Urban atmospheric stratification and its dynamics : ABL development above the city of Marseille and in the surroundings

ESCOMPTE 2001 is a field experiment that took place in the south-east of France in order to understand chemical transformation and transport of air pollutants and then to improve numerical models devoted to study and forecasting: http://medias.obs-mip.fr/escompte. In order to build such 3D database, a large set of ground based, onboard and remote data were collected through several measurement techniques. To be used for model validation, such database needs a reliability that can be obtained by checking the data coherence. For this, we had performed a specialized quality control on altitude ozone measurement, including LIDAR, airplanes and radio-sondes instruments, showing a global coherence within an uncertainty below 15%, which fulfils the European guidelines. Such quality control, which was performed on ail chemical and physical measurements, had validated the 3D database and thus ail extracted data shall be compared. As an application to the ABL characterization, several flights were devoted to the study of Marseille urban boundary layer where Wind angular LIDAR, Ozone and aerosol angular LIDAR, wind RADAR profilers and Constant Volume Balloon had made continuous characterization of the urban and sub-urban boundary layers. Thus, such combined results, which give a global overview of the ABL stratification and its dynamic, might also defined some correlations between chemical vertical stratification, especially on ozone and aerosol, and local or global dynamic effects like for example see breeze development.