Global distribution and southern hemispheric trends of atmospheric CCl3F

The spatial and temporal variability of the tropospherically inert tracer, trichlorofluoromethane (CCl 3 F), has been simulated using a global atmospheric transport model, incorporating an advective-diffusive transport scheme and known release and photolytic data. The observational data are taken from the Geophysical Monitoring for Climatic Change (GMCC) global network 1,2 , from the Pacific north-west (PNW) USA and South Pole 3 , and from the CSIRO southern hemispheric stations at Cape Grim, Tasmania, and Mawson, Antarctica 4,5 . The resulting global CCl 3 F distribution is shown in Fig. 1. A current CCl 3 F atmospheric lifetime of 75 yr is obtained. The observations suggest that small, residual errors may exist in the CCl 3 F release data.