Tides of the Antarctic Peninsula: Implications for mixing and sea-ice concentration

Laurie Padman¹, Lana Erofeeva², (TBD)

¹ Earth & Space Research, Corvallis, OR: padman@esr.org; (541) 753-6695

²Oregon State University, Corvallis OR

Manuscript proposed for 2^nd SO GLOBEC Special Issue, DSR2

We use a high-resolution (~2 km) model of barotropic tides for the seas around the Antarctic Peninsula (Amundsen, Bellingshausen, and western Weddell) to investigate the role of tidal currents on the general oceanography and sea-ice characteristics of the region. The high resolution allows, for the first time, a reasonable representation of currents within the narrow channels between islands, and between islands and the coast. Spatial variability of currents is large. In the southern portion of the western Antarctic Peninsula (wAP) continental shelf, tidal currents are typically less than 5 cm/s. Currents are large, however, around the South Shetland Islands, within Antarctic Sound, and east from Joinville Island along portions of the South Scotia Ridge. Mean current speeds sometimes exceed 50 cm/s in these regions. We anticipate that ocean turbulence will be high in regions of strong tidal flows, with mixing arising from benthic friction and from generation of baroclinic tides and other internal waves. Mixing enhances the flux of oceanic heat from the warm intermediate waters up to the surface mixed layer, where it can be vented to the atmosphere or melt sea-ice. Mixing also brings nutrients up from intermediate waters to the photic zone. The periodic divergence of ocean stress applied by tidal currents to the sea-ice base increases the area-averaged open-water fraction in the sea-ice pack, allowing for more rapid sea-ice formation in fall and winter, and more rapid sea-ice decay in spring and summer through solar absorption into leads.

STATUS UPDATE:
Title and abstract received on 06/02/05.