Continental Shelf and Coastal Processes

Major axes of the M2 tidal ellipses across 4 latitude transects off of eastern Australia. Tidal velocities are small, but clearly internal tidal beams are propagating along and through these transects, Robertson
Major axes of the M2 tidal ellipses across 4 latitude transects off of eastern Australia.  Tidal velocities are small, but clearly internal tidal beams are propagating along and through these transects, Robertson

In the last decade, there have been a number of studies undertaken on the dynamics of coastal ocean processes off the coast of south-eastern Australia. Much work has focused on measurement and modelling of regional and coastal circulation together with the hydrological structure. Objectives have included understanding of the forcing effects (by the EAC and wind) on the response of the continental shelf waters at the surface, mid-water column, and bottom boundary layer regions.  At this scale, research into boundary current eddy –shelf interactions, upwelling and downwelling and Wave climate, including internal and coastally trapped waves around the NSW coast are the topics addressed under this theme.

The following high-level science questions will guide the NSW-IMOS observing strategy in this area:

Boundary Current/Shelf Interactions:

  • What are the influences of the boundary currents and the associated meso-scale and sub-meso-scale eddies and billows off NSW on the waters over the continental shelf and how do they impact cross shelf exchange and water properties?
  • How does the EAC interact with the continental shelf/slope break and topographic features (such as canyons) generating wakes, Taylor columns, upwelling, internal waves, and mixing?

Upwelling and Downwelling:

  • What are the frequency, magnitude, and drivers of upwelling/downwelling processes and slope water intrusions in the coastal waters off NSW and how do they influence cross shelf exchange of properties?
  • How does the EAC moderate the strength, extent, and variability of upwelling?
  • What is the role of canyons in upwelling by the EAC?
  • What are the distribution, variability and drivers of dense shelf outflows?

Shelf Currents:

  • What is the magnitude and variability (interannual, seasonal, and higher frequency) of shelf currents off NSW?
  • What are they dynamical drivers of shelf currents off NSW and how do they interact with the EAC and assumed EAC undercurrent?

Wave Processes:

  • What are the roles of internal and coastally trapped waves, including tides in continental shelf processes?
  • What is the tidal regime and how does it influence shelf processes?
  • What is the influence of coastally trapped waves on shelf circulations?
  • What is the contribution of the various wave processes to mixing over the shelf and at the shelf edge?
  • What is the contribution of internal tides and waves to on-shelf transport of nutrients and off-shelf transport of pollutants?
  • What are the range and concentrations of pollutants entering our coastal zone from catchment sources and how do they pose a threat to shelf biodiversity?
  • Quantify changes to beach topography and wave fields across different beach types before and after significant East Coast Low events?