Introduction of Water-Vapor Broadening Parameters and Their Temperature-Dependent Exponents Into the HITRAN Database: Part I-CO2, N2O, CO, CH4, O2, NH3, and H2S

Y Tan; R V Kochanov; L S Rothman; I E Gordon

doi:10.1029/2019JD030929

Introduction of Water-Vapor Broadening Parameters and Their Temperature-Dependent Exponents Into the HITRAN Database: Part I-CO₂, N₂O, CO, CH₄, O₂, NH₃, and H₂S

J Geophys Res Atmos. 2019 Nov 16;124(21):11580-11594. doi: 10.1029/2019JD030929. Epub 2019 Nov 7.

Authors

Y Tan^{1

2}, R V Kochanov^{1

3}, L S Rothman¹, I E Gordon¹

Affiliations

¹ Atomic and Molecular Physics Division Harvard-Smithsonian Center for Astrophysics Cambridge MA USA.
² Now at Hefei National Laboratory for Physical Sciences at Microscale, iChem Center University of Science and Technology of China Hefei China.
³ Laboratory of Quantum Mechanics of Molecules and Radiative Processes Tomsk State University Tomsk Russia.

Abstract

The amount of water vapor in the terrestrial atmosphere is highly variable both spatially and temporally. In the tropics it sometimes constitutes 4-5% of the atmosphere. At the same time collisional broadening of spectral lines by water vapor is much larger than that by nitrogen and oxygen. Therefore, in order to accurately characterize and model spectra of the atmospheres with significant amounts of water vapor, the line-shape parameters for spectral lines broadened by water vapor are required. In this work, the pressure-broadening parameters (and their temperature-dependent exponents) due to the pressure of water vapor for spectral lines of CO₂, N₂O, CO, CH₄, O₂, NH₃, and H₂S from both experimental and theoretical studies were collected and carefully reviewed. A set of semiempirical models based on these collected data was proposed and then used to estimate water broadening and its temperature dependence for all transitions of selected molecules in the HITRAN2016 database.

Keywords: HITRAN; line broadening; radiative transfer; spectroscopy; water vapor.