These 'Fraunhofer' lines are due to the absorption of light of specific frequencies by the gases in the upper atmosphere of the sun. \(1\). Line spectra are produced when electrons move from one ...

187. David M. Slocum, "Molecular line shape analysis at terahertz frequencies using multispectral fitting," Ph.D. dissertation, Dept. Physics and Applied Physics ...

Since many of these gases are trace gases with extremely weak absorption/emission features ... NASA’s Planetary Spectrum Generator is well-suited for the simulation of planetary atmospheric spectra ...

The predicted intensity of this spectrum is so low that a path of the order of 10 km. at atmospheric pressure is required to obtain it in absorption 1,2.

Another notable development is the High Altitude Lidar Observatory (HALO), which utilizes airborne differential absorption ... to measure backscatter spectra of atmospheric water and aerosols ...