Variability of tropospheric ozone concentrations: comparison of ground-level data with aircraft measurements during the O3 reg campaign (19-21 July 2000)

Abstract The aim of the campaign presented here is to compare data networks' measurements of atmospheric pollutants (mainly tropospheric ozone) with airborne measurements in the atmospheric boundary layer. It is designed to determine whether ozone fields are homogeneous on a regional scale and to show the modulation, on a local scale, of ozone concentrations due to local emissions of anthropogenic and industrial primary pollutants, and/or meteorological thermal processes such as sea/land breeze. The study bears on ozone concentration variability within an anticyclonic air mass on a scale of about 500 km. The contribution of large-scale phenomena in the formation of ozone episodes is shown. Daily maximum ozone values are relatively well representative of tropospheric ozone aircraft measurements. Zooming in on southeastern France establishes that in this area, ozone concentrations arise from multiscale phenomena.