Estimating pCO2 from sea surface temperatures in the Atlantic gyres

A simple one-dimensional model, validated with observations from ship of opportunity programs, was run at different locations in the North and South Atlantic gyres to produce seasonal partial pressure of CO2 (pCO2)–sea surface temperature (SST) relationships. The pCO2–SST relationships obtained at different locations in the North Atlantic gyre can be approximated by two regression lines, one from February to July and another from August to January. An algorithm including SST, latitude, longitude and atmospheric pCO2 was constructed for each period. The robustness of these relationships was tested along several transects in the North Atlantic gyre and found to be in good agreement with the observations. The same approach was used in the South Atlantic gyre, but more observations are required in this region. In both gyres, the pCO2–SST relationships are close to 4%/°C, which is higher than the pCO2–SST relationships deduced from a CO2 climatology.