Seasonal variation of tropospheric aerosols by ground based measurements at La Reunion island (20.8° S, 55.5° E)

The seasonal variation of aerosols is studied at La Reunion island by ground based measurements from the marine boundary layer (MBL, about 2000 m above sea level) up to the upper troposphere. La Reunion island is located at 20.8 S and 55.5 E. In this paper, with the help of different indicators, it is shown that the whole troposphere is largely influenced by biomass burning during the dry season (August-November). Measured background concentrations of black carbon and ozone are low (20 ng/m³ and 40 ppbv respectively) whereas during the biomass burning season, they are multiplied by a factor of at least 2 in magnitude