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RESEARCH FORUM
Contents Vol 57(3)

Dynamics of the Ningaloo Current off Point Cloates, Western Australia

Mun Woo A , Charitha Pattiaratchi A C and William Schroeder B
+ Author Affiliations
- Author Affiliations

A School of Environmental Systems Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.

B Marine Science Program, Dauphin Island Sea Lab, The University of Alabama, 101 Bienville Blvd, Dauphin Island, AL 36528-4603, USA.

C Corresponding author. Email: chari.pattiaratchi@uwa.edu.au

Marine and Freshwater Research 57(3) 291-301 https://doi.org/10.1071/MF05106
Submitted: 31 May 2005  Accepted: 6 March 2006   Published: 1 May 2006

Abstract

The Ningaloo Current (NC) is a wind-driven, northward-flowing current present during the summer months along the continental shelf between the latitudes of 22° and 24°S off the coastline of Western Australia. The southward flowing Leeuwin Current is located further offshore and flows along the continental shelf break and slope, transporting warm, relatively fresh, tropical water poleward. A recurrent feature, frequently observed in satellite images (both thermal and ocean colour), is an anti-clockwise circulation located offshore Point Cloates. Here, the seaward extension of the coastal promontory blocks off the broad, gradual southern shelf, leaving only a narrow, extremely steep shelf to the north. The reduction in the cross-sectional area, from the coast to the 50 m contour, between southward and northward of the promontory is ~80%. Here, a numerical model study is undertaken to simulate processes leading to the development of the recirculation feature offshore Point Cloates. The numerical model output reproduced the recirculation feature and indicated that a combination of southerly winds, and coastal and bottom topography, off Point Cloates is responsible for the recirculation. The results also demonstrated that stronger southerly winds generated a higher volume transport in the NC and that the recirculation feature was dependent on the wind speed, with stronger winds decreasing the relative strength of the recirculation.

Extra keywords: coastal water masses, Indian Ocean.


Acknowledgements

We thank the Captain, crew and staff of the RV Franklin for the successful execution of the voyage FR10/00. This work was funded by a UWA Research Grant, a UWA Vice Chancellor's Discretionary Grant and a UWA University Postgraduate Scholarship. This contribution is Centre for Water Research reference ED 1900 MW.


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