Abstract

Ground level atmospheric extinction from 0.5 to 12 μm was determined as a function of date and time of day by a combination of direct visibility measurements and Mie calculations using simultaneously measured particle size distributions. The measurements were made over a three-month period in the Spring of 1987 in the Indian Wells Valley of the Mojave Desert during quiescent weather conditions. Most data were obtained in the late morning and early afternoon, but one set of aerosol size data was obtained for a continuous 60-h period to ascertain diurnal changes. From previous work and a review of the literature an estimate was made of the composition of dust. Results of the Mie computations agree very well with direct visibility measurements. Dust accounted for only 10% of the extinction in the visible.

© 1991 Optical Society of America