Abstract
Concentrations of cloud condensation nuclei in the atmosphere were measured at Rolla, Missouri, near ground level. A total of 432 spectra were measured over a 10-month period. The average concentration (N) of nuclei active at supersaturation, S, followed the two-stage power low:
N−3S0.643S
N7−3S3.85S
No consistent seasonal or diurnal pattern was observed. Possible implications for fogs and stratus clouds and for nuclei chemical composition are discussed.
