| Summary: | The exchange of water masses between the shallow Weddell Sea continental shelf and the deep ocean is of climatic importance. Firstly, on-shelf transport of warm oceanic water masses, contributes to basal melting of ice shelves, which affects the stability of the Antarctic Ice Sheet. Secondly, export of denseWeddell Sea shelf water, contributes to production of Antarctic Bottom Water (AABW), which feeds into the lower limb of the global thermohaline circulation. This thesis considers processes related to both on-shelf heat transport, and to export of dense shelf water. Based on a combination of idealized numerical model experiments and observations of hydrography and current at various locations in the southern Weddell Sea, the thesis discusses pathways and variability of the oceanic circulation along the continental slope, on the continental shelf and inside the Filchner Trough (FT), a deep trough across the continental shelf. The response to wind forcing is assessed, along with mechanisms contributing to mixing and transformation of water masses. The Antarctic Slope Front (ASF) protects the Weddell Sea continental shelf from the salineWarm DeepWater (WDW) offshore. Most of the on-shore transport occurs in the summer season, when the thermocline is shoaling at the shelf break, and through the FT, where the sill depth is 200 m below the shelf depth. However, on-shelf transport of warm water may also occur when dense shelf water is present on the shelf. An isopycnal connection between the dense shelf water and the WDW offshore creates a pathway for WDWto access the shelf without doing work against the buoyancy forces. The southward transport of heat into the FT is sensitive to the slope current properties, and to the characteristics of the dense shelf water. The slope current is associated with the ASF, and flows westward along the continental slope. The core of the slope current is found to migrate shoreward onto shallower isobaths under strong wind forcing, leading to different inflow regimes in the FT. In the ...
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