Analysis of the Lowtran transmission functions

Area of Science:

• Atmospheric science
• Computational physics
• Spectroscopy

Background:

• The Lowtran computer code is widely used for modeling atmospheric transmission.
• Accurate molecular absorption functions are crucial for atmospheric modeling.
• Existing empirical functions in Lowtran require analysis and potential updates.

Purpose of the Study:

• To numerically analyze empirical transmission functions for molecular absorption in the Lowtran code.
• To determine absorber and spectral parameters for key atmospheric gases.
• To assess the feasibility of redetermining Lowtran's transmission function parameters.

Main Methods:

• Computerized numerical analysis of empirical transmission functions.
• Adaptation of continuous functions to empirical data.
• Simultaneous determination of absorber and spectral parameters for transmittance data.

Main Results:

• Empirical transmission functions in Lowtran were analyzed using numerical methods.
• Parameters for water (H2O), ozone (O3), and uniformly mixed gases were determined.
• The analysis confirmed that Lowtran parameters can be accurately redetermined numerically.

Conclusions:

• Numerical methods provide an accurate approach to redetermining Lowtran transmission function parameters.
• This methodology facilitates potential code extensions for various absorbers and spectral resolutions.
• Future work can incorporate recent transmittance measurements and expand code applicability.