Model - Measurement Comparison of Coherent Variability in Tropospheric and Stratospheric Ozone

We compare correlations between temporal variations in ozone in the troposphere and lower stratosphere from the TES instrument to the UCI Chemistry-Transport Model and the coupled chemistry version of the NCAR Community Atmosphere Model to examine the contribution of the stratosphere to the variability in tropospheric ozone on monthly timescales. We show that in the models, the spatial pattern of the correlations reflects transport of ozone from the stratosphere into the troposphere, and we compare the seasonal variability of the correlations in the models and in the TES measurements. The results in mid-latitudes are consistent with the variability in stratosphere-troposphere exchange (STE) as diagnosed in the models, but the strongest correlations in both the data and the models are found at Southern high latitudes, where the models show that a large fraction of the ozone in the troposphere has come from the stratosphere, despite relatively small values of the diagnosed STE flux.