A221-0012
Evaluating the line-shape parameters of air- and self- broadened CO2 lines toward a sub-percent accuracy level in atmospheric retrievals
Wednesday, 16 December 2020
Poster
Robab Hashemi1, Iouli Gordon2, Ha Tran3, Roman V Kochanov4, Ekaterina Karlovets2, Yan Tan5, Julien Lamouroux6, Ngoc Hoa NGO7 and Laurence S Rothman8, (1)Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, United States, (2)Harvard-Smithsonian Center for Astrophysics, Atomic and Molecular Physics, Cambridge, MA, United States, (3)Laboratoire de Météorologie Dynamique, IPSL, CNRS, Sorbonne Université, Ecole normale superieure,PSL Research University, Ecole Polytechnique, F-75005, Paris, France, (4)Tomsk State University, Laboratory of Quantum Mechanics of Molecules and Radiative Processes, Tomsk, Russia, (5)Hefei University of Science and Technology of China, Hefei, China, (6)Independent researcher, Paris, France, (7)Hanoi National University of Education,, Faculty of Physics, Cau Giay, Vietnam, (8)Smithsonian Astrophysical Observatory, Atomic and Molecular Physics, Cambridge, MA, United States
Abstract:
This work describes the upcoming update to the HITRAN ]database [1] with respect to the line-shape parameters for carbon dioxide broadened by air and carbon dioxide for atmospheric applications. We present a revised set of line-shape parameters of CO
2, including half widths and shifts and their temperature dependence parameters. Also, thanks to the relational structure of the HITRAN database, we added a full set of the parameters associated with the speed-dependent Voigt line-shape. Furthermore, a semi-empirical approach [2] educated by the most reliable experimental data was used to calculate the line shifts of air- and self- broadened CO
2 lines. In general, systematic method was developed to generate line-shape parameters based on either existing measured data or the theoretical calculation adjusted to carefully selected measurements. The full and the first-order line-mixing parameters have been calculated using the updated line-shape parameters by the program developed by Lamouroux et al. [3]. The first-order line-mixing parameters will be provided for every line of CO
2 in HITRAN.
In order to verify these new data, different sets of laboratory spectra were used to compare with the absorption coefficient calculated by the line-mixing program and HITRAN Application Programming Interface (HAPI) [4] which implements necessary functionality. Significant improvements were achieved for the regions examined in this study, and compared to HITRAN2016, which will be advantageous for the CO2 retrievals for OCO-2, ACE, and GOSAT missions, for example. In particular, near 2.06 µm, the residuals were obtained at the desired level of 0.3 % accuracy when using the Voigt profile with full line-mixing.
Our results are involved in the general enhancement of the HITRAN spectroscopic database, in its accuracy, consistency, and completeness. The new data is proposed for the HITRAN2020 edition and can be tested using HAPI and the line-mixing package available in https:// hitran.org/supplementary/.
[1] Gordon et al, JQSRT 203 (2017) 3-69.
[2] Hartmann, JQSRT 110 (2009) 2019-2026.
[3] Lamouroux et al, JQSRT 151 (2015) 88-96.
[4] Kochanov et al, JQSRT 177 (2016) 15-30.
