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Albedo Measurements and Optical Sizing of Single Aerosol Particles



Todd J. Sanford, Daniel Murphy, David S. Thomson, Richard W. Fox


Aerosols play an important role in global climate change by their interactions with incoming solar radiation and outgoing longwave radiation from the planetary surface. The climate effects of aerosols depend on their scattering and absorption properties. This paper describes the development of an instrument that simultaneously measures the scattering and extinction of single aerosol particles. It uses a high-Q cavity to amplify the extinction signal and innovative optics to collect the scattered light. The instrument can distinguish many partially absorbing particles from a few black ones even if the bulk absorption is the same. Optical sizing and single-scattering albedo measurements were made for laboratory-generated particles with diameters from about 300 nanometers to above one micrometer. Using this prototype instrument, changes in albedo for single particles of 20% or greater were detected by measurement of the scattering and extinction. Optical sizing of the individual particles to within 50 nm was accomplished using the ratio of the forward scattered light to the total scattering. Initial measurements of laboratory air showed a mode of highly absorbing particles.
Aerosol Science and Technology


aerosol, ringdown, spectroscopy


Sanford, T. , Murphy, D. , Thomson, D. and Fox, R. (2008), Albedo Measurements and Optical Sizing of Single Aerosol Particles, Aerosol Science and Technology, [online], (Accessed July 19, 2024)


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Created July 30, 2008, Updated October 12, 2021