Accession Number : AD0783484

Title :   Light Refraction by Mean Temperature Gradients in the Near-Earth Atmosphere.

Descriptive Note : Final rept.,

Corporate Author : BALLISTIC RESEARCH LABS ABERDEEN PROVING GROUND MD

Personal Author(s) : Wesely,Marvin L. ; Stearns,Charles R.

Report Date : JUN 1974

Pagination or Media Count : 42

Abstract : Visible light ray paths in the atmospheric surface layer are numerically computed by division of 500- to 5000-m ranges into small intervals so that the ray path height and thus the refractive index gradient is nearly constant for each step. Meteorological conditions are varied by using different combinations of sensible heat fluxes, surface stresses, and surface roughness. Although the effect of water vapor gradients can be substantial, their effect is not included here. The results are confined to heights less than five m because of the restrictive values chosen for the ratio of the eddy diffusivity of heat to that of momentum. Mirages hide lower portions of images and the minimum observable height varies approximately in inverse proportion to the observer height. (Modified author abstract)

Descriptors :   *LASER BEAMS, *REFRACTIVE INDEX, COHERENT RADIATION, RAY TRACING, CURVE FITTING, DISTORTION, COMPUTATIONS, COMPUTER PROGRAMS

Subject Categories : Atmospheric Physics
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE