Aerosols can be characterized according to their size, their optical properties or their physico-chemical behaviour. All these properties can be used for source appointments and climate impact analysis. For airborne applications the size distribution from 5 to 350 nm is measured with a fast differential mobility particle spectrometer, from 300 nm to 20 μm using an optical particle spectrometer. Faster response within 1 sec is also possible without detailed particle sizing. Concerning the optical properties the two main parameters are scattering and absorption, both wavelength dependent. Airborne instrumentation for spectral absorption from 370 to 950 nm and scattering coefficients from 450 to 700 nm is used together with the size distribution for characterisation of aerosol sources and for comparison with radiation transfer models. Also the combination of optical properties, size distributions and their dependence on meteorological parameters allows a characterisation of the chemical behaviour which otherwise would require more low time resolution sampling and chemical analysis.
Contacts: Wolfgang Junkermann