Analytic spectral functions for atmospheric transmittance calculations

Area of Science:

• Atmospheric Physics
• Spectroscopy
• Radiative Transfer

Background:

• Accurate solar spectral irradiance data is crucial for climate modeling and remote sensing.
• Previous models often lacked detailed spectral resolution for key atmospheric gases.

Purpose of the Study:

• To develop analytic formulas for spectral absorption coefficients of major atmospheric gases.
• To enable precise engineering calculations of direct and diffuse solar spectral irradiance at the Earth's surface.

Main Methods:

• Derived analytic formulas for transition energies and intensities for H2O and CO2 band systems.
• Developed analytic spectral representations for O3, O2, and CH4 absorption bands.
• Integrated these with extraterrestrial solar irradiance and atmospheric attenuation models.

Main Results:

• Presented comprehensive analytic spectral data for H2O, CO2, O3, O2, and CH4.
• Enabled calculations of direct solar spectral irradiance from 0.35 to 4.5 micrometers.
• Provided a framework for estimating diffuse irradiance.

Conclusions:

• The developed analytic formulas offer a robust method for calculating solar spectral irradiance.
• These findings enhance the accuracy of atmospheric radiative transfer models.
• Facilitates improved engineering applications in solar energy and climate studies.