Variability and coherence of the Agulhas Undercurrent in a High-resolution Ocean General Circulation Model.

Biastoch, Arne , Beal, L., Lutjeharms, J.R.E. and Casal, T.G.D. (2009) Variability and coherence of the Agulhas Undercurrent in a High-resolution Ocean General Circulation Model. Open Access Journal of Physical Oceanography, 39 . pp. 2417-2435. DOI 10.1175/2009JPO4184.1.

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Abstract

The Agulhas Current system has been analyzed in a nested high-resolution ocean model and compared to observations. The model shows good performance in the western boundary current structure and the transports off the South African coast. This includes the simulation of the northward-flowing Agulhas Undercurrent. It is demonstrated that fluctuations of the Agulhas Current and Undercurrent around 50–70 days are due to Natal pulses and Mozambique eddies propagating downstream. A sensitivity experiment that excludes those upstream perturbations significantly reduces the variability as well as the mean transport of the undercurrent. Although the model simulates undercurrents in the Mozambique Channel and east of Madagascar, there is no direct connection between those and the Agulhas Undercurrent. Virtual float releases demonstrate that topography is effectively blocking the flow toward the north.

Document Type: Article
Keywords: Ocean circulation; Currents; General circulation models; Africa
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-TM Theory and Modeling
OceanRep > The Future Ocean - Cluster of Excellence
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1175/2009JPO4184.1
ISSN: 0022-3670
Projects: Future Ocean
Expeditions/Models/Experiments:
Date Deposited: 30 Nov 2009 11:33
Last Modified: 12 Apr 2018 10:30
URI: http://oceanrep.geomar.de/id/eprint/777

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