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Jian Wang Brookhaven National Laboratory Atmospheric Sciences Division Bldg. 815E, 75 Rutherford Drive Upton, NY 11973-5000 Tel: 631-344-7920 Fax: 631-344-2887 email: jian@bnl.gov Brookhaven National Laboratory (BNL) proposes to develop two novel instruments for aircraft-based measurements of aerosol size distribution, hygroscopicity, and chemical composition. The proposed developments support field studies using aircraft as a primary measurement platform. The first instrument, referred to as an Aerosol Mobility Size Spectrometer (AMSS), separates charged aerosol particles into different flow streams according to their sizes. The separated particles are grown into supermicron droplets in a supersaturated environment and are, subsequently, detected by an imaging system. The imaging system records mobility-dependent particle positions and their numbers, which are then used to derive particle size distribution spectra. By eliminating the necessity to scan over a range of particle sizes, AMSS significantly improves measurement speed and counting statistics. The second proposed instrument, referred to as an Aerosol Hygroscopicity and Volatility Spectrometer (AHVS), first selects monodisperse dry aerosol through a differential mobility analyzer. The monodispersed aerosol is then directed to either a humidifier (hygroscopicity measurements) or a thermal denuder (volatility measurements). The size distributions of processed aerosols, which are measured by an AMSS downstream, are used to derive aerosol hygroscopicity and volatility. The hygroscopicity and volatility measurements will also be combined to derive size-resolved aerosol chemical compositions and mixing states. Keywords: Aerosol size distribution, hygroscopicity, volatility, chemical composition, aircraft-based measurements [back to ASP ST Membership] |