First Measurements of Individual-Particle Single Scattering Albedo: Observations and Potential Impacts on Radiative Forcing

The Aerosol Scattering To Extinction Ratio (ASTER) instrument is the first instrument to measure the single scattering albedo (SSA) of individual aerosol particles. ASTER also sizes particles using a combination of forward, backward, and total scattered light signals. Data on individual-particle single scattering albedos collected at the CALNEX field campaign ground site in Los Angeles, CA during May and June of 2010 will be presented. Externally-mixed modes of absorbing particles were observed throughout the project. The impact of these absorbing particles on the bulk phase-function and radiative transfer will be discussed. We will also present chemical data collected simultaneously with the PALMS single-particle mass spectrometer in an attempt to identify the composition of the highly absorbing particles.