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Another possible application of the coupled model is the sensitivity to chemical source gas concentrations. Thus, two simulations were performed with the coupled version of ARPEGE/REPROBUS (on-line mode) starting each at January 1st and using 1995 conditions for SSTs and CO2 concentrations, but one simulation used source gases concentrations of year 1982 (with 2.3 ppbv of total stratospheric chlorine corresponding to pre-ozone hole concentrations) while the second used concentrations of year 1995 (with 3.7 ppbv of total stratospheric chlorine, corresponding to ozone hole conditions). Results (Figure 2) showed no ozone hole for 1982 chemical conditions in contrast to the existence of an ozone hole for 1995 simulation, hence showing a good behaviour of the model in respect to the ozone hole theory.
A good agreement was found with the TOMS total ozone observations for values over Antarctica despite an underestimation of ozone at Southern mid-latitudes (related to the GCM dynamics).
Figure 2 : Southern hemisphere total ozone columns for the on-line coupled ARPEGE/REPROBUS model with different source gas concentration (above) and equivalent observations from the TOMS spectrometer (below).