Antarctic Bottom Water, Polynyas, and the Antarctic Circumpolar Wave in High-Resolution Coupled GCMs

Naval Postgraduate School, Monterey CA

Investigators

Abstract

9980607 Zhang This investigation concerns the numerical modeling of the temporal variation of antarctic coastal polynyas and the rate of antarctic bottom water formation. High resolution global models allow the inclusion of coastal polynyas - areas of open water that persist through the winter - and at the same time allow their impact to spread through the world ocean, giving a proper representation of the effect of polynyas on deep ocean ventilation. The research will be focused on the interannual variability of antarctic coastal polynyas, the ice-ocean interactions that are associated with the formation of offshore polynyas, and the modulating effect of the antarctic circumpolar wave. The analysis will concentrate on the output of three high-resolution global models: a twenty-year integration of a coupled ice-ocean model developed by the principal investigators at the Naval Postgraduate School; a three hundred year integration of the National Center for Atmospheric Research Parallel Climate Model, and multi-decadal sensitivity integrations of a coupled ice-ocean model developed at the Los Alamos National Laboratory. The physical insights about the mechanisms of offshore polynya formation are particularly important to understanding the possible influences of climatic change on open ocean deep convection and bottom-water production. Studying the antarctic circumpolar wave will improve our knowledge of air-sea-ice interaction in the Southern Ocean on a regional scale, as well as atmospheric and oceanic teleconnections on a global scale. ***