Variations of stratospheric trace gases measured using a balloon-borne cryogenic sampler

For a better understanding of the cycles of atmospheric trace gases, we have continued to systematically collect air samples in the stratosphere over Japan since 1985, using a balloon-borne cryogenic sampler. The collection of the stratospheric air samples was also made twice over the Scandinavian Peninsula in 1997 and once over Japanese Antarctic station, Syowa in 1998. The air samples collected were analyzed not only for the concentrations of CO2, CH4, N2O and various halocarbons but also for their isotopic ratios. These measurements revealed that, in general, the concentrations of all gas components decreased and their isotopic ratios increased with increasing height, due to influence of atmospheric transport and photochemical destruction in the stratosphere. However, detailed inspection of the results indicated that the observed vertical profiles of the respective components were quantitatively different, depending on location and time. Stratospheric CO2 over Japan showed the secular increase with an average rate of 1.4 ppmv/year for the period 1985–1999.