Several notes on the OH* layer

Grygalashvyly, M.

doi:10.5194/angeo-33-923-2015

Cited by 25 publications

(20 citation statements)

References 73 publications

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“…The assumption of PEO was applied to studying the mesospheric OH* layer response to gravity waves (Swenson & Gardner, 1998). In some theoretical papers (e.g., Grygalashvyly, 2015;Grygalashvyly et al, 2014) the PEO assumption was used to derive the dependence of excited hydroxyl layer number density and altitude on atomic oxygen and temperature. In the paper by Sonnemann et al (2015), it was employed for analysis of annual variations of the OH* layer.…”

Section: Introductionmentioning

confidence: 99%

Nighttime Ozone Chemical Equilibrium in the Mesopause Region

et al. 2018

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We examine the applicability of the assumption that nighttime ozone is in photochemical equilibrium. The analysis is based on calculations with a 3‐D chemical transport model. These data are used to determine the ratio of correct (calculated) O3 density to its equilibrium value for the conditions of the nighttime mesosphere depending on the altitude, latitude, and month in the annual cycle. The results obtained demonstrate that the retrieval of O and H distributions using the assumption of photochemical ozone equilibrium may lead to a significant error below 81–87 km depending on season. Possible modifications of the currently used approach that allow improving the quality of retrieval of O and H mesospheric distributions from satellite‐based observations are discussed.

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Section: Introductionmentioning

confidence: 99%

Nighttime Ozone Chemical Equilibrium in the Mesopause Region

et al. 2018

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“…The radiative decay of OH(v) in the visible and infrared regions of the electromagnetic spectrum, known as the OH Meinel band emission, is a prominent feature in night sky spectra. The OH Meinel band emission has been used to monitor atmospheric density changes, temperature fluctuations, and species concentrations for several decades (Meriwether, 1989;Sivjee, 1992;Khomich et al, 2008;Grygalashvyly, 2015).…”

Section: Introductionmentioning

confidence: 99%

Technical note: Bimodality in mesospheric OH rotational population distributions and implications for temperature measurements

Kalogerakis

2019

Atmos. Chem. Phys.

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Abstract. Emissions from the OH Meinel bands are routinely used to determine rotational temperatures that are considered proxies for the kinetic temperature near the mesopause region. Previous observations determined OH rotational temperatures that show a dependence on the vibrational level, with the temperature rising overall as the OH vibrational quantum number v increases. The source of this trend is not well understood and has generally been attributed to deviations from thermodynamic equilibrium. This technical note demonstrates that the existence of bimodal OH rotational population distributions is an inherent feature of rotational relaxation in gases and can provide an explanation for the previously reported temperature trend. The use of only a few lines from rotational transitions involving low rotational quantum numbers to determine rotational temperatures does not account for the bimodality of the OH rotational population distributions and leads to systematic errors overestimating the OH rotational temperature. This note presents selected examples, discusses the relevant implications, and considers strategies that could lead to more reliable OH rotational temperature determination.

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“…The PEO assumption was employed for studying the mesospheric OH* layer response to gravity waves (Swenson and Gardner, 1998). In ultimately theoretical works, e.g., Grygalashvyly et al (2014) and Grygalashvyly (2015), PEO was used to derive the dependence of excited hydroxyl layer concentration and altitude on atomic oxygen and temperature. In the paper by Sonnemann et al (2015) it was used to analyze annual variations of the OH* layer.…”

Section: Introductionmentioning

confidence: 99%

Technical note: Evaluation of the simultaneous measurements of mesospheric OH, HO<sub>2</sub>, and O<sub>3</sub> under a photochemical equilibrium assumption – a statistical approach

et al. 2018

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Abstract. This Technical Note presents a statistical approach to evaluating simultaneous measurements of several atmospheric components under the assumption of photochemical equilibrium. We consider simultaneous measurements of OH, HO 2 , and O 3 at the altitudes of the mesosphere as a specific example and their daytime photochemical equilibrium as an evaluating relationship. A simplified algebraic equation relating local concentrations of these components in the 50-100 km altitude range has been derived. The parameters of the equation are temperature, neutral density, local zenith angle, and the rates of eight reactions. We have performed a one-year simulation of the mesosphere and lower thermosphere using a 3-D chemical-transport model. The simulation shows that the discrepancy between the calculated evolution of the components and the equilibrium value given by the equation does not exceed 3-4 % in the full range of altitudes independent of season or latitude. We have developed a statistical Bayesian evaluation technique for simultaneous measurements of OH, HO 2 , and O 3 based on the equilibrium equation taking into account the measurement error. The first results of the application of the technique to MLS/Aura data (Microwave Limb Sounder) are presented in this Technical Note. It has been found that the satellite data of the HO 2 distribution regularly demonstrate lower altitudes of this component's mesospheric maximum. This has also been confirmed by model HO 2 distributions and comparison with offline retrieval of HO 2 from the daily zonal means MLS radiance.

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Several notes on the OH* layer

Cited by 25 publications

References 73 publications

Nighttime Ozone Chemical Equilibrium in the Mesopause Region

Nighttime Ozone Chemical Equilibrium in the Mesopause Region

Technical note: Bimodality in mesospheric OH rotational population distributions and implications for temperature measurements

Technical note: Evaluation of the simultaneous measurements of mesospheric OH, HO<sub>2</sub>, and O<sub>3</sub> under a photochemical equilibrium assumption – a statistical approach

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Several notes on the OH* layer

Cited by 25 publications

References 73 publications

Nighttime Ozone Chemical Equilibrium in the Mesopause Region

Nighttime Ozone Chemical Equilibrium in the Mesopause Region

Technical note: Bimodality in mesospheric OH rotational population distributions and implications for temperature measurements

Technical note: Evaluation of the simultaneous measurements of mesospheric OH, HO&lt;sub&gt;2&lt;/sub&gt;, and O&lt;sub&gt;3&lt;/sub&gt; under a photochemical equilibrium assumption – a statistical approach

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Technical note: Evaluation of the simultaneous measurements of mesospheric OH, HO<sub>2</sub>, and O<sub>3</sub> under a photochemical equilibrium assumption – a statistical approach