Program and Agenda

Abstract

SOUTHERN OCEAN CIRCULATION, OCEAN CARBON RESERVOIRS AND ATMOSPHERIC CO2

The Southern Ocean residual overturning circulation is thought to play an important role in the global carbon cycle with a complex interplay of the mechanisms involved. Using a coarse resolution ocean general circulation and biogeochemistry model (MITgcm) we examine an ensemble of idealized perturbations to external forcing and internal physics of the Southern Ocean. The ensemble reveals a striking positive correlation between atmospheric CO2 and Southern Ocean overturning: stronger or northward-shifted westerly winds in the Southern Hemisphere result in increased residual circulation, greater upwelling of carbon-rich deep waters and oceanic outgassing, which increases atmospheric pCO2 by ~20 µatm; weaker or southward-shifted winds have the opposite effect. In an extended suite of simulations we assess the effect of different mesoscale eddy parameterizations and buoyancy forcing. We interpret changes to the carbon inventory in terms of diagnosed saturated, disequilibrium, soft-tissue and carbonate reservoirs. Each varies by O(10–100) PgC and all contribute to the net anomaly in atmospheric CO2. We extend this diagnostic approach to interpret the role of different drivers of the air-sea flux of carbon.

Authors

Lauderdale, J. M., Massachusetts Institute of Technology, USA, jonathan.lauderdale@gmail.com

Naveira Garabato, A. C., University of Southampton, United Kingdom, acng@noc.soton.ac.uk

Oliver, K. I., University of Southampton, United Kingdom, K.Oliver@noc.soton.ac.uk

Follows, M. J., Massachusetts Institute of Technology, USA, mick@mit.edu

Williams, R. G., University of Liverpool, United Kingdom, ric@liv.ac.uk

Details

Oral presentation

Session #:072
Date: 2/25/2014
Time: 15:30
Location: 323 ABC

Presentation is given by student: No