STABLE-ISOTOPE ENRICHMENT IN STRATOSPHERIC NITROUS-OXIDE

Nitrous oxide is a greenhouse gas that also plays a role in the cyclin g of stratospheric ozone. Air Samples from the lower stratosphere exhi bit N-15/N-14 and O-18/O-16 enrichment in nitrous oxide, which can be accounted for with a simple model describing an irreversible destructi on process. The observed enrichments are quite large and incompatible with those determined for the main stratospheric nitrous oxide loss pr ocesses of photolysis and reaction with excited atomic oxygen. Thus, a lthough no stratospheric source needs to be invoked, the data indicate that present understanding of stratospheric nitrous oxide chemistry i s incomplete.