Choosing meteorological variables to be assimilated into off-line CTM driven by GCM for ozone reanalysis

We investigate the impact of changing meteorological variables obtained from the objective analysis to be nudged into the General Circulation Model (GCM), in order to provide realistic ozone simulation with the Chemical Transport Model (CTM) driven by the nudged GCM. Two experiments have been performed, one nudges only horizontal wind, the second does temperature additionally. Nudging horizontal wind reproduces the zonal mean ozone field well because of the realistic meridional transport. Meanwhile, nudging temperature produces spurious heating especially near the tropopause owing to cold bias of the GCM, and makes meridional circulation stronger in the lower stratosphere and weaker in the troposphere. The deformed circulation results in degradation of the ozone field. On the other hand, chemical processes require more realistic temperature, so that the nudging temperature may be favorable. Especially, depth of Antarctic ozone hole is sensitive to the change in nudging variables through the polar stratospheric cloud occurrence.