Function Descriptions:

• download_data.py: Uses the HAPI toolkit to download absorption line parameters for various gases within a specified spectral range.
• main.py: Uses the HAPI toolkit to plot transmittance and optical thickness under the conditions of the 1976 U.S. Standard Atmosphere.

File Description:

• tape6_1976: Data sourced from MODTRAN. We can get US 1976 atmospheric profiles from this file.

Steps:

• install hapi package from HITRAN
• Run download_data.py.
• Run main.py.