GC13C-0656:
Controls on air-sea CO2 flux in the Southern Ocean east of Australia
Monday, 15 December 2014
Jennifer Ayers, University of Tasmania, Institute for Marine and Antarctic Studies (IMAS), ARC Centre of Excellence for Climate System Science, Hobart, TAS, Australia; Scripps Institution of Oceanography, La Jolla, CA, United States and Peter G Strutton, University of Tasmania, Institute for Marine and Antarctic Studies (IMAS), ARC Centre of Excellence for Climate System Science, Hobart, Australia
Abstract:
The temperate latitudes of the world oceans (~30-50° north and south) are strong sinks for atmospheric CO2 on a mean annual basis. Due to sparse data, the Southern Ocean is the least understood of these CO2 sink regions, with estimates of the annual air-sea CO2 flux varying by as much as 100%, depending upon the calculation method. This work investigates processes regulating air-sea CO2 flux in the Southern Ocean, with a focus on the Pacific sector east of Australia. We quantify the effects of temperature, biological drawdown, and the large-scale general circulation on seawater pCO2 on seasonal and annual timescales, and discuss the balance of these forcings. We expressly consider the impact of the general circulation on the air-sea CO2 flux, which we showed in a previous study to determine the location of the North Pacific carbon sink region. Worldwide, the regions of strong atmospheric CO2 uptake are all located in deep western boundary currents and their extensions, suggesting a larger role for the general circulation in forcing these sinks than is currently acknowledged or understood. Understanding the processes regulating air-sea CO2 flux in the Southern Ocean is critical for predicting how this gas exchange will change in the future.
