Atmospheric Transmittance/Radiance: Computer Code LOWTRAN 6

This report describes a computer code for predicting atmospheric transmittance and the thermal radiation emitted by the atmosphere and earth from 350 to 40,000 per cm at a spectral resolution of 20 per cm. The program is based on the LOWTRAN 5 computer code. Solar/lunar scattered radiation has been added to the code, as well as new spherical refractive geometry subroutines and an improved water vapor continuum model. Other modifications to the code include a wind-dependent maritime aerosol model, a vertical structure aerosol model, a cirrus cloud model, and a rain model. The computer code contains representative (geographical and seasonal) atmospheric models and representative aerosol models with an option to replace with user-derived or measured values. The program can be run in one of three modes, namely, to compute only atmospheric transmittance, to compute atmospheric transmittance and radiance, or to compute atmospheric transmittance, atmospheric radiance, and scattered solar/lunar background radiance for a given slant path geometry. See also supplement, AD-A137 689.