High resolution transmittance curves are presented for the spectral region 320-1400 wave numbers. These spectra are useful as a guide for selecting laser wavelengths for atmospheric propagation studies in this spectral region. In addition, this report provides specific information concerning the attenuation coefficients of 41 CO2 rotational laser lines in the 10.4 micrometer band system (v3 to v1). Charts for predicting the atmospheric attenuation of the CO2 laser lines are provided for each of five climatological model atmospheres and two haze models. The current report extends the work presented in two earlier reports on (1) CO laser attenuation in the 1400-2120/cm−1 (4.72-7. 14 micrometers) region: AFCRL-71-0370 and (2) HF and DF laser attenuation in the 2120-3740/cm (2.67-4.72 micrometers) region: AFCRL-72-0312. This report, when combined with the two previous reports described above, provides synthetic spectra for the entire region from 2.67-31.25 micrometers.

A series of tables and charts is presented from which the atmospheric transmittance between any two points in the terrestrial atmosphere can be determined. This material is based on a set of five atmospheric models ranging from tropical to arctic and two aerosol models. A selected set of laser frequencies has been defined for which monochromatic transmittance values have been given. For low resolution transmittance predcition, a series of charts has been drawn providing the capability for predicting transmittance at a resolution of 20 wave-numbers. Separate sections are included on scattered solar radiation, infrared emission, refractive effects, and attenuation by cloud and fog. This third edition differs from the others in that the low resolution spectral curves for the uniformly mixed gases and in the short wavelength region for water vapor have been revised, providing some overall improvement in accuracy; and more importantly, an appendix has been added providing model data and equivalent sea level path data for the U.S. Standard Atmosphere, 1962.