Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences
RESEARCH ARTICLE

Thermal structure above the Perth Canyon reveals Leeuwin Current, Undercurrent and weather influences and the potential for upwelling

Susan J. Rennie A , Robert D. McCauley A C and Charitha B. Pattiaratchi B
+ Author Affiliations
- Author Affiliations

A Centre for Marine Science and Technology, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia.

B Centre for Water Research, Mailstop MO15, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.

C Corresponding author. Email: r.mccauley@cmst.curtin.edu.au

Marine and Freshwater Research 57(8) 849-861 https://doi.org/10.1071/MF05247
Submitted: 13 December 2005  Accepted: 11 September 2006   Published: 28 November 2006

Abstract

The Perth Canyon is a focal feeding area for pygmy blue whales on the Western Australian coast. Studies aimed at elaborating oceanographic mechanisms within the canyon were conducted between 2002 and 2005. Strings of temperature loggers set around the canyon rim were used to examine the water column’s response to climatological forcing, current meanders, upwelling and downwelling. Six moorings were positioned on a plateau in 500 m of water on the northern canyon rim, and one was positioned at the canyon head. Loggers were positioned to sample the whole water column, including the Leeuwin Current and Undercurrent. Moorings revealed spatial temperature differences between the plateau and canyon head. Observed temperature features ranged temporally from seasonal to <1 day. Seasonal changes in water temperature agreed with published Leeuwin Current studies: for example, mixed layer and stratification changes were apparent. Other observed temperature changes were related to Leeuwin Current movement and wind forcing such as the summer sea breeze and winter storms. Storms induced mixing, re-stratification, downwelling and upwelling as the wind changed direction and strength. Changes lasting a day were associated with diurnal sea breezes, internal waves and possibly solitary waves. Bottom loggers indicated that upwelling and downwelling events each occurred up to 20% of the time.

Extra keywords: stratification, submarine canyons, temperature measurement.


Acknowledgments

Funding for this study was provided by the WAXA (Western Australian Exercise Area) Blue Whale Project, which Australian Defence Forces funded in order to study the pygmy blue whales and their habitat. Paul Pettorini and the crew of the fishing vessel ‘Reliance II’ were crucial for mooring deployment and recovery. The Centre for Whale Research assisted with mooring deployments. The Australian Bureau of Meteorology supplied the meteorological data from the Rottnest Island station. Satellite SST images were accessed from the Western Australian Department of Land Information through the Land Online website at www.landonline.com.au, with additional SST images obtained from POET at http://poet.jpl.nasa.gov.


References

Ardhuin, F. , Pinot, J. M. , and Tintoré, J. (1999). Numerical study of the circulation in a steep canyon off the Catalan coast (western Mediterranean). Journal of Geophysical Research 104((C5)), 11115–11135.
CrossRef |

Bosley, K. L. , Lavelle, J. W. , Brodeur, R. D. , Wakefield, W. W. , Emmett, R. L. , Baker, E. T. , and Rehmke, K. M. (2004). Biological and physical processes in and around Astoria submarine Canyon, Oregon, USA. Journal of Marine Systems 50, 21–37.
CrossRef |

Carter, G. S. , and Gregg, M. C. (2002). Intense, variable mixing near the head of Monterey Submarine Canyon. Journal of Physical Oceanography 32(11), 3145–3165.
CrossRef |

Cresswell, G. R. (1996). The Leeuwin Current near Rottnest Island, Western Australia. Marine and Freshwater Research 47, 483–487.
CrossRef |

Cresswell, G. R. , and Griffin, D. A. (2004). The Leeuwin Current, eddies and sub-Antarctic waters off south-western Australia. Marine and Freshwater Research 55, 267–276.
CrossRef |

Feng, M. , Meyers, G. , Pearce, A. F. , and Wijffels, S. (2003). Annual and interannual variations of the Leeuwin Current at 32°S. Journal of Geophysical Research 108(C11), 3355.
CrossRef |

Fieux, M. , Molcard, R. , and Morrow, R. (2005). Water properties and transport of the Leeuwin Current and Eddies off Western Australia. Deep-Sea Research. Part I, Oceanographic Research Papers 52, 1617–1635.
CrossRef |

Gersbach, G. H. , Pattiaratchi, C. B. , Ivey, G. N. , and Cresswell, G. R. (1999). Upwelling on the south-west coast of Australia—source of the Capes Current? Continental Shelf Research 19, 363–400.
CrossRef |

Godfrey, J. S. , and Ridgway, K. R. (1985). The large-scale environment of the poleward-flowing Leeuwin Current, Western Australia: Longshore steric height gradients, wind stresses and geostrophic flow. Journal of Physical Oceanography 15, 481–494.
CrossRef |

Hanson, C. E. , Pattiaratchi, C. B. , and Waite, A. M. (2005). Seasonal production regimes off south-western Australia: Influence of the Capes and Leeuwin Currents on phytoplankton dynamics. Marine and Freshwater Research 56, 1011–1026.
CrossRef |

Hickey B. M. (1995). Coastal submarine canyons. In ‘Aha Huliko’a Proceedings: Flow-Topography Interactions’. (Ed. P. Muller.) pp. 95–110. (Office of Naval Research: Honolulu, HI.)

Hickey, B. M. (1997). The response of a steep-sided, narrow canyon to time-variable wind forcing. Journal of Physical Oceanography 27, 697–726.
CrossRef |

Hughes, T. M. C. , Weaver, A. J. , and Godfrey, J. S. (1992). Thermohaline forcing of the Indian Ocean by the Pacific Ocean. Deep-Sea Research. Part A, Oceanographic Research Papers 39(6), 965–995.
CrossRef |

Jones I. S. F., Cato D. H., Hamilton L. J., and Scott B. D. (1996). Site survey for an ocean engineering project west of Perth for July to September 1992. Report no. DSTO-TR-0459. Defence Science and Technology Organisation (DSTO) Aeronautical and Marine Research Laboratory: Melbourne.

Jordi, A. , Orfila, A. , Basterretxea, G. , and Tintoré, J. (2005). Shelf-slope exchanges by frontal variability in a steep submarine canyon. Progress in Oceanography 66, 120–141.
CrossRef |

Klinck, J. M. (1996). Circulation near submarine canyons: A modelling study. Journal of Geophysical Research 101((C1)), 1211–1233.
CrossRef |

Pattiaratchi, C. B. , Hegge, B. , Gould, J. , and Eliot, I. (1997). Impact of sea-breeze activity on nearshore and foreshore processes in southwestern Australia. Continental Shelf Research 17(13), 1539–1560.
CrossRef |

Pearce, A. F. , and Pattiaratchi, C. B. (1999). The Capes Current: a summer countercurrent flowing past Cape Leeuwin and Cape Naturaliste, Western Australia. Continental Shelf Research 19, 401–420.
CrossRef |

Peliz, Á. , Dubert, J. , Haidvogel, D. B. , and Le Cann, B. (2003). Generation and unstable evolution of a density-driven Eastern Poleward Current: The Iberian Poleward Current. Journal of Geophysical Research 108(C8), 3268.
CrossRef |

Rennie S. J. (2005). Oceanographic processes in the Peth Canyon and their impact on productivity. Ph.D. Thesis, Curtin University of Technology, Perth. Available online at: http://adt.curtin.edu.au/theses/available/adt-WCU20060620.104512/ [verified October 2006].

Ridgway, K. R. , and Condie, S. A. (2004). The 5500-km-long boundary flow off western and southern Australia. Journal of Geophysical Research C: Oceans 109,
CrossRef |

She, J. , and Klinck, J. M. (2000). Flow near submarine canyons driven by constant winds. Journal of Geophysical Research 105((C12)), 28671–28694.
CrossRef |

Skliris, N. , Goffart, A. , Hecq, J. H. , and Djenidi, S. (2001). Shelf-slope exchanges associated with a steep submarine canyon off Calvi (Corsica, NW Mediterranean Sea): A modeling approach. Journal of Geophysical Research 106((C9)), 19883–19901.
CrossRef |

Skliris, N. , Lacroix, G. , and Djenidi, S. (2004). Effects of extreme meteorological conditions on coastal dynamics near a submarine canyon. Continental Shelf Research 24, 1033–1045.
CrossRef |

Smith, R. L. , Huyer, A. , Godfrey, J. S. , and Church, J. A. (1991). The Leeuwin Current off Western Australia, 1986–1987. Journal of Physical Oceanography 21(2), 323–345.
CrossRef |

Sobarzo, M. , Figueroa, M. , and Djurfeldt, L. (2001). Upwelling of subsurface water into the rim of the Biobío submarine canyon as a response to surface winds. Continental Shelf Research 21, 279–299.
CrossRef |

Thompson, R. O. R. Y. (1984). Observations of the Leeuwin Current off Western Australia. Journal of Physical Oceanography 14, 623–628.
CrossRef |

Thompson, R. O. R. Y. , and Veronis, G. (1983). Poleward boundary current of Western Australia. Australian Journal of Marine and Freshwater Research 34, 173–185.
CrossRef |

von der Borch, C. C. (1968). Southern Australian submarine canyons: Their distribution and ages. Marine Geology 6(2), 269–279.


Woo M. (2005). Summer circulation and water masses along the West Australian coast. Ph.D. Thesis, University of Western Australia, Perth.

Woo, M. , Pattiaratchi, C. B. , and Schroeder, W. (2006). Summer surface circulation along the Gascoyne continental shelf, Western Australia. Continental Shelf Research 26, 132–152.
CrossRef |



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