Global Observations of Ozone Isotopic Ratios from Mipas Limb Emission Spectra

The observed variations in the isotope ratios often reveal information about the relative strengths of different sources and sinks of the trace gas in question, and about the transport processes which influence its distribution. With the magnitude of the heavy ozone isotope effect known, the isotopes can serve as markers for atmospheric transport and chemical reactions. The enrichment observed in stratospheric CO2 is just one of the possible transfers of an isotopic signature from ozone to another minor constituent. Ozone isotopes of molecular mass 49 and 50 are difficult to measure in the atmosphere since they are present in parts per billion range or below. Measurements of stratospheric ozone [1, 2] and of ozone generated in the laboratory using a variety of techniques consistently find that ozone is enriched relative to O2 in both O and O. The measurements also suggest that a mass-independent process is involved. In this study we present the feasibility of retrieving the different isotopes of ozone and their global distributions and enrichments observed by MIPAS.