VARIABILITY OF AEROSOL OPTICAL-PARAMETERS BY ADVECTIVE PROCESSES

The treatment of atmospheric aerosol in the radiation transfer modelli ng for remote sensing or climate research purposes requires optical ch aracteristics like spectral extinction and phase function or derived p arameters under changing weather conditions. Measurements of optical t hickness and sky brightness (from Sun photometry) carried out in Germa ny give complete data sets to derive columnar aerosol properties (aero sol size distribution, phase function and real part of the optically e quivalent refractive index) by a coupled inversion-transfer program. T hus for these optical data a monitoring program is carried out at seve ral sites in Germany. An air mass classification of the aerosol optica l data can reduce the variability within the classes, gives typical op tical characteristics for different air mass conditions and allows the separation of local and temporal effects by the relation of the data to comparable weather conditions. For the classification, air mass typ es defined by the Berliner Wetterkarte are used. Also, the aerosol opt ical thicknesses and phase functions as the boundary layer extinction properties have distinct characteristics for maritime, continental and aged air masses.