Deep Stratosphere-to-Troposphere Transport Revealed by Ground-based Ozone lidar: Three Case Studies

Stratosphere-to-troposphere transport (STT) makes an important contribution to the budget of the tropospheric ozone although the debate about its quantitative significance continues. In terms of the North America region, STT events occur mostly frequently in the midlatitudes, however, they contributes most to the subtropical lower troposphere as expected due to quasi-isentropic descent. Lidar is an ideal instrument to measure the rapid variations of ozone distribution caused by STT because of its high resolution and continuous observation capability. We will present three deep STT cases, all related to the tropopause folds and upper jet stream, measured by the ozone lidar at the University of Alabama in Huntsville in 2010 and 2011. The structures of potential temperature and relative humidity derived from a co-located microwave profiling radiometer (MPR), cross-section of potential vorticity derived from north American mesoscale (NAM) model, ozonesonde profiles, and OMI total ozone observations will be used to identify and analyze the processes.