Das Projekt "Luftfahrzeuggestuetzte Messungen von Aerosolen und verbundeen Spurengase" wird vom Umweltbundesamt gefördert und von Max-Planck-Institut für Kernphysik durchgeführt. AAGRA will carry out coordinated balloon-borne measurements of aerosols and related trace gases in the winter polar stratosphere, including measurements of: aerosol size, aerosol number densities, aerosol composition (H2SO4, SO2, HNO3, NH3), condensable gases (H2SO4, HNO3, H2O), optical properties of aerosols (depolarization, index of refraction, shape), aerosol back scattering ratio. The AARGA measurements will, within the framework of SESAME, be closely coordinated with air-borne and ground-based measurements of stratospheric species. In particular, close coordination with ground-based LIDAR measurements will be possible. Furthermore, AARGA measurements will be coordinated with satellite observations, particularly of aerosol properties. Measurements of the properties of aerosols (composition, size, number densities, optical properties) condensed trace gases (H2SO4, HNO3, H2O), and related trace gases (HNO3, HCI), affected by aerosol-catalyzed reactions will be performed using various instruments and methods. A BAMAS (Balloon-borne Mass Spectrometer) - BAMAS-CIMS (Chemical Ionization Mass Spectrometry): Mass spectrometer measurements of trace gases. BAMAS-VACA (Volatile Aerosol Composition Analyses): Mass spectrometer measurements of compounds of volatile aerosols. BAMAS-IOMAS (Ion Mass Spectrometer): Mass spectrometer measurements of ambient ions. Concentration of gaseous H2SO4 can be inferred from ion composition measurements. B. ELHYSA (Etude de I'Hygrometrie Stratospherique et des Aerosols). ELHYSA is a combined water vapour and aerosol instrument. H2O is measured by a frost-point hygrometer. Particle and concentration of aerosols are measured by a laser diode particle counter.