Measurements of the sky intensity in the solar vertical plane and in the solar almucantar were taken at an arctic location near Barrow, Alaska, a sub-arctic location at Ester Dome, Alaska, and a tropical station at Loiyengalani, Kenya. The data were used to obtain the aerosol scattering phase function for various synoptic conditions and air-mass types. The scattering phase functions were compared to calculated phase functions obtained by assuming various forms of the aerosol size distribution function. Based on the criteria of the best fit of the phase functions the corresonding aerosol size distribution function and the quasi-monochromatic optical depth, numerical estimates were made of the columnar aerosol mass loading. Typical of continental observations, a Junge power-law aerosol size distribution approximates the observed scattering phase function rather well. The observations indicate that the Junge power-law exponent, depends upon air mass type and to a lesser extent on local climatological conditions.

Performed by Geophysical Institute, University of Alaska, Fairbanks. Sponsored by Meteorology Laboratory, National Environmental Research Center. Prepared for U.S. Environmental Protection Agency, Office of Research and Development. "June 1974." "EPA-650/4-75-012." EPA Project Officer: Edwin Flowers. Includes bibliographical references (p. 89-90).