Observing Methods for the Meridional Overturning Circulation and Meridional Heat Transport in the South Atlantic

PIs: Renellys Perez, Silvia Garzoli, and Chris Meinen
External PIs: Ricardo Matano

This is a project to analyze multiple models and determine the optimal design and location for a zonal trans-basin array that will characterize the variability of the Meridional Overturning Circulation (MOC) and meridional heat transport (MHT) in the South Atlantic. Such sustained observations in the South Atlantic are needed to assess and improve long-term climate predictions. The ability to reconstruct the MOC and MHT within the models using geostrophic velocity measurement techniques is evaluated at various latitudes in the South Atlantic. Across the basin, geopotential height anomaly profiles and geostrophic velocities are either obtained directly from the model temperature and salinity profiles, or inferred from current and pressure recording inverted echo sounders deployed within the model. Model sampling experiments suggest that a geostrophic-type array performs best at higher latitudes (nominally 30S-35S). This modeling work will continue and contribute to the design of a realistic South Atlantic array that incorporates two pilot arrays deployed along 34.5S.

Figure. Map of a) Parallel Ocean Climate Model (POCM) and b) OGCM For the Earth Simulator (OFES) mean meridional velocity at 200m depth. Lines indicate the five latitudes tested for a potential South Atlantic array: 15S, 20S, 25S, 30S and 34.5S. Black contours indicate the 100m and 1500m isobaths. Figure reproduced from Perez et al. (2010).


Perez, R. C., S. L. Garzoli, C. S. Meinen, R. P. Matano, 2011. Geostrophic Velocity Measurement Techniques for the Meridional Overturning Circulation and Meridional Heat Transport in the South Atlantic. Journal of Atmospheric and Oceanic Technology, J. Atmos. Ocean. Tech., 28, 1504-1521.