This study provides a method for quickly calculating the slant and horizontal two-way atmospheric transmittance of a carbon dioxide laser radar operating at 10.591 micrometers . Calculations using this method are performed comparing the two-way transmittance for five atmospheric models: tropical; mid-latitude summer; mid-latitude winter; subarctic summer; and subarctic winter. The two-way transmittance is calculated using an exponential expression for the scattering and absorption attenuation coefficients of the atmospheric molecules and aerosols. The expression, obtained by fitting existing atmospheric attenuation coefficient data, are integrated over the slant range of interest. Results show that the attenuation decreases when the altitude of the laser radar increases for horizontal- and upward-looking line of sight. Results also show that the attenuation increases with increasing altitude and slant range when the laser radar is looking downward toward the earth. The method described can be applied to other available attenuation coefficient data at different laser frequencies.
Robert H. Au, Robert H. Au,
"Comparison of laser radar transmittance for the five atmospheric models", Proc. SPIE 1487, Propagation Engineering: Fourth in a Series, (1 July 1991); doi: 10.1117/12.46569; https://doi.org/10.1117/12.46569