Atmospheric Chemistry and Physics Discussions Interactive comment on “Extrapolating future

Is there really an alternative to the use of coupled chemistry-climate models? Part 2 Gravity wave forcing Gravity wave forcing (GWF) and the cold pole problem is potentially the most serious issue affecting highly temperature dependent processes such as PSC formation. However, it is not as serious an issue for the Arctic as is implied by the authors. The temperature biases of a range of CCMs are shown in Austin et al. (2003) and the largest cold bias is in the upper stratosphere over the southern winter pole. This reaches 30K in models without a GWF scheme. In the lower stratosphere the zonal average temperature does not necessarily give the whole picture as the biases are somewhat smaller ( ˜5K). Here, tropospheric processes and the amplitudes of lower S1073 stratospheric planetary waves could have a larger impact than GWF in producing local temperature variations which determine PSC areas. In the lower stratospheric Arctic, there is certainly no clear indication that zonal average temperatures are improve