ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-11-7547-2011 High resolution modelling of aerosol dispersion regimes during the CAPITOUL field experiment: from regional to local scale interactions Aouizerats B. 1 Tulet P. 1 2 Pigeon G. 1 Masson V. 1 Gomes L. 1 CNRM-GAME, URA1357, 42 av G. Coriolis, 31057 Toulouse, France LACy, Université de La Réunion, 15 av René Cassin, 97715 Saint-Denis, France 01 08 2011 11 15 7547 7560 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/11/7547/2011/acp-11-7547-2011.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/11/7547/2011/acp-11-7547-2011.pdf

High resolution simulation of complex aerosol particle evolution and gaseous chemistry over an atmospheric urban area is of great interest for understanding air quality and processes. In this context, the CAPITOUL (Canopy and Aerosol Particle Interactions in the Toulouse Urban Layer) field experiment aims at a better understanding of the interactions between the urban dynamics and the aerosol plumes. During a two-day Intensive Observational Period, a numerical model experiment was set up to reproduce the spatial distribution of specific particle pollutants, from the regional scales and the interactions between different cities, to the local scales with specific turbulent structures. Observations show that local dynamics depends on the day-regime, and may lead to different mesoscale dynamical structures. This study focuses on reproducing these fine scale dynamical structures, and investigate the impact on the aerosol plume dispersion. The 500-m resolution simulation manages to reproduce convective rolls at local scale, which concentrate most of the aerosol particles and can locally affect the pollutant dispersion and air quality.

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