INCREASE OF STRATOSPHERIC CARBON TETRAFLUORIDE (CF4) BASED ON ATMOS OBSERVATIONS FROM SPACE

Stratospheric volume mixing ratio profiles of carbon tetrafluoride, CF 4, obtained with the Atmospheric Trace Molecule Spectroscopy (ATMOS) i nstrument during the ATLAS (Atmospheric Laboratory for Applications an d Science) -3 mission of 1994 are reported. Overall the profiles are n early constant over the altitude range 20 to 50 km, indicative of the very long lifetime of CF4 in the atmosphere. In comparison to the stra tospheric values of CF4 inferred from the ATMOS/Spacelab 3 mission of 1985, the 1994 concentrations are consistent with an exponential incre ase of (1.6 +/- 0.6)%/yr. This increase is discussed with regard to pr evious results and likely sources of CF4 at the ground. Further, it is shown that simultaneous measurements of N2O and CF4 provide a means o f constraining the lower limit of the atmospheric lifetime of CF4 at l east 2,300 years, two sigma.