kg m-3 and 27.7 kg m-3. The simulated outflowof the Prydz Bay gyre is concentrated to the eastern flank of the Prydz Channel.These results suggest that, in addition to the depressions and troughs around theAntarctic, smaller topographic features such as step-like declines in the seabed near theASC are also favorable for onshore mCDW intrusion. This study demonstrates thatmCDW onshore transport around the Antarctic continental shelf might be significantlyunderestimated by numerical models with coarse spatial representations of the topography. [ABSTRACT FROM AUTHOR]