Systematic collections of stratospheric air samples have been conducted over Japan since 1985 using a balloon-borne cryogenic sampler. The collection of stratospheric air samples was also carried out twice over Scandinavia and once over Antarctica. Vertical profiles of CO2 concentration thus obtained over these locations were quite similar to each other; CO2 concentration decreased with increasing altitude in the lower stratosphere and reached an almost constant value in the mid-stratosphere. δ13C of stratospheric CO2 observed over these locations enriched with increasing altitude. A negative correlation between δ13C and CO2 concentration with Δδ13C/ ΔCO2 of -0.02‰ ppmv-1 was found in the lower stratosphere. Although CO2 concentration was almost constant in the mid-stratosphere, the δ13C enrichment was observed in succession, δ18O of stratospheric CO2 also enriched with increasing altitude. The enrichment was significant; δ18O was almost 0‰ at the tropopause and reached a maximum value of about 11‰ at a layer with N2O concentration of about 10 ppbv. A compact relation between δ18O and N2O concentration was consistently observed for these locations. Stratosperic CO2 over Japan showed a secular increase with an average rate of 1.4 ppmv yr-1 for the period 1985-2000. The secular increase was not constant with time, and temporal stagnation of the CO2 increase was observed in 1997.
|Number of pages
|Tellus, Series B: Chemical and Physical Meteorology
|Published - 2003 Apr