ship-based
(proposed)
infrastructure
(proposed)
ship-based
(confirmed)
infrastructure
(confirmed)
mooring

ACC-SMST

What is the contribution of finescales in heat fluxes in the ACC standing meander south of Tasmania? 

The Southern Ocean is a major player in the heat and carbon uptake and transport, with the Antarctic Circumpolar Current (ACC) being the strongest current in the world, with hotspots occurring where the current interacts with topographic features. 

The region called ACC standing meander South of Tasmania (ACC-SMST) there is one of these hot spots with a high eddy heat flux. The objective of the ACC-SMST campaign is to describe the dynamics of the ACC in this region, including current-topography interactions and smaller scale dynamics testing using observations and modelling. The Fast Sampling Phase crosses the ACC right in the meander hotspot and the site of strong meso and sub-meso scale signals, including significant internal tides, internal waves, submesoscale eddies and a strong wave regime. 

In situ observations are being planned with a nominal plan to have moorings deployed, floats, drifters and gliders profiling across the area on top of a full oceanographic cruise which would do intense section profiling and shallow CTD and other sampling on top of underway Physics and BGC. The campaign will benefit from the concomitant in-situ/satellite observations and smaller scale processes understanding to better monitor the heat fluxes in the ACC-SMST and circumpolar over the whole science phase of the satellite. It is planned for the early science phase taking advantage of the latitude factor which makes coverage of the area every 5 days, allows for a synoptic SWOT coverage to interpret and follow the smaller scale features and benefit from the Fast sampling phase 1 day repeat SWOT data to solve for and map the stationary internal tides.

The investigations carried out within the ACC-SMTS region will be put in the context of a larger investigation of the Antarctic Circumpolar Current dynamics in a circumpolar view, taking advantage of the higher resolution offered by SWOT.  

The ACC-SMST campaign represents a unique effort to observe some of the most energetic ocean signals in the ACC where the measurements from SWOT may be noisier given the large waves regime while in situ measurements are always a challenge in the Southern Ocean. 

Surface currents (left panel) and relative vorticity ( ζ=vxuy) normalized by Coriolis frequency (f) (right panel) for the ACC-SMST study site with SWOT grid overlaid (black lines). Images were generated using output from a high-resolution MITgcm simulation and are instantaneous snapshots from 1 July 2012.

Principal investigators:  Benoit Legresy (benoit.legresy@csiro.au) (Climate Science Centre, CSIRO Australia), Helen Phillips (h.a.phillips@utas.edu.au) (IMAS, University of Tasmania, Australia), Maxim Nikurashin (maxim.nikurashin@utas.edu.au) (IMAS, University of Tasmania, Australia), Steve Rintoul (Steve.Rintoul@csiro.au) (Climate Science Centre, CSIRO, Australia), Kurt Polzin (kpolzin@whoi.edu) (Woods Hole Oceanographic Institution, USA), Randolph Watts (randywatts@uri.edu) (University of Rhode Island, USA), Nathan Bindoff (n.bindoff@utas.edu.au) (IMAS, University of Tasmania, Australia), Rosemary Morrow (Rosemary.Morrow@legos.obs-mip.fr) (LEGOS, France). 

Contact point for the study site: Benoit Legresy (benoit.legresy@csiro.au).