HR: 1340h
AN: A23B-0787    [Abstracts]
TI: On the Role of Pacific-Indian Basin Upwelling in Maintaining the Global Meridional Overturning Circulation
AU: Emanuel, K A
EM: emanuel@texmex.mit.edu
AF: Massachusetts Insitute of Technology, 77 Massachusetts Avenue Room 54-1620, Cambridge, MA 02139 United States
AU: * Korty, R L
EM: korty@mit.edu
AF: Massachusetts Insitute of Technology, 77 Massachusetts Avenue Room 54-1620, Cambridge, MA 02139 United States
AU: Scott, J R
EM: jscott@mit.edu
AF: Massachusetts Insitute of Technology, 77 Massachusetts Avenue Room 54-1620, Cambridge, MA 02139 United States
AB: An idealized, ocean only general circulation model is used to investigate the importance of diapycnal mixing in different basins to the global meridional overturning circulations. We find that when mixing is concentrated in the tropical Pacific-Indian basin, a global circulation can be maintained with sinking in the North Atlantic and Antarctic and upwelling throughout the Pacific and Indian Oceans. The magnitude of the northward heat flux in the North Atlantic is similar regardless of whether mixing is spread evenly across the globe or concentrated in the tropical Pacific. The northward heat flux in the South Atlantic, however, is close to that observed only when mixing is concentrated in the tropical Pacific. When diapycnal mixing is instead concentrated in the tropical Atlantic, a single-hemisphere, single-basin cell in the North Atlantic is maintained, but most of the deep water formed is upwelled in the Atlantic leaving the Pacific largely quiescent. Thus a reasonably strong heat flux in the North Atlantic is maintained, but the heat flux reverses sign in the South Atlantic and nearly vanishes in the Pacific. In summary, the intensity of the overturning circulation in the North Atlantic increases with the intensity of mixing in either the Atlantic or the Pacific, but the connections between basins are maintained only when mixing is confined to the tropical Pacific or spread uniformly over the globe.
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 3344 Paleoclimatology
DE: 4532 General circulation
DE: 1620 Climate dynamics (3309)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting