1Max Planck Institute for Biogeochemistry, Jena, Germany
2Scripps Institution of Oceanography, University of California, San Diego, USA
3School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
4LOCEAN-IPSL, CNRS, Paris, France
5Institute of Marine Research, Bergen, Norway
6Uni Bjerknes Centre, Bergen, Norway
7Bjerknes Centre for Climate Research, Bergen, Norway
8NOAA Pacific Marine Environmental Laboratory, Seattle, USA
Received: 27 Apr 2012 – Discussion started: 27 Jun 2012
Abstract. A temporally and spatially resolved estimate of the global surface-ocean CO2 partial pressure field and the sea–air CO2 flux is presented, obtained by fitting a simple data-driven diagnostic model of ocean mixed-layer biogeochemistry to surface-ocean CO2 partial pressure data from the SOCAT v1.5 database. Results include seasonal, interannual, and short-term (daily) variations. In most regions, estimated seasonality is well constrained from the data, and compares well to the widely used monthly climatology by Takahashi et al. (2009). Comparison to independent data tentatively supports the slightly higher seasonal variations in our estimates in some areas. We also fitted the diagnostic model to atmospheric CO2 data. The results of this are less robust, but in those areas where atmospheric signals are not strongly influenced by land flux variability, their seasonality is nevertheless consistent with the results based on surface-ocean data. From a comparison with an independent seasonal climatology of surface-ocean nutrient concentration, the diagnostic model is shown to capture relevant surface-ocean biogeochemical processes reasonably well. Estimated interannual variations will be presented and discussed in a companion paper.
Revised: 23 Jan 2013 – Accepted: 29 Jan 2013 – Published: 01 Mar 2013
Rödenbeck, C., Keeling, R. F., Bakker, D. C. E., Metzl, N., Olsen, A., Sabine, C., and Heimann, M.: Global surface-ocean pCO2 and sea–air CO2 flux variability from an observation-driven ocean mixed-layer scheme, Ocean Sci., 9, 193-216, doi:10.5194/os-9-193-2013, 2013.