Traveling planetary wave activity from mesopause region airglow temperatures determined by the Network for the Detection of Mesospheric Change (NDMC)

Reisin, Esteban Rodolfo; Scheer, J.; Dyrland, M. E.; Sigernes, F.; Deehr, C. S.; Schmidt, Carsten; Höppner, Kathrin; Bittner, Michael; Аммосов, Петр; Gavrilyeva, Galina; Stegman, J.; Perminov, V. I.; Semenov, A. I.; Knieling, Peter; Koppmann, R.; Shiokawa, K.; Lowe, R. P.; López-González, M. J.; Rodríguez‐López, C.; Zhao, Yucheng; Taylor, Mike; Buriti, R. A.; Espy, P. J.; French, John; Eichmann, K. ­U.; Burrows, J. P.; Savigny, Christian von

doi:10.1016/j.jastp.2014.07.002

Cited by 36 publications

(16 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3). Section 4 discusses the differences in the derived OH level populations for the Einstein-A coefficients of Mies (1974), Langhoff et al (1986), Turnbull and Lowe (1989), van der Loo and Groenenboom (2008), Rothman et al (2013), and Brooke et al (2016). Moreover, the Brooke et al (2016) reference is used as the basis for an empirical improvement of the coefficients.…”

Section: Introductionmentioning

confidence: 99%

OH level populations and accuracies of Einstein-A coefficients from hundreds of measured lines

et al. 2020

View full text Add to dashboard Cite

Abstract. OH airglow is an important nocturnal emission of the Earth's mesopause region. As it is chemiluminescent radiation in a thin medium, the population distribution over the various roto-vibrational OH energy levels of the electronic ground state is not in local thermodynamic equilibrium (LTE). In order to better understand these non-LTE effects, we studied hundreds of OH lines in a high-quality mean spectrum based on observations with the high-resolution Ultraviolet and Visual Echelle Spectrograph at Cerro Paranal in Chile. Our derived populations cover vibrational levels between v=3 and 9, rotational levels up to N=24, and individual Λ-doublet components when resolved. As the reliability of these results critically depends on the Einstein-A coefficients used, we tested six different sets and found clear systematic errors in all of them, especially for Q-branch lines and individual Λ-doublet components. In order to minimise the deviations in the populations for the same upper level, we used the most promising coefficients from Brooke et al. (2016) and further improved them with an empirical correction approach. The resulting rotational level populations show a clear bimodality for each v, which is characterised by a probably fully thermalised cold component and a hot population where the rotational temperature increases between v=9 and 4 from about 700 to about 7000 K, and the corresponding contribution to the total population at the lowest N decreases by an order of magnitude. The presence of the hot populations causes non-LTE contributions to rotational temperatures at low N, which can be estimated quite robustly based on the two-temperature model. The bimodality is also clearly indicated by the dependence of the populations on changes in the effective emission height of the OH emission layer. The degree of thermalisation decreases with increasing layer height due to a higher fraction of the hot component. Our high-quality population data are promising with respect to a better understanding of the OH thermalisation process.

show abstract

Section: Introductionmentioning

confidence: 99%

OH level populations and accuracies of Einstein-A coefficients from hundreds of measured lines

et al. 2020

View full text Add to dashboard Cite

show abstract

“…The behavior of planetary-scale oscillations in the mesosphere and lower thermosphere (MLT) region during SSW events has been studied extensively via optical methods (e.g., Reisin et al, 2014;Takahashi et al, 2006), satellite (e.g., Pancheva et al, 2009), numerical simulations (e.g., Gavrilov et al, 2018;Limpasuvan et al, 2012Limpasuvan et al, , 2016Liu et al, 2004), and meteor radars (e.g., Gong, Li, et al, 2018;Lima et al, 2011;Ma et al, 2017;Stray et al, 2015;Xiong et al, 2018). Based on the Whole Atmosphere Community Climate Model, Limpasuvan et al (2012) suggested that the planetary-scale oscillations in the MLT region could be generated during an SSW and an elevated stratopause event (ESE).…”

Section: Introductionmentioning

confidence: 99%

Study of a Quasi 4‐Day Oscillation During the 2018/2019 SSW Over Mohe, China

Gong

Zhang

et al. 2020

JGR Space Physics

View full text Add to dashboard Cite

We present an analysis of planetary‐scale oscillations during sudden stratospheric warming (SSW) events based on data obtained from a meteor radar located at Mohe (MH, 53.5°N, 122.3°E), the Aura satellite and Modern‐Era Retrospective analysis for Research and Applications, Version 2 data (MERRA2). The planetary‐scale oscillations in the mesosphere and lower thermosphere (MLT) region during eight SSW events from 2012 to 2019 have been statistically investigated. Our analysis reveals that the enhancement or the generation of westward propagating quasi 16‐day oscillation with wavenumber 1 (W1) is a common feature during SSWs over MH. A strong enhancement of the quasi 4‐day oscillation during the 2018/2019 SSW is captured by both radar and satellite observations. The amplified quasi 4‐day oscillation has a period of ~4.3 days in both meridional and zonal winds and with a wavenumber of W2 in the zonal component. Using the meteor radar and MERRA2 data, the vertical structure of the quasi 4‐day oscillation from the stratosphere to the lower thermosphere is derived. The upward propagating feature of the quasi 4‐day oscillation in the meridional component indicates that the oscillation is very likely generated in the lower mesosphere. The mesospheric zonal wind reversal after an elevated stratopause event is observed during the SSW, which results in a negative meridional gradient of the quasi‐geostrophic potential vorticity. Our results not only reveal that the amplified quasi 4‐day oscillation in the MLT region is associated with the 2018/2019 SSW but also suggest that the amplification is originally generated around 60 km due to barotropic/baroclinic instability and propagates upward to MLT region.

show abstract

“…The latter is important since the OH emission peak heights depend on v ′ (Adler- Golden, 1997;Xu et al, 2012;von Savigny et al, 2012). The temperature profiles are derived from the SABER CO 2 channels under the consideration of non-LTE effects (Mertens et al, 2001(Mertens et al, , 2004Remsberg et al, 2008;Rezac et al, 2015). TIMED has a slowly-precessing polar orbit, which allows a 24 h coverage at low and mid-latitudes within about 60 days (Russell et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Comparison of VLT/X-shooter OH and O2 rotational temperatures with consideration of TIMED/SABER emission and temperature profiles

et al. 2016

View full text Add to dashboard Cite

Rotational temperatures T rot derived from lines of the same OH band are an important method to study the dynamics and long-term trends in the mesopause region near 87 km. To measure realistic temperatures, the rotational level populations have to be in local thermodynamic equilibrium (LTE). However, this might not be fulfilled, especially at high emission altitudes. In order to quantify possible non-LTE contributions to the OH T rot as a function of the upper vibrational level v ′ , we studied a sample of 343 echelle spectra taken with the X-shooter spectrograph at the Very Large Telescope at Cerro Paranal in Chile. These data allowed us to analyse 25 OH bands in each spectrum. Moreover, we could measure lines of O 2 b(0-1), which peaks at about 94 to 95 km, and O 2 a(0-0) with an emission peak at about 90 km. The latter altitude is reached in the second half of the night after a rise of several km because of the decay of a daytime population of excited O 2 . Since the radiative lifetimes for the upper levels of the two O 2 bands are relatively long, the derived T rot are not significantly affected by non-LTE contributions. These bands are well suited for a comparison with OH if the differences in the emission profiles are corrected. For different sample averages, we made these corrections by using OH emission, O 2 a(0-0) emission, and CO 2 -based temperature profile data from the multi-channel radiometer SABER on the TIMED satellite. The procedure relies on differences of profile-weighted SABER temperatures. For an O 2 a(0-0)based reference profile at 90 km, we found a good agreement of the O 2 with the SABER-related temperatures, whereas the OH temperatures, especially for the high and even v ′ , showed significant excesses with a maximum of more than 10 K for v ′ = 8. The exact value depends on the selected lines and molecular parameters. We could also find a nocturnal trend towards higher non-LTE effects, particularly for high v ′ . The amplitude of these variations can be about 2 K or less, which tends to be significantly smaller than the total amount of the non-LTE contributions. The variations revealed may be important for dynamical studies based on T rot derived from OH bands with high v ′ .

show abstract

Traveling planetary wave activity from mesopause region airglow temperatures determined by the Network for the Detection of Mesospheric Change (NDMC)

Cited by 36 publications

References 46 publications

OH level populations and accuracies of Einstein-<i>A</i> coefficients from hundreds of measured lines

OH level populations and accuracies of Einstein-<i>A</i> coefficients from hundreds of measured lines

Study of a Quasi 4‐Day Oscillation During the 2018/2019 SSW Over Mohe, China

Comparison of VLT/X-shooter OH and O<sub>2</sub> rotational temperatures with consideration of TIMED/SABER emission and temperature profiles

Contact Info

Product

Resources

About

Traveling planetary wave activity from mesopause region airglow temperatures determined by the Network for the Detection of Mesospheric Change (NDMC)

Cited by 36 publications

References 46 publications

OH level populations and accuracies of Einstein-&lt;i&gt;A&lt;/i&gt; coefficients from hundreds of measured lines

OH level populations and accuracies of Einstein-&lt;i&gt;A&lt;/i&gt; coefficients from hundreds of measured lines

Study of a Quasi 4‐Day Oscillation During the 2018/2019 SSW Over Mohe, China

Comparison of VLT/X-shooter OH and O&lt;sub&gt;2&lt;/sub&gt; rotational temperatures with consideration of TIMED/SABER emission and temperature profiles

Contact Info

Product

Resources

About

OH level populations and accuracies of Einstein-<i>A</i> coefficients from hundreds of measured lines

OH level populations and accuracies of Einstein-<i>A</i> coefficients from hundreds of measured lines

Comparison of VLT/X-shooter OH and O<sub>2</sub> rotational temperatures with consideration of TIMED/SABER emission and temperature profiles