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Atmospheric CO2 has been studied since the beginning of the 19th century. After rough evaluations by Dalton (680 ppmv) and Thenard (391 ppmv), an early systematic series of measurements was carried out by the Swiss chemist Nicolas Théodore de Saussure (1830, working in the vicinity of Geneva. He discovered the daily CO2 cycle, with concentrations between 315 and 540 ppmv at noon, and between 321 and 574 ppmv at night.DOI: 10.1034/j.1600-0889.47.issue1.1.x

We used one year (July 1987 to June 1988) of wind speed measurements made by the microwave radiometer SSM/I to determine the CO2 exchange coefficient between air and sea on a global scale through the Liss and Merlivat relationship. We determined the seasonal variation in every region of the world ocean. It can be as high as a factor of 4 in some areas. An estimate of the accuracy of the retrieved wind speeds showed that this variation is likely to be underestimated. The global averaged CO2 exchange coefficient obtained is 3.34. 10-2 mol m-2 yr-1µatm-1, close to previous estimates. A study of the errors on the retrieved wind speed showed that the exchange coefficient is likely to be underestimated and could be as high as 4 10-2 mol m-2 yr-1µatm-1. We combined these results with various estimates of the annual CO2 partial pressure gradient at the air sea surface and get a net flux absorbed by the ocean. The flux so determined is not meaningful, however, since the covariant variability of the exchange coefficient and of the CO2 partial pressure gradient is not taken into account.DOI: 10.1034/j.1600-0889.1991.00017.x

A theoretical approach to gas transfer by bubbles created by breaking waves at the air-waterinterface is undertaken. Based on a simple model, this study affords a basic understanding of thephysical mechanisms. The behaviour of a single bubble is examined. Similarities and differencesbetween the formulation of gas fluxes across a “flat” air-water interface and through bubbles areshown. The gas flux through bubbles is not strictly proportional to the solubility and to thedifference of concentrations between the bulk of the water and the surface. Nevertheless, fortrace gases, a linear relationship with this difference of concentrations, increasing with solubilityis predicted. Overpressure in the bubbles and dissolution favour invasion into the water andimply a water supersaturation at equilibrium. This supersaturation is more important when thegas solubility is low. The r61e of surfactants is studied and it is found that they can reduce the gasexchange by a factor of 5. The consequences of the model for the transfer velocity are brieflypresented. A better definition of the bubble lifetime, i t . , a better representation of waterdynamics under a breaking wave, is necessary to make more reliable model predictions, mostimportantly for gases with low solubility. Theoretical studies on the bubble source are necessaryin order to avoid, as far as possible, the use of the bubble distribution. DOI: 10.1111/j.1600-0889.1985.tb00075.x