5. Atmospheric attenuation calculation codes

5.1 Stripe and line patterns

Based on the theoretical description of physical phenomena, a number of calculation codes have been developed to determine the atmospheric transmission coefficient. Several models can be used.

They are divided into band models with low spectral resolution and line models with high spectral resolution.

The main purpose of the band model is to avoid having to take into account the parameters characterizing the numerous absorption lines when calculating molecular transmittance. There are, however, cases where band parameters have been determined semi-empirically by averaging line parameters (intensity, transition probability, line width, etc.). The band model is a low spectral resolution model and can only be...