The Canopy and Aerosol Particles Interaction in Toulouse Urban Layer (CAPITOUL) experiment: first results

The CAPITOUL experiment takes place over the city of Toulouse, France, from february 2004 to march 2005. The objectives are: (i) to study the response of the surface, especially urban energy balance, for a wide range of atmospheric conditions (winter, summer, intermediaite seasons, rainfall, showers, cold, extreme winds, etc...) (ii) to quantify the response of the boundary layer to the city surface forcing, eg, urban breeze, urban (thermodynamical) plumes, impact on fog, and of course continuous observation of the urban heat island. (iii) to measure the transformation of the properties (physical, chemical and radiative) of the urban aerosols, from the emission sites (including turbulent fluxes of aerosols) to the near couintryside (50km away). (iv) to study the dispersion of SF6 in the atmosphere in suburban environment.

Instrumentation includes a 30m tower in city center, for the turbulent fluxes and surface energy balance, 20 stations for UHI, surface temperatures, a scintillometer for turbulent heat measurement, rural stations, including fluxes stations, sites for aerosol measurement, wind profilers, and an aerosol profiler. Altitude measurements are performed by radio-soundings and aircraft.

A presentation of the first results of the campaign will also be conducted, especially the impact of the city on the atmosphere (urban breeze, urban plume).