Mass Independent Fractionation in Atmospheric Carbon Monoxide and the Reaction CO + OH

Supun Pathirana

The reaction of CO with OH produces a MIF signal in the remaining CO that is directly related to OH (Röckmann et al. 1998b). OH is the main oxidizing reagent of the atmosphere and the MIF signature contains information about the atmosphere's oxidative state. Indeed, the laboratory data explain the observed size and seasonality of the ¹⁷O anomaly of CO in the atmosphere (Röckmann et al. 1998b; Röckmann et al. 2002). However, the two studies available to date (from network participants IMAU and CCAR) are not in complete agreement. IMAU and CCAR will investigate the anomalous isotope effect in this reaction and its dependence on temperature and pressure in detail. Also collaborate with CCAR to study the production of anomalous CO from ozonolysis of unsaturated compounds. Finally, in collaboration with the LGGE group, we will attempt to reconstruct the ¹⁷O anomaly of CO in the past from ice core air. This could be a unique measure of changes in the oxidative state of the atmosphere in the past.