Vertical profiles of ozone during the EMEFS I experiment in Southern Ontario

Vertical profiles of ozone from the surface to over 15 km altitude were obtained with a combination of free-flying and tethered ozonesondes and differential absorption lidar. During the Eulerian Model Evaluation Field Study (EMEFS I) of July–August 1988, these profiles were compared with the output of a sophisticated regional-scale three-dimensional Eulerian dispersion and chemistry model, the Acid Deposition and Oxidant Model (ADOM). The results show that ADOM predicts the ozone concentration profiles with accuracy only in the lower troposphere and particularly well during simple synoptic situations. In the upper troposphere, the model does not predict the intrusions of ozone from the stratosphere which appear to be extremely important in determining the ozone concentration profile.