The Aerosol Spectrometer and Its Application to Nuclear Condensation Studies
- Helmut Weickmann
Published Online: 18 MAR 2013
Copyright 1960 by the American Geophysical Union.
Physics of Precipitation: Proceedings of the Cloud Physics Conference, Woods Hole, Massachusetts, June 3-5, 1959
How to Cite
Goetz, A. and Preining, O. (2013) The Aerosol Spectrometer and Its Application to Nuclear Condensation Studies, in Physics of Precipitation: Proceedings of the Cloud Physics Conference, Woods Hole, Massachusetts, June 3-5, 1959 (ed H. Weickmann), American Geophysical Union, Washington D. C.. doi: 10.1029/GM005p0164
- Published Online: 18 MAR 2013
- Published Print: 1 JAN 1960
Book Series Editors:
- Waldo E. Smith
Print ISBN: 9780875900056
Online ISBN: 9781118668931
- Aerosol spectrometer;
- Artificial aerosol;
- NaC1 aerosols;
- Natural aerosol;
- Nuclear condensation;
- Spiral scale pattern
The aerosol spectrometer (A.S.) separates quantitatively airborne particles in the diameter range 3 μ – 0.03 μ from the atmosphere in the form of a size-spectrum, that is, a continuous band-shaped deposit. The position of a particle thereon is indicative of its ‘Stokes' diameter' while it was airborne, and independent of physical changes incurred after its separation from the suspending air. This size-classified separation results from the exposure of a laminar, continuous air flow to a large centrifugal field (up to 26,000 g), the flow rates vary between 3.3 and 7.4 lit/min. The size (and mass) distribution of the aerosol is derived from the typical variation of the deposit density along the spectrum, either by microscopic count (down to 0.1 μ) or by micro-photometric recording of the light scattered by the particles under reflected dark-field illumination in a special micro-analyzer.
A brief description of the instruments and the mathematical basis of the analytical procedure is presented, also its application to a “model” aerosol of polystyrene latex, consisting of equal-sized particles in various states of agglomeration. From the size definition in terms of the Stokes' diameter, a relationship between the locus of deposition of dry and hydrated hygroscopic nuclei is derived and subsequently supported experimentally for NaCl aerosols.
The A.S. has been applied to the analysis of natural and artificial aerosols in the submicron range. Samples of natural (off-shore and mountain) aerosol spectra are presented; they follow in general the pattern determined by previous authors but show a fine structure which appears to be due to traces of organic matter. The artificial generation and conditioning of NaCl aerosols and the so resulting size distribution is described, particularly the strong effect of the presence of traces of organic vapors (turpentine, pinene) during the hydration and dehydration of the salt nuclei. It is apparent that such traces prevent or delay the equilibrium of the nucleus when the humidity of its gaseous environment is altered.