Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 5 5 2005 10.5194/acpd-5-9065-2005 http://www.atmos-chem-phys-discuss.net/5/9065/2005/ http://www.atmos-chem-phys-discuss.net/5/9065/2005/acpd-5-9065-2005.html http://www.atmos-chem-phys-discuss.net/5/9065/2005/acpd-5-9065-2005.pdf 9065 9096 2005-09-22 Model simulations and aircraft measurements of vertical, seasonal and latitudinal O₃ and CO distributions over Europe H. Fischer M. Lawrence Ch. Gurk P. Hoor J. Lelieveld M. I. Hegglin D. Brunner C. Schiller Max Planck Institute for Chemistry, Airchemistry Division, P.O. Box 3060, 55020 Mainz, Germany Institute for Atmospheric and Climate Science, Swiss Federal Institute of Technology, Zurich, Switzerland FZ Jülich, ICG-1, Jülich, Germany During a series of 8 measurement campaigns within the SPURT project (2001–2003), vertical profiles of CO and O₃ have been obtained at subtropical, middle and high latitudes over western Europe, covering the troposphere and lowermost stratosphere up to ~14 km altitude during all seasons. The seasonal and latitudinal variation of the measured trace gas profiles are compared to simulations with the chemical transport model MATCH. In the troposphere reasonable agreement between observations and model predictions is achieved for CO and O₃, in particular at subtropical and mid-latitudes, while the model overestimates (underestimates) CO (O₃) in the lowermost stratosphere particularly at high latitudes, indicating too strong simulated bi-directional exchange across the tropopause. By the use of tagged tracers in the model, long-range transport of Asian air masses is identified as the dominant source of CO pollution over Europe in the free troposphere.