DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean
Lead Research Organisation:
British Antarctic Survey
Department Name: Science Programmes
Abstract
Detailed in Lead Institution (NOC) Proposal
Organisations
Publications
Vernet M
(2019)
The Weddell Gyre, Southern Ocean: Present Knowledge and Future Challenges
in Reviews of Geophysics
Trossman D
(2015)
Internal lee wave closures: Parameter sensitivity and comparison to observations
in Journal of Geophysical Research: Oceans
Thompson A
(2012)
Jets and Topography: Jet Transitions and the Impact on Transport in the Antarctic Circumpolar Current
in Journal of Physical Oceanography
Sévellec F
(2019)
Observing the Local Emergence of the Southern Ocean Residual-Mean Circulation
in Geophysical Research Letters
Sheen K
(2015)
Modification of turbulent dissipation rates by a deep Southern Ocean eddy
in Geophysical Research Letters
Sallée J
(2012)
Localized subduction of anthropogenic carbon dioxide in the Southern Hemisphere oceans
in Nature Geoscience
Roemmich D
(2019)
On the Future of Argo: A Global, Full-Depth, Multi-Disciplinary Array
in Frontiers in Marine Science
Polzin K
(2014)
Boundary mixing in O rkney P assage outflow
in Journal of Geophysical Research: Oceans
| Description | Controls on the spreading and mixing of dense waters from Antarctica Deep mixing in the Southern Ocean is an important process in closing the lower limb of the oceanic overturning circulation, with implications for deep ocean ventilation and global climate. Several years of ship-based measurements in the Scotia Sea (Southern Ocean) were analysed, and the episodic presence of very dense layers at the seabed was discovered. These layers had vertical gradients in temperature and density that are as strong as those in the near-surface Southern Ocean, and are caused by water intermittently spilling across a ridge at the entrance to the Scotia Sea and becoming trapped in deep trenches. Using measurements of dissolved tracers, one such layer was found to have been trapped for at least 3-4 years. This enabled vertical mixing to be calculated, and it was found that the rate of mixing that the layer had been subjected to was substantially less than the very strong basin-average mixing reported previously. It was concluded that deep mixing in the Scotia Sea is significantly spatially structured, with the majority of the mixing occurring as the water crosses the ridge to enter the basin. Similar layers are observed outside the Scotia Sea, indicating that the same controls on the spreading and mixing of deep ocean waters may be widespread. |
| Exploitation Route | See NE/E007058/1 |
| Sectors | Environment |
| Description | See NE/E007058/1 |
| First Year Of Impact | 2010 |
| Sector | Other |