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The spatial and temporal variations of atmospheric CO2 at 8–13 km from April 1993 to April 1999 were observed by measuring CO2 mixing ratios in samples collected biweekly from a commercial airliner between Australia and Japan. The CO2 growth rate showed a considerable interannual variation, with a maximum of about 3 ppm yr−1 during late 1997. This variation is related to the El Niño/Southern Oscillation (ENSO) events. A year‐to‐year change related to the ENSO events was also found in the latitudinal distribution pattern of the CO2 annual mean between 30°N and 30°S. The averaged CO2 seasonal cycle in the Northern Hemisphere gradually decayed toward the equator, and a relatively complicated variation with a double seasonal maximum appeared in the Southern Hemisphere. A significant yearly change of the seasonal cycle pattern was observed in the Southern Hemisphere. The impact of a tropical biomass‐burning injection on the upper tropospheric CO2 was estimated on the basis of the CO data from the same airliner observation.

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An automatic measuring system for the partial pressure, pCO 2 , of atmospheric and oceanic carbon dioxide was developed.The system was mounted on a moored buoy for routine observation of maritime meteorology in the East China Sea. CO 2 observations were conducted from 29 June 1997 to 6 January 1998. During the observation period, the atmospheric pCO 2 showed little variation (341 to 365 µatm), whereas pCO 2 in the surface water varied significantly (308 to 408 µatm). In the summer, pCO 2 was higher in the surface water than in the overlying atmosphere, implying that this area was a source for atmospheric CO 2 , though it became a sink after late September. Time series data clearly exhibited significant short-term variations in the oceanic pCO 2 , i.e., sudden variations during the passage of typhoons, and diurnal variations driven by the diurnal variations in the sea-surface temperature under calm conditions. The effects of typhoons on ocean-atmosphere CO 2 exchange at the surface could differ, depending on the relative position of the mooring site with respect to the center of the moving typhoons. These differences result from the different contributions of sea-surface cooling, entrainment, and upwelling. The efflux enhanced by three typhoons accounted for 60% of the efflux of CO 2 in the warm season. It is suggested that typhoons have a significant impact on the carbon cycle in the western subtropical NorthPacific.