Horizon Brightness Revisited: Measurements and a Model of Clear-Sky Radiances

Abstract

Clear daytime skies persistently display a subtle local maximum of radiance near the astronomical horizon. Spectroradiometry and digital image analysis confirm this maximum's reality, and they show that its angular width and elevation vary with solar elevation, azimuth relative to the Sun, and aerosol optical depth. Many existing models of atmospheric scattering do not generate this near-horizon radiance maximum, but a simple second-order scattering model does, and it reproduces many of the maximum's details.

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Document Details

Document Type
Technical Report
Publication Date
Jul 20, 1994
Accession Number
ADA525090

Entities

People

  • Raymond L. Lee Jr.

Organizations

  • United States Naval Academy

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Algorithms
  • Altitude
  • Birds
  • Brightness
  • Digital Images
  • Elevation
  • Forward Scattering
  • Images
  • Line Of Sight
  • Low Altitude
  • Measurement
  • Mie Scattering
  • Observers
  • Optics
  • Radiance
  • Scattering
  • United States Naval Academy

Fields of Study

  • Physics

Readers

  • Atmospheric Remote Sensing.
  • Computational Modeling and Simulation
  • Image Processing and Computer Vision.