Developed by the University of South Florida, exclusive distribution by Ontar Corporation(Released September 10, 2009) Hitran-PC is a PC computer program that can calculate or model the high-resolution ( < 0.01 cm-1 ) optical transmission spectrum of the atmosphere and of selected gases using primarily the HITRAN Line-by-Line database. Hitran-PC has been developed over the past 20 years, with various levels of improvements and capability, starting with Version 1.0 in 1991 through Version 3.0 in 2000. The latest version, Hitran-PC 4.0, incorporates a major change and advancement in the program and capabilities, and has been developed over the past several years. It now uses the latest 2008 HITRAN Line-by-Line database, but also uses the HITRAN UV and IR Cross Section files, the experimental PNNL IR database, aerosol extinction using the BACKSCAT program, and the water vapor, CO2 and N2 Continuum.
The overall operation of Hitran-PC 4.0 is shown in the following figure. As can be seen, the user can specify the path length, temperature, concentration, line shape (Pressure, Voigt, etc.), and other parameters pertaining to the transmission of the atmosphere. These startup parameters can also be stored in a configuration file for easy use at a later time. The startup parameters are then used along with atmospheric models of pressure/temperature/altitude to model the geometry of the optical transmission path through the gas or atmosphere. Both horizontal and slant path spectral calculations can be made.
The databases and spectral calculations used by Hitran-PC 4.0 consist of:
New features in Hitran-PC 4.0Numerous improvements have been introduced to Hitran-PC 4.0. The most important of them are mentioned in this section.