scholarly journals Rates and mechanisms of turbulent dissipation and mixing in the Southern Ocean: Results from the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES)

2013 ◽  
Vol 118 (6) ◽  
pp. 2774-2792 ◽  
Author(s):  
K. L. Sheen ◽  
J. A. Brearley ◽  
A. C. Naveira Garabato ◽  
D. A. Smeed ◽  
S. Waterman ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Turbulent Dissipation ◽  
Isopycnal Mixing

scholarly journals Jet–Topography Interactions Affect Energy Pathways to the Deep Southern Ocean

2017 ◽  
Vol 47 (7) ◽  
pp. 1799-1816 ◽  
Author(s):  
Alice Barthel ◽  
Andrew McC. Hogg ◽  
Stephanie Waterman ◽  
Shane Keating
Keyword(s):  
Southern Ocean ◽  
Ocean Circulation ◽  
Baroclinic Instability ◽  
Deep Ocean ◽  
Ocean Model ◽  
Shear Instability ◽  
Horizontal Shear ◽  
Mean Flow ◽  
Flat Bottom ◽  
Turbulent Dissipation

AbstractIn the Southern Ocean, strong eastward ocean jets interact with large topographic features, generating eddies that feed back onto the mean flow. Deep-reaching eddies interact with topography, where turbulent dissipation and generation of internal lee waves play an important role in the ocean’s energy budget. However, eddy effects in the deep ocean are difficult to observe and poorly characterized. This study investigates the energy contained in eddies at depth, when an ocean jet encounters topography. This study uses a two-layer ocean model in which an imposed unstable jet encounters a topographic obstacle (either a seamount or a meridional ridge) in a configuration relevant to an Antarctic Circumpolar Current frontal jet. The authors find that the presence of topography increases the eddy kinetic energy (EKE) at depth but that the dominant processes generating this deep EKE depend on the shape and height of the obstacle as well as on the baroclinicity of the jet before it encounters topography. In cases with high topography, horizontal shear instability is the dominant source of deep EKE, while a flat bottom or a strongly sheared inflow leads to deep EKE being generated primarily through baroclinic instability. These results suggest that the deep EKE is set by an interplay between the inflowing jet properties and topography and imply that the response of deep EKE to changes in the Southern Ocean circulation is likely to vary across locations depending on the topography characteristics.

scholarly journals Modification of turbulent dissipation rates by a deep Southern Ocean eddy

2015 ◽  
Vol 42 (9) ◽  
pp. 3450-3457 ◽  
Author(s):  
K. L. Sheen ◽  
J. A. Brearley ◽  
A. C. Naveira Garabato ◽  
D. A. Smeed ◽  
L. St. Laurent ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Turbulent Dissipation ◽  
Dissipation Rates

scholarly journals Eddy-Induced Modulation of Turbulent Dissipation over Rough Topography in the Southern Ocean

2013 ◽  
Vol 43 (11) ◽  
pp. 2288-2308 ◽  
Author(s):  
J. Alexander Brearley ◽  
Katy L. Sheen ◽  
Alberto C. Naveira Garabato ◽  
David A. Smeed ◽  
Stephanie Waterman
Keyword(s):  
Southern Ocean ◽  
Internal Wave ◽  
Ocean Circulation ◽  
Wave Energy ◽  
Bottom Topography ◽  
Temporal Correlation ◽  
Drake Passage ◽  
Wave Radiation ◽  
Bottom Current ◽  
Turbulent Dissipation

Abstract Mesoscale eddies are universal features of the ocean circulation, yet the processes by which their energy is dissipated remain poorly understood. One hypothesis argues that the interaction of strong geostrophic flows with rough bottom topography effects an energy transfer between eddies and internal waves, with the breaking of these waves causing locally elevated dissipation focused near the sea floor. This study uses hydrographic and velocity data from a 1-yr mooring cluster deployment in the Southern Ocean to test this hypothesis. The moorings were located over a small (~10 km) topographic obstacle to the east of Drake Passage in a region of high eddy kinetic energy, and one was equipped with an ADCP at 2800-m depth from which internal wave shear variance and dissipation rates were calculated. Examination of the ADCP time series revealed a predominance of upward-propagating internal wave energy and a significant correlation (r = 0.45) between shear variance levels and subinertial near-bottom current speeds. Periods of strong near-bottom flow coincided with increased convergence of eddy-induced interfacial form stress in the bottom 1500 m. Predictions of internal wave energy radiation were made from theory using measured near-bottom current speeds, and the mean value of wave radiation (5.3 mW m−2) was sufficient to support the dissipated power calculated from the ADCP. A significant temporal correlation was also observed between radiated and dissipated power. Given the ubiquity of strong eddy flows and rough topography in the Southern Ocean, the transfer from eddy to internal wave energy is likely to be an important term in closing the ocean energy budget.

Prey-field use by a Southern Ocean top predator: enhanced understanding using integrated datasets

2015 ◽  
Vol 526 ◽  
pp. 169-181 ◽  
Author(s):  
M Bedford ◽  
J Melbourne-Thomas ◽  
S Corney ◽  
T Jarvis ◽  
N Kelly ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Top Predator

Traits structure copepod niches in the North Atlantic and Southern Ocean

2018 ◽  
Vol 601 ◽  
pp. 109-126 ◽  
Author(s):  
N McGinty ◽  
AD Barton ◽  
NR Record ◽  
ZV Finkel ◽  
AJ Irwin
Keyword(s):  
Southern Ocean ◽  
North Atlantic ◽  
The North ◽  
The North Atlantic
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