ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-6-339-2006 Model simulations and aircraft measurements of vertical, seasonal and latitudinal O<sub>3</sub> and CO distributions over Europe Fischer H. 1 Lawrence M. 1 Gurk Ch. 1 Hoor P. 1 Lelieveld J. 1 Hegglin M. I. 2 Brunner D. 2 Schiller C. 3 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, Zürich, Switzerland FZ Jülich, ICG-1, Jülich, Germany 06 02 2006 6 2 339 348 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/6/339/2006/acp-6-339-2006.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/6/339/2006/acp-6-339-2006.pdf

During a series of 8 measurement campaigns within the SPURT project (2001-2003), vertical profiles of CO and O<sub>3</sub> 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 O<sub>3</sub>, in particular at subtropical and mid-latitudes, while the model overestimates (underestimates) CO (O<sub>3</sub> 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.