1 / 12

Antarctic Circumpolar Current

Antarctic Circumpolar Current. Philip Sontag. Thermohaline Circulation; “Mix-Master”. Antarctic Fronts. Convergence Divergence Patterns. Antarctic Circumpolar Curren t. Geostrophic Driven by prevailing westerly winds B alance of surface and bottom stresses

bethan
Download Presentation

Antarctic Circumpolar Current

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Antarctic Circumpolar Current Philip Sontag

  2. Thermohaline Circulation; “Mix-Master”

  3. Antarctic Fronts

  4. Convergence Divergence Patterns

  5. Antarctic Circumpolar Current • Geostrophic • Driven by prevailing westerly winds • Balance of surface and bottom stresses • Potential Vorticity and Bottom Topography

  6. Antarctic Polar Ice, Bottom Water Formation (600S) • Penetrative barrier – Albedo – Positive Feedback • Polynas • Origin, Shallow Weddel and Ross Seas • Stability of stratified ocean • Transport to western basin • Decrease CO2 uptake • Driven by Halocline • Melting, formation of ice • Sources: 1) Surface waters -> Continental Shelf 2) Remnants of Circumpolar deep waters

  7. Eddies • 20 km diameter –> jets • Primary mechanism for generating interface displacement • Divergence in Ekman transport • Sheered along flanks of jets

  8. Eddies and Jets, Ocean Storms • Focusing of eddies into narrow jet • ACC -> 2 to 3 narrow jets, sharp fronts • Meridional gradients of potential vorticity (PV) • Strong along Eastward • Weaker along Westward • Eastward and westward flow arise from local PV mixing • “PV staircase” • Merge and split, yet persistent • “Barrier” or “Blender”

  9. Drake Passage

  10. Implications for Primary Production

  11. Melting of Antarctic Shelves

  12. References • Hellmer, H. H., F. Kauker, et al. (2012). Twenty-first-century warming of a large Antarctic ice-shelf cavity by a redirected coastal current. 485: 225-228. • Knauss, J. A., Ed. (1997). Introduction to Physical Oceanography. Long Grove, IL, Waveland Press, Inc. • NASA/MODIS Rapid Response/Jeff Schmaltz. Caption Credit: Rebecca Lindsey, NASA Earth Observatory. http://www.nasa.gov/multimedia/imagegallery/image_feature_1509.html • Orsi, A. H., G. C. Johnson, et al. (1999). Circulation, mixing, and production of Antarctic Bottom Water. 43: 55-109. • Rintoul, S. R. and J. L. Bullister (1999). A late winter hydrographic section from Tasmania to Antarctica. 46: 1417-1454. • Stewart, R. H. (2008). Introduction To Physical Oceanography, Department of Oceanography Texas A & M University. • Thompson, A. F. (2008). The atmospheric ocean: eddies and jets in the Antarctic Circumpolar Current. 366: 4529-4541. • U.S. Geological Survey First published in the Encyclopedia of Earth March 30, 2010; Last revised Date June 11, 2012; Retrieved December 6, 2012 http://www.eoearth.org/article/Antarctic_Convergence?topic=49523

More Related