Observation and Interpretation of Hydroxyl Airglow Emissions

1973 ◽  
pp. 184-192 ◽  
Author(s):  
R. L. Gattinger ◽  
A. Vallance Jones
Keyword(s):  
Airglow Emissions ◽  
Hydroxyl Airglow

scholarly journals Twin mesospheric bores observed over Brazilian equatorial region

2016 ◽  
Vol 34 (1) ◽  
pp. 91-96 ◽  
Author(s):  
A. F. Medeiros ◽  
I. Paulino ◽  
M. J. Taylor ◽  
J. Fechine ◽  
H. Takahashi ◽  
...  
Keyword(s):  
Equatorial Region ◽  
Temperature Profiles ◽  
Meteor Radar ◽  
Airglow Emissions

Abstract. Two consecutive mesospheric bores were observed simultaneously by two all-sky cameras on 19 December 2006. The observations were carried out in the northeast of Brazil at two different stations: São João do Cariri (36.5° W, 7.4° S) and Monteiro (37.1° W, 7.9° S), which are by about 85 km apart. The mesospheric bores were observed within an interval of  ∼  3 h in the NIR OH and OI557.7 nm airglow emissions. Both bores propagated to the east and showed similar characteristics. However, the first one exhibited a dark leading front with several trailing waves behind and progressed into a brighter airglow region, while the second bore, observed in the OH layer, was comprised of several bright waves propagating into a darker airglow region. This is the first paper to report events like these, called twin mesospheric bores. The background of the atmosphere during the occurrence of these events was studied by considering the temperature profiles from the TIMED/SABER satellite and wind from a meteor radar.

scholarly journals New insights into OH airglow modelling to derive night-time atomic oxygen and atomic hydrogen in the mesopause region

2018 ◽  
Author(s):  
Tilo Fytterer ◽  
Christian von Savigny ◽  
Martin Mlynczak ◽  
Miriam Sinnhuber
Keyword(s):  
Atomic Hydrogen ◽  
Atomic Oxygen ◽  
Box Model ◽  
Satellite Measurements ◽  
Night Time ◽  
Vibrationally Excited ◽  
Mesopause Region ◽  
Airglow Emissions ◽  
Instrument Configuration ◽  
Best Fit

Abstract. An OH airglow model was developed to derive night-time atomic oxygen (O(3P)) and atomic hydrogen (H) from satellite OH airglow observations in the mesopause region (~ 75–100 km). The OH airglow model is based on the zero dimensional box model CAABA/MECCA-3.72f and was empirically adjusted to fit four different OH airglow emissions observed by the satellite/instrument configuration TIMED/SABER at 2.0 μm and at 1.6 μm as well as measurements by ENVISAT/SCIAMACHY of the transitions OH(6-2) and OH(3-1). Comparisons between the Best fit model obtained here and the satellite measurements suggest that deactivation of vibrationally excited OH(v) via OH(v ≥ 7) + O2 might favour relaxation to OH(v' ≤ 5) + O2 by multi-quantum quenching. It is further indicated that the deactivation pathway to OH(v' = v − 5) + O2 dominates. The results also provide general support of the recently proposed mechanism OH(v) + O(3P) → OH(0 ≤ v' ≤ v − 5) + O(1D) but suggest slower rates of OH(v = 7,6,5) + O(3P). Additionally, deactivation to OH(v' = v − 5) + O(1D) might be preferred. The profiles of O(3P) and H derived here are plausible between 80 km and 95  km. The values of O(3P) obtained in this study agree with the corresponding TIMED/SABER values between 80 km and 85 km, but are larger from 85 to 95 km due to different relaxation assumptions of OH(v) + O(3P). The H profile found here is generally larger than TIMED/SABER H by about 30–35 % from 80 to 95 km, which might be attributed to too high O3 night-time values.

scholarly journals Airglow Derived Measurements of Q-Branch Transition Probabilities for Several Hydroxyl Meinel Bands

Atmosphere ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 637 ◽  
Author(s):  
Christoph Franzen ◽  
Patrick Joseph Espy ◽  
Niklas Hofmann ◽  
Robert Edward Hibbins ◽  
Anlaug Amanda Djupvik
Keyword(s):  
High Resolution ◽  
Spontaneous Emission ◽  
Transition Probabilities ◽  
High Signal ◽  
Hitran Database ◽  
Signal To Noise ◽  
Optical Telescope ◽  
Spectroscopic Observations ◽  
Emission Transition ◽  
Airglow Emissions

Spectroscopic measurements of the hydroxyl (OH) airglow emissions are often used to infer neutral temperatures near the mesopause. Correct Einstein coefficients for the various transitions in the OH airglow are needed to calculate accurate temperatures. However, studies from some studys showed experimentally and theoretically that the most commonly used Einstein spontaneous emission transition probabilities for the Q-branch of the OH Meinel (6,2) transition are overestimated. Extending their work to several Δv = 2 and 3 transitions from v′ = 3 to 9, we have determined Einstein coefficients for the first four Q-branch rotational lines. These have been derived from high resolution, high signal to noise spectroscopic observations of the OH airglow in the night sky from the Nordic Optical Telescope. The Q-branch Einstein coefficients calculated from these spectra show that values currently tabulated in the HITRAN database overestimate many of the Q-branch transition probabilities. The implications for atmospheric temperatures derived from OH Q-branch measurements are discussed.

Polar airglow and aurora

1991 ◽  
Vol 69 (8-9) ◽  
pp. 1055-1058 ◽  
Author(s):  
D. J. McEwen ◽  
D. A. Harrington
Keyword(s):  
Magnetic Field ◽  
Statistical Study ◽  
Geomagnetic Latitude ◽  
Great Variability ◽  
Electron Precipitation ◽  
Polar Cap ◽  
Winter Solstice ◽  
Latitude Range ◽  
Precipitation Occurrence ◽  
Airglow Emissions

A survey of night airglow emissions in the polar cap shows stable emission intensities during quiet periods through the winter solstice. Those affected by particle precipitation, OI λ5577 and λ6300, show great variability with solar activity and the state of the interplanetary magnetic field. A statistical study of electron-precipitation occurrence above 78° geomagnetic latitude shows events sufficient to result in observable enhancements in OI emission intensities in about 40% of the satellite passes in the magnetic latitude range from 79° to 83° and in about 15% of the passes for latitudes above 85°. This study provides the necessary background for dynamical studies of polar processes in the planned Canadian polar observatory.

scholarly journals Neutral temperature and atmospheric water vapour retrieval from spectral fitting of auroral and airglow emissions

2018 ◽  
Author(s):  
Joshua M. Chadney ◽  
Daniel K. Whiter
Keyword(s):  
Water Vapour ◽  
Atmospheric Parameter ◽  
Atmospheric Parameters ◽  
Atmospheric Water ◽  
Echelle Spectrograph ◽  
Atmospheric Water Vapour ◽  
Spectral Fitting ◽  
Fitting Method ◽  
Airglow Emissions ◽  
High Throughput Imaging

Abstract. We have developed a spectral fitting method to retrieve upper atmospheric parameters at multiple altitudes simultaneously during times of aurora, allowing us to measure neutral temperatures and column densities of water vapour. We use the method to separate airglow OH emissions from auroral O+ and N2 in observations between 725–740 nm using the High Throughput Imaging Echelle Spectrograph (HiTIES), located on Svalbard. In this paper, we describe our new method and show the results of Monte-Carlo simulations using synthetic spectra which demonstrate the validity of the spectral fitting method as well as provide an indication of uncertainties on the retrieval of each atmospheric parameter.

An update on the hydroxyl airglow temperature record from the Auroral Station in Adventdalen, Svalbard (1980–2005)

2007 ◽  
Vol 85 (2) ◽  
pp. 143-151 ◽  
Author(s):  
M E Dyrland ◽  
F Sigernes
Keyword(s):  
Solar Rotation ◽  
Temperature Fluctuations ◽  
Winter Temperature ◽  
Temperature Record ◽  
Positive Temperature ◽  
Spectral Measurements ◽  
Daily Average ◽  
Winter Temperatures ◽  
Hydroxyl Airglow ◽  
Average Winter Temperature

This paper reports on the daily mesospheric winter temperature series derived from ground-based spectral measurements of the hydroxyl airglow layer from the Auroral Station in Adventdalen near Longyearbyen, Svalbard (78°N, 15°E). Temperature estimates from the four latest seasons (2001–2002 to 2004–2005) have been added to the series reported by Sigernes et al. J. Geophys. Res. 108(A9), 1342 (2003). Lomb–Scargle periodogram analyses were performed on both hourly and daily average temperatures to look for significant periods. From the daily means, ∼24 and ∼26 d oscillations that are consistent with a solar rotation modulation of the atmosphere were identified. Analyses of the hourly averaged data did not reveal any considerable diurnal and semidiurnal periods in the temperatures. The 2003–2004 mesopause winter was one of the warmest reported over Svalbard during the last 25 years. It is common to observe within a few days temperature fluctuations in the range 20–40 K. Some years show far less variation than others. The overall daily average winter temperature is 209 K. The annual mean winter temperatures show a slightly positive temperature trend (+0.2 ± 0.1 K/year), on the verge of being a statistically significant change in the winter mesospheric temperatures over Svalbard.PACS Nos.: 92.60.hc, 07.20.Dt, 93.30.Sq, 92.60.hw

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