ANALYSIS OF GLOBAL BUDGETS OF HALOCARBONS

It is well known that analysis of global budgets of halocarbons can provide estimates of their atmospheric lifetimes. Furthermore, such analysis may yield information on the interhemispheric mixing rate. The release rates of anthropogenic halocarbons, the average global concentrations, the ratio of hemispherical averages and the rate of change of these ratios are the principal data base for such analysis. These global averaged quantities are derived from a data base of local measurements which may or may not be sufficient to provide global coverage. A generalized analysis allows one to test the consistency of measurements and the global average theory. The sensitivity of derived results for atmospheric lifetimes is shown and the technique for analysis is illustrated with applications to CFCl3 and CH3CCl3. The lifetime analysis for CFCl3 shows considerable sensitivity to uncertainties and variabilities in the data. Nevertheless these data are shown to be consistent with an average interhemispheric transport time of 1-2 years. The data for methylchloroform are shown to be consistent with an atmospheric lifetime of 11.3 years. © 1978.