Vertical flow in the Southern Ocean estimated from individual moorings

Sévellec, F. and Garabato, A. C. Naveira and Brearley, J. A. and Sheen, K. L.

abstract: 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.

  author = {S\'{e}vellec, F. and Garabato, A. C. Naveira and Brearley, J. A. and Sheen, K. L.},
  title = {Vertical flow in the {Southern} {Ocean} estimated from individual moorings},
  journal = {J. Phys. Ocean.},
  year = {2015},
  pages = {2209--2200},
  volume = {45},
  issue = {9},
  doi = {10.1175/JPO-D-14-0065.1},
  url = {}