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  • Author or Editor: J. M. Rosen x
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J. M. Rosen and D. J. Hofmann


A condensation nuclei (CN) counter has been developed for balloonborne use at ambient pressures in the troposphere and stratosphere. The instrument employs a thermal gradient diffusion cloud chamber to produce particle growth and a photoelectric particle counter for detection. After extensive laboratory tests, the instrument was successfully flown on several balloon soundings over Laramie. The results show a roughly constant mixing ratio in the stratosphere with a CN concentration of about 20 cm−3 at 15 km. The vertical profile of CN in the troposphere displayed concentration fluctuations ranging between 200 and 2000 cm−3 with a definite maximum in the mixing ratio just below the tropopause.

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Richard D. Cadle, Gerhard Langer, J. B. Haberl, A. Hogan, James M. Rosen, William A. Sedlacek, and J. Wegrzyn


Laboratory comparisons have been made of aerosol concentrations indicated by four different types of condensation nucleus counters. Three of these counters, the Langer, Rosen, and General Electric SANDS instruments have been used to measure Aitken nuclei concentrations in the upper troposphere and the stratosphere, and the fourth, a Pollak counter, had been carefully calibrated to serve as a standard. Except for the smallest particles employed, quite good agreement was experienced among the Rosen, SANDS and Pollak counters, and the tests served to calibrate the Langer instrument.

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