In:
Journal of Physical Oceanography, American Meteorological Society, Vol. 46, No. 7 ( 2016-07), p. 2005-2027
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 m 2 s −1 at 700 m decreasing to 990 ± 200 m 2 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 m 2 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 m 2 s −1 .
Type of Medium:
Online Resource
ISSN:
0022-3670
,
1520-0485
DOI:
10.1175/JPO-D-15-0207.1
Language:
Unknown
Publisher:
American Meteorological Society
Publication Date:
2016
detail.hit.zdb_id:
2042184-9
detail.hit.zdb_id:
184162-2
Permalink
