COMPARISON OF METHODS FOR CALCULATING THE TRANSMISSION FUNCTION FOR ACLOUD-FREE ATMOSPHERE IN THE NEAR-IR AREA OF THE SPECTRUM

The paper studies the error in methods of calculating the transmission function of atmospheric gases using a statistical model of the absorp tion band. A direct implementation of this approach in a very simple p rogram and the well known software package ModTran are considered. The results of comparison of calculations using these methods with direct (linewise) calculations, used as a reference, are given. The absorpti on bands of four gaseous components are studied: H2O, CO2, O-2 and CH4 , in the near-IR area of the spectrum (0.6-2.5 mu m) It is concluded t hat calculations using the ModTran software are highly accurate, so th at it can be used to solve a number of inverse problems of atmospheric optics.