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The moon

, Volume 3, Issue 2, pp 189–213 | Cite as

The directional characteristics of lunar infrared radiation

  • Roman U. Sexl
  • Hannelore Sexl
  • Hanns Stremnitzer
  • Donald G. Burkhard
Article

Abstract

A theory of the directional characteristics of the lunar infrared radiation measured by Saari and Shorthill has been derived. This theory is in excellent agreement with experiment at all angles of observation and at all phase angles. The radiation law used to describe the angular dependence of the infrared radiation emitted by a flat element of the lunar surface is 0.85 cosθ + 0.22 cos2θ, where θ is the angle between the surface normal and the direction of observation. This radiation law is subsequently modified by taking into account lunar surface roughness. We assume a surface covered in part with spherical craters of various depth to diameter ratios as a model for the lunar soil. Re-radiation within the craters has been accounted for. Extensive use is made of group theoretical and invariant tensor methods which enable us to show that most of the details of the radiation pattern do not depend on the detailed nature of the surface features assumed, but only on the average surface slope. A best fit to the Saari-Shorthill data has been obtained by assuming 50% of the lunar surface to be covered with craters with a depth to diameter ratio of 1:3, while the remainder of the surface is essentially flat. The mean deviation between theory and experiment is 4K.

Keywords

Radiation Surface Roughness Excellent Agreement Phase Angle Surface Feature 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© D. Reidel Publishing Company 1971

Authors and Affiliations

  • Roman U. Sexl
    • 1
  • Hannelore Sexl
    • 1
  • Hanns Stremnitzer
    • 1
  • Donald G. Burkhard
    • 1
  1. 1.Department of Physics and AstronomyUniversity of GeorgiaAthensUSA

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