Analysis of Water Vapor Absorption Lines in Modern Spectroscopic Databases in the 16 700–17 000 cm−1 Region

Abstract

The validation of H₂O absorption lines parameters in the modern spectroscopic databases such as HITRAN2016, HITRAN2020, GEISA2020, and W2020 is carried out in the visible region 16 700–17 000 cm⁻¹. The H₂O transmission spectra are simulated with the spectroscopic databases and compared with laboratory spectra of pure water vapor and H₂O–N₂ mixture (P = 1 atm) recorded using a Fourier spectrometer with light-emitting diodes of high luminance. The parameters of 65 H₂O absorption lines from HITRAN2020 database are corrected on the basis of the measurements. The positions of 32 lines, intensities of 51 lines, and self-broadening coefficients of 10 lines are improved. The ratio of the HITRAN2020 broadening coefficients to the experimental values is close to 1, whereas the air pressure-induced line shift coefficients in the spectroscopic databases are, on average, two times higher than the experimental values, and therefore, our previously obtained experimental values of N₂ pressure-induced line shift coefficients are used to simulate the transmission spectra of the H₂O–N₂ mixture. The difference of the experimental spectra from the spectra calculated with HITRAN2016, HITRAN2020, GEISA2020, W2020, and corrected HITRAN2020cor is estimated by the root-mean-square deviations RMS = 1.49 × 10^–4, 1.64 × 10^–4, 3.96 × 10^–4, 3.49 × 10^–4, and 1.26 × 10^–4, respectively, in the case of pure water vapor and 1.15 × 10^–4, 1.1 × 10^–4, 2.23 × 10^–4, 2.28 × 10^–4, and 0.86 × 10^–4 in the case of H₂O–N₂ mixture.