Stratosphere-Troposphere Exchange Over Houston

Ozone-rich stratospheric air can enter the troposphere through tropopause folds. These folds occur in a post-frontal environment, and these stratosphere-troposphere exchange (STE) events can lead to an enhancement of tropospheric ozone. Ozonesonde data from Houston, Texas during the period July 2004 to May 2009 are examined to assess the presence of STE during each ozonesonde-documented frontal episode. Ozonesonde derived ozone mixing ratio and relative humidity were used to detect potential layers of STE from over 300 frontal passage-related profiles. These layers were then further examined with Hysplit regression modeling, potential vorticity profiles, and laminar labeling analysis to further investigate STE signatures. Weekly average surface Beryllium-7 (7Be) was examined the week of each frontal episode, and then compared to the 20-year average. Statistical linear modeling was also applied to this data set, yielding statistical correlations between an STE environment and various meteorological factors, as well as statistical correlations between a non-STE environment and the same meteorological factors.