Abstract. This study evaluates simulated vertical ozone profiles produced in the
framework of the third phase of the Air Quality Model Evaluation
International Initiative (AQMEII3) against ozonesonde observations in North
America for the year 2010. Four research groups from the United States (US)
and Europe have provided modeled ozone vertical profiles to conduct this
analysis. Because some of the modeling systems differ in their meteorological
drivers, wind speed and temperature are also included in the analysis. In
addition to the seasonal ozone profile evaluation for 2010, we also analyze
chemically inert tracers designed to track the influence of lateral boundary
conditions on simulated ozone profiles within the modeling domain. Finally,
cases of stratospheric ozone intrusions during May–June 2010 are investigated
by analyzing ozonesonde measurements and the corresponding model simulations
at Intercontinental Chemical Transport Experiment Ozonesonde Network Study
(IONS) experiment sites in the western United States. The evaluation of the
seasonal ozone profiles reveals that, at a majority of the stations, ozone
mixing ratios are underestimated in the 1–6 km range. The seasonal change
noted in the errors follows the one seen in the variance of ozone mixing
ratios, with the majority of the models exhibiting less variability than the
observations. The analysis of chemically inert tracers highlights the
importance of lateral boundary conditions up to 250 hPa for the
lower-tropospheric ozone mixing ratios (0–2 km). Finally, for the stratospheric
intrusions, the models are generally able to reproduce the location and
timing of most intrusions but underestimate the magnitude of the maximum
mixing ratios in the 2–6 km range and overestimate ozone up to the first kilometer
possibly due to marine air influences that are not accurately described by
the models. The choice of meteorological driver appears to be a greater
predictor of model skill in this altitude range than the choice of air
quality model.