Principal Investigator: Dr. Molly O'Neil Baringer
Collaborating scientist(s):
Dr. Rana Fine, University of Miami, RSMAS
Dr. Robert Molinari
Mr. Doug Wilson
Objective: Measuring the deep limb of the meridional overturning circulation and assessing the representativeness of heat flux measurements in the center of the subtropical gyre.
Rationale: The meridional overturning circulation in the ocean redistributes and stores heat and carbon input from the atmosphere. During the last ice-age the present-day overturning circulation is thought to have been shut off and replaced by a more vigorous component from the southern ocean (around Anarctica). Long term monitoring of the heat flux in the center of the Atlantic and measuring the components that make up the 'meridional overturning circulation' will help us understand and predict long term trends in the earth's climate system.
Method: Hydrographic and acoustic doppler velocity data were collected during the August 1992 Trident Expedition (Figure 1).
Accomplishment: The deepest, coldest component of the meridional overturning circulation that originates near Antarctica was found to flow northward between 22 and 26 N in the Atlantic (Figure 2).

The heat flux between 22 and 26 N is fairly constant. This suggests that long term monitoring of the heat flux in the Atlantic could be based near 26N where a decade of current meter observations have monitored the total water column east of the Bahamas.

Key reference:
Baringer, M. O'Neil and Rana A. Fine, 1994. Deep Circulation in the Western Subtropical North Atlantic from Trident. The Atlantic Climate Change Program Proceedings from the principal investigators meeting, May 9-11, 1992, University Corporation for Atmospheric Research, Boulder Colorado.

Hacker, P. and E. Firing and W. D. Wilson and R. L. Molinari, 1996. Direct Observations of the Current Structure East of the Bahamas. Geophysical Research Letters, 23, 1127-1130.