Identifying Ozone Folding Events with Stratosphere-Troposphere Fluxes and Testing against Aura and Ozonesonde Measurements

Chemistry transport modeling (CTM) of the early NASA Aura period (2005-2006) is used to identify tropopause folding (TF) events from O3 profiles and characterize the stratosphere-troposphere exchange (STE) flux of O3 associated with these. We derive the geographically resolved O3 STE flux from the CTM and find that the timing and location of STE flux mostly coincide with those of TF events. We compare the simulated O3 with more than 600 WOUDC O3 sondes per year, focusing on regions with large STE fluxes: looks good, but not great. We also compare CTM simulated O3 with the measurements from the four Aura instruments (i.e., MLS, TES, OMI, and HIRDLS). The CTM simulated anomaly of OMI total column O3 (TCO) matches observation astonishingly well. However, we have latitudinal biases in TCO due to errors in Brewer-Dobson circulation of the 40-layer European Centre (EC) meteorology data. We examine the correlation between OMI TCO anomaly and the TF distribution. As to MLS and TES O3 profiles, we study the possibility of resolving TF events given that MLS data is unavailable for scientific use below 215 hPa and TES vertical resolution in UT/LS region is usually no better than 5 km.