DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean

Lead Research Organisation: NERC British Antarctic Survey
Department Name: Science Programmes


Detailed in Lead Institution (NOC) Proposal


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Boland E (2012) The Formation of Nonzonal Jets over Sloped Topography in Journal of Physical Oceanography

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Brearley J (2017) Controls on turbulent mixing on the West Antarctic Peninsula shelf in Deep Sea Research Part II: Topical Studies in Oceanography

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Cusack J (2017) Observation of a Large Lee Wave in the Drake Passage in Journal of Physical Oceanography

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Cusack J (2020) Observed Eddy-Internal Wave Interactions in the Southern Ocean in Journal of Physical Oceanography

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Jiang M (2019) Fe sources and transport from the Antarctic Peninsula shelf to the southern Scotia Sea in Deep Sea Research Part I: Oceanographic Research Papers

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