Constraining the Upper Level Vibrational Populations of the N2 Lyman‐Birge‐Hopfield Band System Using GOLD Mission's Dayglow Observations. Issue 9 (22nd September 2022)

• Record Type: Journal Article
• Authors: Aryal, Saurav; Evans, J. Scott; Ajello, J. M.; Solomon, S. C.; Burns, A. W.; Eastes, R. W.; McClintock, W. E.
• Is Part Of: Journal of geophysical research. Volume 127:Issue 9(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-22
• Subjects: LBH -- vibrational population -- remote sensing; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2021JA029869
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: Current and previous thermospheric remote sensing missions use N2 Lyman‐Birge‐Hopfield (LBH) band dayglow emission measurements to retrieve line‐of‐sight thermospheric composition and temperature. The precision of thermospheric composition and temperature retrieved from observations depends on the uncertainty in the relative LBH vibrational populations. In the laboratory, electron impact induced LBH emission measurements have shown that the relative vibrational populations change with gas pressure. However, it is not fully understood how these populations change for dayglow observations where the emissions that contribute to the observations vary with solar illumination and line‐of‐sight geometry. We quantify the relative vibrational populations as a function of solar zenith angle (SZA) and tangent altitude using Global‐scale Observations of Limb and Disk mission's LBH dayglow observations. We find that, while some lower vibrational levels show potential enhancement with increasing pressure (decreasing altitude), in general, they do not change significantly with SZA or tangent altitude for dayglow observations. The vibrational populations can thus be assumed as fixed parameters when retrieving neutral disk temperatures from remotely sensed LBH dayglow observations. Key Points: N2 Lyman‐Birge‐Hopfield (LBH) band vibrational populations are quantified using Global‐scale Observations of Limb and Disk mission's disk and limb dayglow observations Variations in LBH vibrational populations due to solar zenith angle and tangent altitude are insignificant Disk temperature retrievals based on LBH emissions can use same set of vibrational populations