Circulation and Stirring in the Southeast Pacific Ocean and the Scotia Sea Sectors of the Antarctic Circumpolar Current
Name
Circulation and stirring.pdf
Size
8.01 MB
Format
Adobe PDF
Checksum (MD5)
653468910aeaf2a0d88235c9b8b3d7f8
Author(s)
Balwada, Dhruv
Speer, Kevin G.
Owens, W. Brechner
Marshall, John C
Ferrari, Raffaele
LaCasce, Joseph H., 1964-
Date Issued
June 2016
Journal
Journal of Physical Oceanography
Publisher
American Meteorological Society
Citation
Balwada, Dhruv; Speer, Kevin G.; LaCasce, Joseph H.; Owens, W. Brechner; Marshall, John and Ferrari, Raffaele. “ Circulation and Stirring in the Southeast Pacific Ocean and the Scotia Sea Sectors of the Antarctic Circumpolar Current a .” Journal of Physical Oceanography 46, no. 7 (July 2016): 2005–2027. © 2016 American Meteorological Society
Version
Final published version
Abstract
The large-scale middepth circulation and eddy diffusivities in the southeast Pacific Ocean and Scotia Sea sectors between 110° and 45°W of the Antarctic Circumpolar Current (ACC) are described based on a subsurface quasi-isobaric RAFOS-float-based Lagrangian dataset. These RAFOS float data were collected during the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES). The mean flow, adjusted to a common 1400-m depth, shows the presence of jets in the time-averaged sense with speeds of 6 cm s⁻¹ in the southeast Pacific Ocean and upward of 13 cm s−¹ in the Scotia Sea. These jets appear to be locked to topography in the Scotia Sea but, aside from negotiating a seamount chain, are mostly free of local topographic constraints in the southeast Pacific Ocean. The eddy kinetic energy (EKE) is higher than the mean kinetic energy everywhere in the sampled domain by about 50%. The magnitude of the EKE increases drastically (by a factor of 2 or more) as the current crosses over the Hero and Shackleton fracture zones into the Scotia Sea. The meridional isopycnal stirring shows lateral and vertical variations with local eddy diffusivities as high as 2800 ± 600 m2 s⁻¹ at 700 m decreasing to 990 ± 200 m² s⁻¹ at 1800 m in the southeast Pacific Ocean. However, the cross-ACC diffusivity in the southeast Pacific Ocean is significantly lower, with values of 690 ± 150 and 1000 ± 200 m² s⁻¹ at shallow and deep levels, respectively, due to the action of jets. The cross-ACC diffusivity in the Scotia Sea is about 1200 ± 500 m² s⁻¹.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1175/JPO-D-15-0207.1
