Atomic oxygen is a key oxidant for greenhouse gases such as H2O, CH4, and N2O whose
amounts are currently increasing in the stratosphere. Ozone photolysis is a major source of
atomic oxygen generation. We found, for the first time, that the ozone photolysis of 48O3 and
18O16O16O generated a sharp diurnal variation of δ18OOO in the middle stratosphere (37
km), in contrast to the temporal variation of 48O3. The average isotopic enrichment δ18OOO
derived from the Superconducting Submillimeter‐Wave Limb‐Emission Sounder (SMILES) …

Oxygen isotopic signature is a powerful tracer of chemical and physical processes in the
earth's atmosphere. Ozone has the largest oxygen isotopic enrichment in other oxygen-
included species and is a source of oxygen isotopic enrichment. The vertical profile of ozone
isotopic enrichment has been measured; however its variation over time remains
uninvestigated. As ozone isotopic enrichment is generated by the ozone formation reaction
and ozone photolysis, ozone isotopic enrichment is expected to vary over the course of a …