Vertical flow in the Southern Ocean estimated from individual moorings

Sévellec, F.; Naveira Garabato, A. C.; Brearley, J. A. ORCID: https://orcid.org/0000-0003-3700-8017; Sheen, K. L.. 2015 Vertical flow in the Southern Ocean estimated from individual moorings. Journal of Physical Oceanography, 45 (9). 2209-2220. 10.1175/JPO-D-14-0065.1

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Official URL: http://dx.doi.org/10.1175/JPO-D-14-0065.1

Abstract/Summary

In this study, we demonstrate that oceanic vertical velocities can be estimated from individual mooring measurements, even for non-stationary flow. This result is obtained under three assumptions: i. weak diffusion (Péclet number ≫1), ii. weak friction (Reynolds number ≫1), and iii. small inertial terms (Rossby number ≪1). The theoretical framework is applied to a set of 4 moorings located in the Southern Ocean. For this site, the diagnosed vertical velocities are highly variable in time, their standard deviation being one-to-two orders of magnitude greater than their mean. We demonstrate that the time-averaged vertical velocities are largely induced by geostrophic flow, and can be estimated from the time-averaged density and horizontal velocities. This suggests that local time-mean vertical velocities are primarily forced by the time-mean ocean dynamics, rather than by e.g. transient eddies or internal waves. We also show that, in the context of these four moorings, the time-mean vertical flow is consistent with stratified Taylor column dynamics in the presence of a topographic obstacle.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1175/JPO-D-14-0065.1
Programmes:	BAS Programmes > BAS Programmes 2015 > Polar Oceans
ISSN:	0022-3670
Additional Keywords:	geographic location/entity, Southern Ocean, circulation/dynamics, vertical motion, observational techniques and algorithms, buoy observations
Date made live:	14 Jul 2015 12:47 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/511314

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1175/JPO-D-14-0065.1

Programmes:

BAS Programmes > BAS Programmes 2015 > Polar Oceans

ISSN:

0022-3670

Additional Keywords:

geographic location/entity, Southern Ocean, circulation/dynamics, vertical motion, observational techniques and algorithms, buoy observations

Date made live:

14 Jul 2015 12:47 +0 (UTC)