ON THE PHENOMENON OF THE COLORED SUN, ESPECIALLY THE "BLUE" SUN OF SEPTEMBER 1950

Abstract

The phenomenon of the colored sun and moon of September 1950 was explained by utilizing Mie's theory of large particle scattering. The particles were attributed to the smoke generated by large forest fires in Alberta, Canada. The radii and concentration of the particles were calculated to be between 0.5 and 0.8 Mu and between 175 and 127 particles/cu cm, respectively. The total amount of smoke was calculated to be about 4.7 to 6.5 x 10 to the power of 7 particles/sq cm column. A uniform-size and 2 Gaussian distributions were assumed as well as scattering by spherical particles and a refractive index equal to that of water droplets. Calculations of the intensity of the solar spectrum between 3500 and 7000 A, after passage through the smoke lazyer, indicated a pronounced maximum around 4100 and 4600 A in all cases. The physiological impression of such a spectrum was considered to be bluish.

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Document Details

Document Type
Technical Report
Publication Date
Apr 01, 1953
Accession Number
AD0007493

Entities

People

  • Rudolf Penndorf

Organizations

  • Air Force Cambridge Research Laboratories

Tags

Communities of Interest

  • Advanced Electronics
  • Air Platforms
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Distribution Functions
  • Dust Storms
  • Fires
  • Forest Fires
  • Gaussian Distributions
  • Intensity
  • Low Temperature
  • Optics
  • Particle Size
  • Particles
  • Refractive Index
  • Scattering
  • Solar Radiation
  • Solar Spectrum
  • Spectra
  • United States
  • Visible Spectra

Readers

  • Aerosol Science/Aerosol Physics
  • Solar Physics
  • Spectroscopy.