On the Response of Knollenberg Aerosol Counters.
Abstract
It is known that the response of light-scattering aerosol counters is sensitive to the aerosol refractive index, and that even for a given refractive index there are 'multi-valued' regions where significantly different sizes of particle give the same response. In natural aerosols, the particle size distribution inferred directly from measurements shows a 'knee' followed by a sharp drop. Moreover the position of the knee should depend on the aerosol refractive index. In practice the most obvious feature is a knee near 1 micrometer nominal size on range 0 of the Knollenberg ASAS counter, although further features are present at much poorer resolution on range 1 of the Knollenberg CSAS counter. Here is shown that the position of the knee correlates very well with relative humidity and thus with the refractive index. These 'artificial' features can be turned to advantage in field measurements of natural aerosol since they provide a measure of the refractive index. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1982
- Accession Number
- ADA121427
Entities
People
- P. C. Ashdown
- R. R. Allan
Organizations
- Royal Aircraft Establishment