An empirical estimate of the Southern Ocean air-sea CO 2 flux

• Main Authors: Ben I. Mcneil, Nicolas Metzl, Robert M. Key, Richard J. Matear, Antoine Corbiere
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Southern Ocean; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.144.1996; http://www.gfdl.noaa.gov/reference/bibliography/2007/bim0701.pdf

[1] Despite improvements in our understanding of the Southern Ocean air-sea flux of CO2, discrepancies still exist between a variety of differing ocean/atmosphere methodologies. Here we employ an independent method to estimate the Southern Ocean air-sea flux of CO2 that exploits all available surface ocean measurements for dissolved inorganic carbon (DIC) and total alkalinity (ALK) beyond 1986. The DIC concentrations were normalized to the year 1995 using coinciding CFC measurements in order to account for the anthropogenic CO2 signal. We show that independent of season, surface-normalized DIC and ALK can be empirically predicted to within 8 mmol/kg using standard hydrographic properties. The predictive equations were used in conjunction with World Ocean Atlas (2001) climatologies to give a first estimate of the annual cycle of DIC and ALK in the surface Southern Ocean. These seasonal distributions will be very useful in both validating biogeochemistry in general circulation models and for use in situ biological studies within the Southern Ocean. Using optimal CO2 dissociation constants, we then estimate an annual cycle of pCO2 and associated net air-sea CO2 flux. Including the effects of sea ice, we estimate a