SWOT-ACC, Satellite and ship-based investigation of mesoscale-submesoscale interactions in the Antarctic Circumpolar Current.

Benoit LEGRESY (CSIRO, Australia)

CoAuthors

Helen PHILLIPS (University of Tasmania, IMAS, Australia); Kurt POLZIN (WHOI, United States); Nathan BINDOFF (University of Tasmania, IMAS, Australia); Clement AUGER (CSIRO, Australia)

Event: 2019 Ocean Surface Topography Science Team Meeting

Session: Science III: Mesoscale and sub-mesoscale oceanography

Presentation type: Type Oral

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. In recent years, studies have pointed to fine-scale processes that are able to dominate biogeochemical transfers. During the 1-day repeat phase, one SWOT track will cross the ACC South of Tasmania, upstream from Macquarie Ridge, a highly energetic ocean environment. This region has a high signal-to-noise ratio in SWOT measurements compared to adjacent ACC areas. It is of great interest, with expected sub-mesoscale signals in the form of internal waves, sub-mesoscale eddies and other potential small-scale features while crossing some sharp fronts of the ACC. The daily-repeat SWOT measurement allows the detection of the coherence of features and their connection to in situ observations (ship-based, floats, moorings, drifters, gliders).
This area is one of 5 main hot-spots in the ACC where the Eddy Heat Flux is particularly strong and the place of a standing meander of the ACC. We have been investigating this area for meso-submeso-scale processes. An oceanographic cruise dedicated to explore the frontal physics at higher resolution was carried out in October-November 2018 in the area led by IMAS/CSIRO/ACE-CRC.
We show some results of the higher resolution sampling during this cruise, showing small scale dynamic height signals of significant (10cm) amplitude in the area.
We also show a spectral analysis of along track existing altimeter data pointing to a very favourable area for strong mesoscale - sub-mesoscale feature SNR.
We conclude with an inventory of elements pointing to the interest of the area which justifies to repeat a cruise during the fast sampling phase of SWOT, to transform the in-situ studies into a monitoring during the whole SWOT mission.

 

Oral presentation show times:

Room Start Date End Date
The Forum Wed, Oct 23 2019,17:00 Wed, Oct 23 2019,17:15
Benoit LEGRESY
CSIRO
Australia
benoit.legresy@csiro.au