Abstract |
Visibilities were measured at Cedar Mountain, Utah during 10 non-consecutive periods of 4 weeks each between November 1976 and October 1978. Annual means of 128 kilometers from the photographic method and of 160 kilometers from telephotometry with a phototopic filter were derived. Except for the unusually clear period from November 1976 to January 1977 the average visual range had remained unaltered within one sigma standard deviation for seasonally comparable periods. No effects of local or regional power plants on visibility could be delineated. Visibilities varied by as much as 3.5 times during individual observation periods in response to changes in mesometeorology. In support of the visibility study, aerosols were collected on filters for size, shape, and elemental composition analyses. X-ray fluorescence, induced by alpha-particles for bulk analysis, and by electrons for single-particle analysis, was used to determine the elemental composition of the aerosol. No statistically significant correlation between visibility and aerosol elemental composition could be established. |