Topic Area

LCDR (sel) Dave Carsten, USN

LT Neil Smith, USN

1. Agulhas Current strong, stable current running along the shelf break of South Africa.
2. Agulhas Rings spawned at the Alguhas Plateau region near tip South Africa &emdash; where Agulhas current undergoes retroflection.
3. Ring circulation down to Antarctic Intermediate Water level.
4. Agulhas rings observed to form at a rate of 4-8 rings per year.
5. Major transport mechanism for Indian Ocean water into Atlantic Ocean.
6. Agulhas current water source is a recirculation of Indian Ocean sub-gyre.
7. Natal Pulse is believed to create instability in flow required to shed a ring.
8. Ring formation is a slow process ~ 3 weeks..
9. Ring diameter at formation is ~300 km. Ring propagation speed is ~12 cm/s.
10. Features of the Agulhas retroflection:
    1. area commonly produces immense rogue waves &emdash; a hazard to even the largest supertankers
    2. Agulhas makes a right-angled turn to the south
    3. Agulhas rings carried off to the northwest in the Benguela Current
11. Experiments surveyed:
    1. KAPEX
    2. Benguela Current Experiment
    3. OCCAM
    4. AGAPE

Arhan, M. A., H. Mercier and J. R. E. Lutjeharms, 1999: The disparate evolution of three Agulhas rings in the South Atlantic Ocean, J. Phys. Res., 104, 20,987-21,005.

Chassignet, Eric, and Douglas Boudra. Dynamics of Agulhas Retroflection and Ring Formation in a Numerical Model. Part II. Energetics and Ring Formation. J. of Phys. Oceanog. February, 1988.

Garzoli, S. L., et al., 1999: Three Agulhas rings observed during the Benguela Current experiment, J. Phys. Res., 104, 20,971-20,985.

Lutjeharms, J.R.E., and R.C. van Ballegooyen, 1988: The Retroflection of the Agulhas Current, J. Phys. Oceanog., 18, 1570-1583.

Pichevin, Thierry, D. Nof, Johann Lutjeharms. Why are there Agulhas Rings? J. of Phys. Oceanog.. April, 1999.

Schmitz, W.J. Jr., 1996: On the World Ocean Circulation: Volume II, The Pacific and Indian Oceans/A Global Update, Woods Hole Oceanographic Institution Technical Report WHOI-96-08, Woods Hole, MA.

http://daac.gsfc.nasa.gov/CAMPAIGN_DOCS/OCDST/agulhas.html

http://www.aoml.noaa.gov/phod/benguela/index.html - results

http://www.ifm.uni-kiel.de/to/woce/agulhas/agape.html

http://triton.sea.uct.ac.za/kapex.htm

http://www.soc.soton.ac.uk/JRD/OCCAM/agulhas.html

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