Photodissociation rates of molecular oxygen in the mesosphere and lower thermosphere

Atmospheric emissions of atomic and molecular oxygen have been observed since the middle of the 19th century. In the last decades, it has been shown that emissions of excited oxygen atom O(1D) and molecular oxygen in electronically-vibrationally excited states O2(b1&#931;+g, v) and O2(a1&#916;g, v) are related by a unified photochemical mechanism in the mesosphere and lower thermosphere (MLT). The current study is performed in the framework of the state-of-the-art model of ozone and molecular oxygen photodissociation in the daytime MLT. In particular, the study includes a detailed description of the formation mechanism for excited oxygen components in the daytime MLT and presents the comparison of widely used photochemical models. The study also demonstrates new results such as i) new suggestions about possible products of collisional reactions of electronically-vibrationally excited oxygen molecules with atomic oxygen and ii) new estimates of O2(b1&#931;+g, v = 0 &#8211; 10) radiative lifetimes which are necessary for solving inverse problems in the lower thermosphere. Moreover, special attention is given to the Barth&#8217;s mechanism in order to demonstrate that its contribution to O2(b1&#931;+g, v) and O2(a1&#916;g, v) populations is neglectable in daytime conditions regardless of fitting coefficients. In addition, possible applications of the daytime oxygen emissions are presented, e.g., the altitude profiles O(3P), O3 and CO2 can be retrieved by solving inverse photochemical problems where emissions from electronically vibrationally excited states of O2 are used as proxies. The funding of V.Y., R.M. and I.M. was partly provided by the Russian Fund for Basic Research (grant RFBR No. 20-05-00450).

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Changes in molecular oxygen and hydroxyl airglow of the mesosphere and lower thermosphere as observed at Zvenigorod in 2000-2019

26th International Symposium on Atmospheric and Ocean Optics, Atmospheric Physics ◽

10.1117/12.2575633 ◽

2020 ◽

Author(s):

Vladimir Perminov ◽

Nikolay Pertsev ◽

Peter Dalin ◽

Yury Zheleznov

Keyword(s):

Molecular Oxygen ◽

Lower Thermosphere ◽

Hydroxyl Airglow ◽

Mesosphere And Lower Thermosphere

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Retrieval of molecular nitrogen and molecular oxygen densities in the upper mesosphere and lower thermosphere using ground-based lidar measurements

Journal of Geophysical Research Atmospheres ◽

10.1029/2000jd900669 ◽

2001 ◽

Vol 106 (D10) ◽

pp. 10313-10323 ◽

Cited By ~ 2

Author(s):

M. M. Mwangi ◽

R. J. Sica ◽

P. S. Argall

Keyword(s):

Molecular Oxygen ◽

Molecular Nitrogen ◽

Lower Thermosphere ◽

Lidar Measurements ◽

Mesosphere And Lower Thermosphere ◽

Ground Based Lidar

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Model of Daytime Oxygen Emissions in the Mesopause Region and Above: A Review and New Results

Atmosphere ◽

10.3390/atmos11010116 ◽

2020 ◽

Vol 11 (1) ◽

pp. 116 ◽

Cited By ~ 2

Author(s):

Valentine Yankovsky ◽

Ekaterina Vorobeva

Keyword(s):

Oxygen Atom ◽

Molecular Oxygen ◽

Excited States ◽

Atomic Oxygen ◽

Lower Thermosphere ◽

Atmospheric Emissions ◽

Vibrationally Excited ◽

Mesopause Region ◽

Mesosphere And Lower Thermosphere ◽

Excited Oxygen

Atmospheric emissions of atomic and molecular oxygen have been observed since the middle of 19th century. In the last decades, it has been shown that emissions of excited oxygen atom O(1D) and molecular oxygen in electronically–vibrationally excited states O2(b1Σ+g, v) and O2(a1Δg, v) are related by a unified photochemical mechanism in the mesosphere and lower thermosphere (MLT). The current paper consists of two parts: a review of studies related to the development of the model of ozone and molecular oxygen photodissociation in the daytime MLT and new results. In particular, the paper includes a detailed description of formation mechanism for excited oxygen components in the daytime MLT and presents comparison of widely used photochemical models. The paper also demonstrates new results such as new suggestions about possible products for collisional reactions of electronically–vibrationally excited oxygen molecules with atomic oxygen and new estimations of O2(b1Σ+g, v = 0–10) radiative lifetimes which are necessary for solving inverse problems in the lower thermosphere. Moreover, special attention is given to the “Barth’s mechanism” in order to demonstrate that for different sets of fitting coefficients its contribution to O2(b1Σ+g, v) and O2(a1Δg, v) population is neglectable in daytime conditions. In addition to the review and new results, possible applications of the daytime oxygen emissions are presented, e.g., the altitude profiles O(3P), O3 and CO2 can be retrieved by solving inverse photochemical problems when emissions from electronically vibrationally excited states of O2 molecule are used as proxies.

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Large-Scale Waves in the Mesosphere and Lower Thermosphere Observed by SABER

Journal of the Atmospheric Sciences ◽

10.1175/jas3612.1 ◽

2005 ◽

Vol 62 (12) ◽

pp. 4384-4399 ◽

Cited By ~ 104

Author(s):

Rolando R. Garcia ◽

Ruth Lieberman ◽

James M. Russell ◽

Martin G. Mlynczak

Keyword(s):

Large Scale ◽

Middle Atmosphere ◽

Lower Thermosphere ◽

Normal Modes ◽

Zonal Winds ◽

Broadband Emission ◽

Summer Hemisphere ◽

Mean Structure ◽

Mesosphere And Lower Thermosphere ◽

The Tropics

Abstract Observations made by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on board NASA’s Thermosphere–Ionosphere–Mesosphere Energetics and Dynamics (TIMED) satellite have been processed using Salby’s fast Fourier synoptic mapping (FFSM) algorithm. The mapped data provide a first synoptic look at the mean structure and traveling waves of the mesosphere and lower thermosphere (MLT) since the launch of the TIMED satellite in December 2001. The results show the presence of various wave modes in the MLT, which reach largest amplitude above the mesopause and include Kelvin and Rossby–gravity waves, eastward-propagating diurnal oscillations (“non-sun-synchronous tides”), and a set of quasi-normal modes associated with the so-called 2-day wave. The latter exhibits marked seasonal variability, attaining large amplitudes during the solstices and all but disappearing at the equinoxes. SABER data also show a strong quasi-stationary Rossby wave signal throughout the middle atmosphere of the winter hemisphere; the signal extends into the Tropics and even into the summer hemisphere in the MLT, suggesting ducting by westerly background zonal winds. At certain times of the year, the 5-day Rossby normal mode and the 4-day wave associated with instability of the polar night jet are also prominent in SABER data.

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