The Open UniversitySkip to content
 

Physical oceanographic conditions to the northwest of the sub-Antarctic Island of South Georgia

Brandon, M. A.; Murphy, E. J.; Trathan, P. N. and Bone, D. G. (2000). Physical oceanographic conditions to the northwest of the sub-Antarctic Island of South Georgia. Journal of Geophysical Research: Oceans, 105(C10) pp. 23983–23996.

URL: http://www.agu.org/journals/jc/v105/iC10/
Google Scholar: Look up in Google Scholar

Abstract

Ocean physics is a key aspect of the operation of island ecosystems, yet the hydrodynamics is sometimes poorly understood. A high-resolution oceanographic survey to the north of South Georgia identified two water masses. These are South Georgia Shelf Water (SGSW) and Antarctic Zone Water (AZW). At the surface, SGSW is both colder and fresher than AZW; at the near-surface temperature minimum these differences are reversed. There are two causes: SGSW is close to the island and has an additional contribution to the heat and salt balance from increased precipitation and island runoff, and second, AZW has advected from higher latitudes. Both of these mechanisms imply SGSW is retained around the island. Between these water masses is a variable width frontal region that has a mixture of both water masses. In general terms, the mean current of the AZW is to the west. In the SGSW the general flow also appears to be to the west, but at reduced magnitude; there is evidence of a stronger westerly current close to the shore. In both water masses there are easterly surface currents most likely driven by the prevailing wind. An approximation for the limit of SGSW is that it is constrained to water depths <500 m, A significant deviation is caused by an anticyclonic flow around a prominent bank that can be associated with significant, upwelling. Finally, we comment on the ecological significance of the system observed.

Item Type: Journal Article
ISSN: 0148-0227
Academic Unit/Department: Science > Environment, Earth and Ecosystems
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Item ID: 12099
Depositing User: Mark Brandon
Date Deposited: 20 Oct 2008 12:03
Last Modified: 02 Dec 2010 20:14
URI: http://oro.open.ac.uk/id/eprint/12099
Share this page:

Actions (login may be required)

View Item
Report issue / request change

Policies | Disclaimer

© The Open University   + 44 (0)870 333 4340   general-enquiries@open.ac.uk