CARBON-DIOXIDE AND OXYGEN-ISOTOPE ANOMALIES IN THE MESOSPHERE AND STRATOSPHERE

Isotopic (delta(17)O and delta(18)O) measurements of stratospheric and mesospheric carbon dioxide (CO2) and oxygen (O-2), along with trace s pecies concentrations (N2O, CO, and CO2), were made in samples collect ed from a rocket-borne cryogenic whole air sampler. A large mass-indep endent isotopic anomaly was observed in CO2, which may in part derive from photochemical coupling to ozone (O-3). The data also require an a dditional isotopic fractionation process, which is presently unidentif ied. Mesospheric O-2 isotope ratios differed from those in the troposp here and stratosphere. The cause of this isotopic variation in O-2 is presently unknown. The inability to account for these observations rep resents a fundamental gap in the understanding of the O-2 chemistry in the stratosphere and mesosphere.