All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 151 15 3
PDF Downloads 24 5 2

Flows Produced by Discrete Sources of Buoyancy

Michael K. DaveyHooke Institute for Atmospheric Research, Department of Atmospheric, Oceanic and Planetary Physics, University of Oxford, Parks Road, Oxford, United Kingdom

Search for other papers by Michael K. Davey in
Current site
Google Scholar
PubMed
Close
and
Peter D. KillworthHooke Institute for Atmospheric Research, Department of Atmospheric, Oceanic and Planetary Physics, University of Oxford, Parks Road, Oxford, United Kingdom

Search for other papers by Peter D. Killworth in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

The response of an ocean with a single active dynamical layer (notionally with an infinitely thick upper layer above it, of slightly less density) to localized buoyancy forcing on a beta-plane is considered. It is shown that three regimes exist. When the forcing is very weak, the response is linear, and consists of a quasi-steady “tube” of fluid stretching westwards from the forcing region, with a front advancing at the long Rossby wave speed, and some transient structure in the vicinity of the forcing. When the amplitude of the forcing is increased, potential vorticity contours are sufficiently deformed to permit instability both in the forced region and to its west. The response becomes a series of shed eddies each of which propagates westwards. The time scale to generate an eddy is proportional to the time taken for a long Rossby wave to propagate across the forced region. Further increase in forcing amplitude yields a completely unsteady response.

Abstract

The response of an ocean with a single active dynamical layer (notionally with an infinitely thick upper layer above it, of slightly less density) to localized buoyancy forcing on a beta-plane is considered. It is shown that three regimes exist. When the forcing is very weak, the response is linear, and consists of a quasi-steady “tube” of fluid stretching westwards from the forcing region, with a front advancing at the long Rossby wave speed, and some transient structure in the vicinity of the forcing. When the amplitude of the forcing is increased, potential vorticity contours are sufficiently deformed to permit instability both in the forced region and to its west. The response becomes a series of shed eddies each of which propagates westwards. The time scale to generate an eddy is proportional to the time taken for a long Rossby wave to propagate across the forced region. Further increase in forcing amplitude yields a completely unsteady response.

Save