HITRAN2020: new and improved molecular spectroscopic data for modelling spectra of planetary atmospheres

The HITRAN and HITEMP molecular spectroscopic databases are essential tool for interpreting and modelling planetary spectra (moons and exoplanets, included). For the HITRAN2020 edition [1] (publicly released on www.hitran.org in October, 2021), extended efforts have been made to further increase the database potential for modeling and interpreting spectra of planetary atmospheres.

One of the major improvements towards this goal was the addition (for many HITRAN molecules) of the broadening parameters due to the ambient pressure of He-, H₂- and CO₂ gases. Since hydrogen and helium are the main constituents in the atmospheres of gas giants, and carbon dioxide dominates the atmospheres of many rocky planets, these spectroscopic data are essential for radiative transfer models dedicated to planetary atmospheres.

In addition, spectral and dynamic ranges for many relevant molecules have been extended and new isotopologues added. Moreover six new molecules were added, including CS₂ and SO for (Venus and Io) and GeH₄ (for giant planets).

Finally, substantial update was made to the database of the collision-induced parameters.

The presentation will highlight the most important updates relevant to planetary atmospheres.

[1] Gordon et al, JQSRT 277: 107949 (2022)