Antarctic Slope Current: System, Classification and Annual Variability Models


The Antarctic Slope Current (ASC) circumnavigates the Antarctic continent following the continental slope, separating the waters on the continental shelf from the deeper offshore Southern Ocean and regulates the flow towards the Antarctic coastline. We can classify the current’s frontal structure in 3 ranges: warm shelf, fresh shelf and dense shelf. It is difficult to reveal its spatial and sub-annual variability, as direct velocity measurements are sparse. Spatial variability of the ASC has also been characterized as three flow regimes: the surface-intensified ASC, the bottom-intensified ASC, and the reversed ASC. The surface-intensified ASC regime is stronger in the winter months. Seasonality of the winds may be the relevant driver for the seasonality along stretches of the coastline with a surface-intensified ASC. The reversed ASC has an inverted seasonality, meaning it is weaker in the winter months. The surface-intensified ASC occurs at sections of the continental slope with a fresh shelf, the bottom-intensified ASC occurs at dense shelves, and the reversed ASC occurs at warm shelves. Seasonality of the ASC is influenced not only by the mechanical forcing provided by the winds and sea ice at the ocean surface, but also by a geostrophic adjustment to changes in the cross-slope density gradient via freshwater input from basal melting and via surface water mass transformation.

Poster number:



Rosalina Ribeiro

GEOF338 - Spring 2024

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