Skip to main content
padlock icon - secure page this page is secure

Free Content The effect of topography on the steady-state wind and buoyancy-driven Subtropical Gyre

Download Article:
 Download
(PDF 4,265.2 kb)
 
This paper studies the impact of topography and increased vertical resolution on steady-state wind and buoyancy-driven circulation in the Subtropical Gyre. Buoyancy driving is represented by mass exchange across the interface separating layers of constant density. The mass exchange in turn is parameterized in terms of the departure of a layer thickness from a reference value. A 2-layer ocean model is developed that incorporates topography that depends on the meridional co-ordinate, and the problem reduces to solving a first order partial differential equation governing the upper layer inverse planetary potential vorticity. Two distinct families of characteristic curves are required to span the entire subtropical gyre; an "interior family" emanating from the eastern boundary and a family lying in the northwestern corner that begin and end along the oceanic edge of the western boundary current. It is demonstrated that when the ocean shoals (deepens) poleward, the area of the recirculating gyre in the northwestern corner decreases (increases) in response to the increased (decreased) phase speed of long baroclinic Rossby waves. The model is applied to the subtropical North Atlantic gyre, using climatological Ekman pumping, zonally averaged topography and a realistic representation of the eastern boundary and the solutions are qualitatively compared with these from a general ocean circulation model. To address how increased vertical resolution modifies the recirculating gyre structure, solutions are calculated for a 3-layer flat bottom ocean model. The circulation in the top and bottom layers of this model are qualitatively similar to those in the 2-layer model. In the middle layer there is a recirculating anticyclonic gyre of extent similar to that in the 2-layer model. Outside this gyre is a second anticyclonic gyre of larger horizontal extent. The double-gyre structure in the middle layer is associated with the existence of two separatrices subdividing the layers into three regions. These curves separate two distinct families of characteristic curves each associated with the upper and lower layer inverse planetary potential vorticity equations.

15 References.

No Supplementary Data.
No Article Media
No Metrics

Document Type: Research Article

Publication date: May 1, 2004

More about this publication?
  • The Journal of Marine Research, one of the oldest journals in American marine science, publishes peer-reviewed research articles covering a broad array of topics in physical, biological and chemical oceanography. Articles that deal with processes, as well as those that report significant observations, are welcome. Biological studies involving coupling between ecological and physical processes are preferred over those that report systematics. The editors strive always to serve authors and readers in the academic oceanographic community by publishing papers vital to the marine research in the long and rich tradition of the Sears Foundation for Marine Research. We welcome you to the Journal of Marine Research.
  • Editorial Board
  • Information for Authors
  • Subscribe to this Title
  • Purchase The Sea
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more