Mesoscale analysis of transport across the subtropical tropopause

An airborne ozone lidar has been operated on March 26 and 27, 1999 in order to document the ozone distribution near the subtropical jet (STJ) in the 5 degreesW-15 degreesW longitude band which corresponds to an area where the STJ accelerates and interacts strongly with mid-latitude cyclones. The two main features observed are a tropopause fold in the region where the STJ accelerates and an intrusion of subtropical tropospheric air into the mid-latitude lower stratosphere. A mesoscale meteorological model is applied with high vertical resolution in order to study the strong layering in the upper troposphere and lower stratosphere.