Advection of baroclinic eddies by depth mean flow

Abstract

Observed zonal propagation speeds of nonlinear eddies, derived using an eddy tracking algorithm, are compared with the classical long Rossby wave speed, Doppler shifted by just the depth mean velocity, the latter obtained from annual mean hydrography and an ocean atlas. Despite neglecting any Doppler shift from baroclinic background flows, the correspondence between observed eddy propagation speeds and theoretical long Rossby wave phase speeds is improved in the Antarctic Circumpolar Current region, where both show eastward propagation at speeds of 1-3 cm s −1 , although the observed eastward eddy propagation speeds are systematically lower than the predicted Rossby wave phase speeds.

Temporal Changes in the Antarctic Circumpolar Current: Implications for the Antarctic Continental Shelves

“…As Morrow et al (2004) illustrate, most eddies in the ocean migrate meridionally and westward over their lifetimes, with warm-core (anticyclonic) eddies moving equatorward and cold-core (cyclonic) eddies moving poleward. In the Southern Ocean, eddies are advected eastward by the ACC instead of westward (e.g., Klocker and Marshall, 2014). As a result of the eastward motion, the meridional migration is also reversed (U. Zajaczkovski, Scripps Institution of Oceanography, pers.…”

A regime diagram for ocean geostrophic turbulence

“…11This approximation neglects the advection of eddies by the depth‐averaged mean flow, as described in Klocker and Marshall ().…”

Horizontal eddy energy flux in the world oceans diagnosed from altimetry data

“…The existence of eastward moving eddies may be explained by the fact that they are advected by mean flow23. The zonally averaged zonal EEF changes sign around 44°S (Fig.…”