The Leeuwin Current

1989 ◽  
pp. 230-254
Author(s):  
John A. Church ◽  
George R. Cresswell ◽  
J. Stuart Godfrey
Keyword(s):  
Leeuwin Current

Role of eddies in cooling the Leeuwin Current

2006 ◽  
Vol 33 (5) ◽  
Author(s):  
Catia M. Domingues ◽  
Susan E. Wijffels ◽  
Mathew E. Maltrud ◽  
John A. Church ◽  
Matthias Tomczak
Keyword(s):  
Leeuwin Current

scholarly journals Freshening anomalies in the Indonesian throughflow and impacts on the Leeuwin Current during 2010-2011

2015 ◽  
Vol 42 (20) ◽  
pp. 8555-8562 ◽  
Author(s):  
Ming Feng ◽  
Jessica Benthuysen ◽  
Ningning Zhang ◽  
Dirk Slawinski
Keyword(s):  
Indonesian Throughflow ◽  
Leeuwin Current

Mid Pleistocene arid shift in southern Australia, dated by magnetostratigraphy

Soil Research ◽  
2001 ◽  
Vol 39 (1) ◽  
pp. 89 ◽  
Author(s):  
Brad Pillans ◽  
Robert Bourman
Keyword(s):  
Marked Change ◽  
Source Area ◽  
Pronounced Change ◽  
Sea Levels ◽  
Leeuwin Current ◽  
Polarity Transition ◽  
Tasman Sea ◽  
Eastern Australia ◽  
Regional Climates ◽  
Regional Rainfall

In coastal sections at Hallett Cove and Sellicks Beach, south of Adelaide, and at Redbanks section on Kangaroo Island, the Brunhes/Matuyama polarity transition (780 ka) is identified in the strongly oxide-mottled Ochre Cove Formation. At all 3 sections, the Ochre Cove Formation is overlain by a calcareous grey-green aeolian clay, called Ngaltinga Clay, which in turn is overlain by calcareous sediments of the Taringa and Christies Beach Formations. The marked change from an oxide-dominated weathering regime to a carbonate-dominated weathering regime, estimated to have occurred at about 500–600 ka, is interpreted as a major arid shift in regional climates. Similar arid shifts are known from Lake Bungunnia in the Murray Basin and Lake Lefroy in southern Western Australia, where changes from lacustrine clays to evaporites and dune sediments are estimated to have occurred between 400 and 700 ka, and about 500 ka, respectively. An increase in aeolian dust accession in south-eastern Australia, consistent with increased aridity in the interior source area, occurred after 780 ka, and was probably coeval with increased dust input to Tasman Sea sediments since 350 ka. Between 600 and 900 ka, oxygen isotope fluctuations in deep-sea cores showed a pronounced change in frequency, from a 40 ka (obliquity dominated) to a 100 ka (eccentricity dominated) pattern. At the same time, glacial-interglacial amplitudes increased, with a marked enrichment of glacial d18O values consistent with larger continental based ice-sheets. Colder global temperatures, and lower sea levels during glacials, may have played a part in the mid Pleistocene arid shift recorded in southern Australia. Associated variations in the strength of the warm Leeuwin Current may also have affected regional rainfall patterns in southern Australia.

Dynamics of the Ningaloo Current off Point Cloates, Western Australia

2006 ◽  
Vol 57 (3) ◽  
pp. 291 ◽  
Author(s):  
Mun Woo ◽  
Charitha Pattiaratchi ◽  
William Schroeder
Keyword(s):  
Numerical Model ◽  
Continental Shelf ◽  
Western Australia ◽  
Bottom Topography ◽  
Volume Transport ◽  
Relative Strength ◽  
Cross Sectional ◽  
Leeuwin Current ◽  
The North ◽  
Tropical Water

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.

Seasonal variation in the long-term warming trend in water temperature off the Western Australian coast

2009 ◽  
Vol 60 (2) ◽  
pp. 129 ◽  
Author(s):  
N. Caputi ◽  
S. de Lestang ◽  
M. Feng ◽  
A. Pearce
Keyword(s):  
Seasonal Variation ◽  
Indian Ocean ◽  
Water Temperature ◽  
West Coast ◽  
Climate Models ◽  
Warming Trend ◽  
Temperature Cycle ◽  
Rock Lobster ◽  
Leeuwin Current ◽  
The Indian Ocean

Previous studies have demonstrated that one area of greatest increase in surface sea temperatures (SST) (0.02°C per year) in the Indian Ocean over the last 50 years occurs off the lower west coast of Australia, an area dominated by the Leeuwin Current. The present paper examines water temperature trends at several coastal sites since the early 1970s: two rock lobster puerulus monitoring sites in shallow water (<5 m); four sites from a monitoring program onboard rock lobster vessels that provide bottom water temperature (<36 m); and an environmental monitoring site at Rottnest (0–50 m depth). Two global SST datasets are also examined. These data show that there was a strong seasonal variation in the historic increases in temperature off the lower west coast of Australia, with most of the increases (0.02–0.035°C per year) only focussed on 4–6 months over the austral autumn–winter with little or no increase (<0.01°C per year) apparent in the austral spring–summer period. These increases are also apparent after taking into account the interannual variation in the strength of the Leeuwin Current. The warming trend results in a change to the seasonal temperature cycle over the decades, with a delay in the peak in the temperature cycle during autumn between the 1950s and 2000s of ~10–20 days. A delay in the timing of the minimum temperature is also apparent at Rottnest from August–September to October. This seasonal variation in water temperature increases and its effect on the annual temperature cycle should be examined in climate models because it provides the potential to better understand the specific processes through which climate change and global warming are affecting this region of the Indian Ocean. It also provides an opportunity to further test the climate models to see whether this aspect is predicted in the future projections of how increases will be manifest. Any seasonal variation in water temperature increase has important implications for fisheries and the marine ecosystem because it may affect many aspects of the annual life cycle such as timing of growth, moulting, mating, spawning and recruitment, which have to be taken into account in the stock assessment and management of fisheries.

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