Slope/Shelf Circulation and Cross-Slope/Shelf Transport Out of a Bay Driven by Eddies from the Open Ocean

摘要

Interaction between the Antarctic Circumpolar Current and the continental slope/shelf in the Marguerite Bay and west Antarctic Peninsula is examined as interaction between a wind-driven channel flow and a zonally uniform slope with a bay-shaped shelf to the south. Two control mechanisms, eddy advection and propagation of topographic waves, are found important for eddy topography interactions. The topographic waves become more nonlinear near the western (eastern if in the Northern Hemisphere) boundary of the bay, inducing strong cross-escarpment motions. A two-layer wind-driven channel flow spontaneously generates eddies through baroclinic instability. A PV front forms in the first layer shoreward of the base of the topography due to the lower- layer eddy-slope interactions. Both the cross-slope-edge transport and the out- of-bay transport are comparable with the model Ekman transport, suggesting the significance of the examined mechanism. The wave-boundary interaction is essential for the out-of-bay transport. Much more water is transported out of the bay from the west, and the southeastern area is the most isolated region. These results suggest that the southeastern region of the Marguerite Bay is a retention area for Antarctic krill.