Accession Number : AD0915878

Title :   Atmospheric Propagation in the Middle-Infrared and at 8-14 Micrometers.

Descriptive Note : Final rept.,

Corporate Author : TECHNOLOGY SERVICE CORP SANTA MONICA CA

Personal Author(s) : Stacey, J. ; Arnold, J.

Report Date : 28 SEP 1973

Pagination or Media Count : 128

Abstract : This study considers the problems of propagation through the lower troposphere in the middle-infrared and in the 8 to 14 micrometer regions of the spectrum. The atmospheric constituents that scatter and absorb energy at these wavelengths are identified and the losses are calculated for several air-to-ground transmission paths. Examples of the atmospheric transmission losses are calculated for several passive sensor bandpasses and for a radar at 10.59 micrometers. In these examples, the atmospheric constituents that contribute to the total propagation loss over the sensor bandpass are individually identified and the accumulated losses are separately reported as a function of slant range. The performance for active and passive sensors is calculated and plotted for a host of weather conditions. Variations in rain rates, fog densities, and haze visibilities are introduced to demonstrate the relative degradation to the S/N for the sensor system. Aircraft measurements of atmospheric constituents are examined to determine if an empirical relationship exists between haze visibility and slant-path transmittance. Empirical expressions for haze attenuation are derived for selected wavelengths in the middle-infrared region and at 10.59 micrometers. Attenuation from common chemical smokes is estimated.

Descriptors :   *CARBON DIOXIDE LASERS), (*ATMOSPHERES, LIGHT TRANSMISSION), (*OPTICAL RADAR, (*INFRARED DETECTORS, AIRBORNE), (*MOLECULAR SPECTROSCOPY, ABSORPTION SPECTRA), AIR TO SURFACE, SLANT RANGE, FAR INFRARED RADIATION, ATTENUATION, LOSSES, RAIN, FOG, HAZE, SIGNAL TO NOISE RATIO, LASER BEAMS, DIGITAL COMPUTERS, COMPUTER PROGRAMS, TRANSPARENCE, BAND SPECTRA, CARBON DIOXIDE, WATER VAPOR, TROPOSPHERE, NITROGEN OXIDES, INFRARED PULSES, ENERGY, QUANTUM EFFICIENCY.

Subject Categories : Atmospheric Physics
      Lasers and Masers
      Infrared Detection and Detectors
      Active & Passive Radar Detection & Equipment
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE