AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Polar Nephelometer for the Measurement of the Particle Asymmetry Parameter
Paul Kebabian, TIMOTHY ONASCH, Joda Wormhoudt, Andrew Freedman, Aerodyne Research, Inc.
Abstract Number: 141 Working Group: Instrumentation and Methods
Abstract Radiative transfer models use the particle asymmetry parameter, g, as a measure of scattering angle because it is far more computationally efficient than including the entire scattering phase function. We present a proof-of-principle demonstration of an apparatus capable of directly measuring the aerosol scattering phase function and aerosol asymmetry parameter without the need for calibration or adjustment of data. The measurement technique utilizes a technique which allows for the collection of scattered light at all angles simultaneously and thus offers the potential for more rapid acquisition of scattering data from ambient polydisperse aerosols compared to polar nephelometers which measure scattered light from one angle at a time. Measurements of monodisperse polystyrene latex and polydisperse ammonium sulfate particles indicate that the measured value of the asymmetry parameter is within ±0.03 of that calculated using Mie theory.