The ocean currents of the SA-IMOS Node region appear to be influenced by El Nino-Southern Oscillation (ENSO) events in the Pacific, whereby a relaxation of equatorial winds drives an eastward flow of deep warm water.  It is believed that this enhances wind-forced upwelling and reduces wintertime pole-ward shelf currents along Australia’s west and southern shelves.  Climate related changes of winds in the Pacific, Indian and Southern Oceans may also be important to changes in the strength of boundary currents that impact on those of the SA-IMOS Node region.  The future prognosis for climate change for southern Australian waters (CSIRO Global Climatic Model 3.5) includes a strengthening of upwelling favourable winds off South Australia.  An additional form of large scale forcing in the area involves the Antarctic Circumpolar Wave, which it is suggested results from an interaction of the oceanic and atmospheric boundary layers, and has a four year period and amplitude of 0.5C off South Australia (White and Peterson 1996). The impact of this wave on shelf and slope circulation is not known. 

Key Science Questions

El Nino-Southern Oscillation

• What is the temporal and spatial variability and nature of the Flinders Current/Leeuwin Current and coastal shelf boundary currents including effects of seasonal and ENSO forcing?