scholarly journals Photochemical modeling of molecular and atomic oxygen based on multiple nightglow emissions measured in situ during the Energy Transfer in the Oxygen Nightglow rocket campaign

2020 ◽  
Vol 20 (4) ◽  
pp. 2221-2261 ◽  
Author(s):  
Olexandr Lednyts'kyy ◽  
Christian von Savigny
Keyword(s):  
Energy Transfer ◽  
Atomic Oxygen ◽  
A Priori ◽  
Lower Thermosphere ◽  
Reaction Rates ◽  
Data Sets ◽  
Electronically Excited ◽  
Photochemical Modeling ◽  
Mlt Region

Abstract. Electronically excited states of molecular and atomic oxygen (six O2 and two O) were implemented in the proposed Multiple Airglow Chemistry (MAC) model as minor species coupled with each other as well as with the ground states of O2 and O to represent the photochemistry in the upper mesosphere and lower thermosphere (MLT) region. The MAC model combines chemical processes of well-known photochemical models related to identified O2 and O species and some additional processes. Concentrations of excited O2 and O species were retrieved using the MAC model on the basis of the multiple nightglow emissions measured in situ during the Energy Transfer in the Oxygen Nightglow (ETON) rocket campaign. The proposed retrieval procedure to obtain the concentrations of these minor species in the MLT region is implemented by avoiding a priori data sets. Unknown and poorly constrained reaction rates were tuned, and the reaction rates of the well-known models were updated with the MAC model by comparing in situ and evaluated emission profiles as well as in situ and retrieved O concentration profiles. As a result, precursors of O2 and O species responsible for the transitions considered in the MAC model are identified and validated.

scholarly journals Photochemical modeling of molecular and atomic oxygen based on multiple <i>in-situ</i> emissions measured during the Energy Transfer in the Oxygen Nightglow rocket campaign

2019 ◽  
Author(s):  
Olexandr Lednyts'kyy ◽  
Christian von Savigny
Keyword(s):  
Energy Transfer ◽  
Atomic Oxygen ◽  
A Priori ◽  
Lower Thermosphere ◽  
Reaction Rates ◽  
Data Sets ◽  
Electronically Excited ◽  
Photochemical Modeling ◽  
Mlt Region

Abstract. Electronically excited states of molecular and atomic oxygen (six of O2 and two of O) were implemented in the proposed Multiple Airglow Chemistry (MAC) model as minor species coupled with each other as well as with the ground states of O2 and O to represent the photochemistry in the upper Mesosphere and Lower Thermosphere (MLT) region. The MAC model is proposed combining chemical processes of the well-known photochemical models related to identified O2 and O species and some additional processes. Concentrations of excited O2 and O species were retrieved using the MAC model on the basis of the multiple in-situ nightglow emissions measured during the Energy Transfer in the Oxygen Nightglow (ETON) rocket campaign. The proposed retrieval procedure to obtain concentrations of these MLT minor species is implemented avoiding a priori data sets. Unknown and poorly constrained reaction rates were tuned and reaction rates of the well-known models were updated with the MAC model comparing in-situ and evaluated emission profiles as well as in-situ and retrieved O concentration profiles. As a result, precursors of O2 and O species responsible for transitions considered in the MAC model are identified and validated by calculations with the MAC model.

scholarly journals Simultaneous in situ measurements of small-scale structures in neutral, plasma, and atomic oxygen densities during the WADIS sounding rocket project

2019 ◽  
Vol 19 (17) ◽  
pp. 11443-11460 ◽  
Author(s):  
Boris Strelnikov ◽  
Martin Eberhart ◽  
Martin Friedrich ◽  
Jonas Hedin ◽  
Mikhail Khaplanov ◽  
...  
Keyword(s):  
Atomic Oxygen ◽  
Lower Thermosphere ◽  
Density Fluctuations ◽  
Sounding Rocket ◽  
Small Scale ◽  
Scale Structures ◽  
Small Scale Structures ◽  
Mlt Region ◽  
Diffusion Properties

Abstract. In this paper we present an overview of measurements conducted during the WADIS-2 rocket campaign. We investigate the effect of small-scale processes like gravity waves and turbulence on the distribution of atomic oxygen and other species in the mesosphere–lower thermosphere (MLT) region. Our analysis suggests that density fluctuations of atomic oxygen are coupled to fluctuations of other constituents, i.e., plasma and neutrals. Our measurements show that all measured quantities, including winds, densities, and temperatures, reveal signatures of both waves and turbulence. We show observations of gravity wave saturation and breakdown together with simultaneous measurements of generated turbulence. Atomic oxygen inside turbulence layers shows two different spectral behaviors, which might imply a change in its diffusion properties.

The Momentum Budget in the Stratosphere, Mesosphere, and Lower Thermosphere. Part II: The In Situ Generation of Gravity Waves

2018 ◽  
Vol 75 (10) ◽  
pp. 3635-3651 ◽  
Author(s):  
Ryosuke Yasui ◽  
Kaoru Sato ◽  
Yasunobu Miyoshi
Keyword(s):  
Gravity Wave ◽  
Gravity Waves ◽  
Lower Thermosphere ◽  
Shear Instability ◽  
Wave Forcing ◽  
Momentum Budget ◽  
Mesosphere And Lower Thermosphere ◽  
In Situ Generation ◽  
Mlt Region

The contributions of gravity waves to the momentum budget in the mesosphere and lower thermosphere (MLT) is examined using simulation data from the Ground-to-Topside Model of Atmosphere and Ionosphere for Aeronomy (GAIA) whole-atmosphere model. Regardless of the relatively coarse model resolution, gravity waves appear in the MLT region. The resolved gravity waves largely contribute to the MLT momentum budget. A pair of positive and negative Eliassen–Palm flux divergences of the resolved gravity waves are observed in the summer MLT region, suggesting that the resolved gravity waves are likely in situ generated in the MLT region. In the summer MLT region, the mean zonal winds have a strong vertical shear that is likely formed by parameterized gravity wave forcing. The Richardson number sometimes becomes less than a quarter in the strong-shear region, suggesting that the resolved gravity waves are generated by shear instability. In addition, shear instability occurs in the low (middle) latitudes of the summer (winter) MLT region and is associated with diurnal (semidiurnal) migrating tides. Resolved gravity waves are also radiated from these regions. In Part I of this paper, it was shown that Rossby waves in the MLT region are also radiated by the barotropic and/or baroclinic instability formed by parameterized gravity wave forcing. These results strongly suggest that the forcing by gravity waves originating from the lower atmosphere causes the barotropic/baroclinic and shear instabilities in the mesosphere that, respectively, generate Rossby and gravity waves and suggest that the in situ generation and dissipation of these waves play important roles in the momentum budget of the MLT region.

OSAS-B: a balloon-borne heterodyne spectrometer for sounding atomic oxygen in the MLT region

2021 ◽  
Author(s):  
Martin Wienold ◽  
Alexey Semenov ◽  
Heiko Richter ◽  
Heinz-Wilhelm Hübers
Keyword(s):  
Atomic Oxygen ◽  
Near Infrared ◽  
Lower Thermosphere ◽  
Local Oscillator ◽  
Hot Electron ◽  
Water Vapor Absorption ◽  
Mesosphere And Lower Thermosphere ◽  
Spectrally Resolved ◽  
Heterodyne Spectrometer ◽  
Mlt Region

&lt;p&gt;The Oxygen Spectrometer for Atmospheric Science on a Balloon (OSAS-B) is dedicated to the remote sounding of atomic oxygen in the mesosphere and lower thermosphere (MLT) region of Earth's atmosphere, where atomic oxygen is the dominant species. Quantitative radiometry of atomic oxygen via its visible and near-infrared transitions has been difficult, due to the complex excitation physics involved. OSAS-B is a heterodyne spectrometer for the thermally excited ground state transition of atomic oxygen at 4.75 THz. It will enable spectrally resolved measurements of the line shape, &amp;#160;which in turn enables the determination of the concentration of atomic oxygen in the MLT. Due to water absorption, this line can only be observed from high-altitude platforms such as a high-flying airplanes, balloons or satellites. Recently the first spectrally resolved observation of the 4.75-THz line has been reported using a heterodyne spectrometer on SOFIA, the Stratospheric Observatory for Infrared Astronomy [1]. Compared to SOFIA a balloon-borne instrument has the advantage of not being hampered by atmospheric water vapor absorption. OSAS-B will comprise a hot-electron bolometer mixer and a quantum-cascade laser as local oscillator in a combined helium/nitrogen dewar. A turning mirror will allow for sounding at different vertical inclinations. The&amp;#160; first flight of OSAS-B is planned for autumn 2022 in the frame of the European HEMERA project [2].&lt;/p&gt;&lt;p&gt;[1] H. Richter et al., Direct measurements of atomic oxygen in the mesosphere and lower thermosphere using terahertz heterodyne spectroscopy, accepted for publication in Communications Earth &amp; Environment (2021).&lt;/p&gt;&lt;p&gt;[2] https://www.hemera-h2020.eu/&lt;/p&gt;

scholarly journals Simultaneous in situ measurements of small-scale structures in neutral, plasma, and atomic oxygen densities during WADIS sounding rocket project

2019 ◽  
Author(s):  
Boris Strelnikov ◽  
Martin Eberhart ◽  
Martin Friedrich ◽  
Jonas Hedin ◽  
Mikhail Khaplanov ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Atomic Oxygen ◽  
Density Fluctuations ◽  
Sounding Rocket ◽  
Small Scale ◽  
Scale Structures ◽  
Small Scale Structures ◽  
Mlt Region ◽  
Diffusion Properties

Abstract. In this paper we present an overview of measurements conducted during the WADIS-2 rocket campaign. We investigate the effect of small-scale processes like gravity waves and turbulence on the distribution of atomic oxygen and other species in the MLT region. Our analysis suggests that density fluctuations of atomic oxygen are coupled to fluctuations of other constituents, i.e., plasma and neutrals. Our measurements show that all measured quantities, including winds, densities, and temperatures, reveal signatures of both waves and turbulence. We show observations of gravity wave saturation and breakdown together with simultaneous measurements of generated turbulence. Atomic oxygen inside turbulence layers shows two different spectral behaviors, which might imply change of its diffusion properties.

scholarly journals Atomic oxygen number densities in the MLT region measured by solid electrolyte sensors on WADIS-2

2018 ◽  
Author(s):  
Martin Eberhart ◽  
Stefan Löhle ◽  
Boris Strelnikov ◽  
Jonas Hedin ◽  
Mikhail Khaplanov ◽  
...  
Keyword(s):  
Solid Electrolyte ◽  
Atomic Oxygen ◽  
Molecular Beam ◽  
Sensor Data ◽  
Atmospheric Models ◽  
Density Profiles ◽  
Amperometric Sensors ◽  
High Vertical Resolution ◽  
Mlt Region

Abstract. Absolute profiles of atomic oxygen number densities with high vertical resolution have been determined in the MLT region from in-situ measurements by several rocket-borne solid electrolyte sensors. The amperometric sensors were operated in both controlled and uncontrolled modes and with various orientations on the fore and aft deck of the payload. Calibration was based on mass spectrometry in a molecular beam containing atomic oxygen produced in a microwave discharge. The sensor signal is proportional to the number flux onto the electrodes and the mass flow rate in the molecular beam was measured additionally to derive this quantity from the spectrometer reading. Numerical simulations provided aerodynamic correction factors to derive the atmospheric number density of atomic oxygen from the sensor data. The flight results indicate a preferable orientation of the electrode surface perpendicular to the rocket axis. While unstable during the upleg, the density profiles measured by these sensors show an excellent agreement with the atmospheric models and photometer results during the downleg of the trajectory. The high spatial resolution of the measurements allows the identification of small-scaled variations in the atomic oxygen concentration.

scholarly journals Comparison of GOME tropospheric NO<sub>2</sub> columns with NO<sub>2</sub> profiles deduced from ground-based in situ measurements

2006 ◽  
Vol 6 (11) ◽  
pp. 3211-3229 ◽  
Author(s):  
D. Schaub ◽  
K. F. Boersma ◽  
J. W. Kaiser ◽  
A. K. Weiss ◽  
D. Folini ◽  
...  
Keyword(s):  
Standard Deviation ◽  
A Priori ◽  
Relative Difference ◽  
In Situ Measurements ◽  
Data Sets ◽  
Clear Sky ◽  
Tropospheric No2 ◽  
The Mean ◽  
Sky Conditions

Abstract. Nitrogen dioxide (NO2) vertical tropospheric column densities (VTCs) retrieved from the Global Ozone Monitoring Experiment (GOME) are compared to coincident ground-based tropospheric NO2 columns. The ground-based columns are deduced from in situ measurements at different altitudes in the Alps for 1997 to June 2003, yielding a unique long-term comparison of GOME NO2 VTC data retrieved by a collaboration of KNMI (Royal Netherlands Meteorological Institute) and BIRA/IASB (Belgian Institute for Space Aeronomy) with independently derived tropospheric NO2 profiles. A first comparison relates the GOME retrieved tropospheric columns to the tropospheric columns obtained by integrating the ground-based NO2 measurements. For a second comparison, the tropospheric profiles constructed from the ground-based measurements are first multiplied with the averaging kernel (AK) of the GOME retrieval. The second approach makes the comparison independent from the a priori NO2 profile used in the GOME retrieval. This allows splitting the total difference between the column data sets into two contributions: one that is due to differences between the a priori and the ground-based NO2 profile shapes, and another that can be attributed to uncertainties in both the remaining retrieval parameters (such as, e.g., surface albedo or aerosol concentration) and the ground-based in situ NO2 profiles. For anticyclonic clear sky conditions the comparison indicates a good agreement between the columns (n=157, R=0.70/0.74 for the first/second comparison approach, respectively). The mean relative difference (with respect to the ground-based columns) is −7% with a standard deviation of 40% and GOME on average slightly underestimating the ground-based columns. Both data sets show a similar seasonal behaviour with a distinct maximum of spring NO2 VTCs. Further analysis indicates small GOME columns being systematically smaller than the ground-based ones. The influence of different shapes in the a priori and the ground-based NO2 profile is analysed by considering AK information. It is moderate and indicates similar shapes of the profiles for clear sky conditions. Only for large GOME columns, differences between the profile shapes explain the larger part of the relative difference. In contrast, the other error sources give rise to the larger relative differences found towards smaller columns. Further, for the clear sky cases, errors from different sources are found to compensate each other partially. The comparison for cloudy cases indicates a poorer agreement between the columns (n=60, R=0.61). The mean relative difference between the columns is 60% with a standard deviation of 118% and GOME on average overestimating the ground-based columns. The clear improvement after inclusion of AK information (n=60, R=0.87) suggests larger errors in the a priori NO2 profiles under cloudy conditions and demonstrates the importance of using accurate profile information for (partially) clouded scenes.

scholarly journals Optimal estimation of tropospheric H<sub>2</sub>O and δD with IASI/METOP

2011 ◽  
Vol 11 (21) ◽  
pp. 11207-11220 ◽  
Author(s):  
M. Schneider ◽  
F. Hase
Keyword(s):  
A Priori ◽  
Measurement Techniques ◽  
Lower Troposphere ◽  
Optimal Estimation ◽  
Atmospheric Temperature ◽  
Data Sets ◽  
Upper Troposphere ◽  
Systematic Uncertainties ◽  
Better Than

Abstract. We present optimal estimates of tropospheric H2O and δD derived from radiances measured by the instrument IASI (Infrared Atmospheric Sounding Interferometer) flown on EUMETSAT's polar orbiter METOP. We document that the IASI spectra allow for retrieving H2O profiles between the surface and the upper troposphere as well as middle tropospheric δD values. A theoretical error estimation suggests a precision for H2O of better than 35% in the lower troposphere and of better than 15% in the middle and upper troposphere, respectively, whereby surface emissivity and atmospheric temperature uncertainties are the leading error sources. For the middle tropospheric δD values we estimate a precision of 15–20‰ with the measurement noise being the dominating error source. The accuracy of the IASI products is estimated to about 20–10% and 10‰ for lower to upper tropospheric H2O and middle tropospheric δD, respectively. It is limited by systematic uncertainties in the applied spectroscopic parameters and the a priori atmospheric temperature profiles. We compare our IASI products to a large number of near coincident radiosonde in-situ and ground-based FTS (Fourier Transform Spectrometer) remote sensing measurements. The bias and the scatter between the different H2O and δD data sets are consistent with the combined theoretical uncertainties of the involved measurement techniques.

scholarly journals Comparison of GOME tropospheric NO<sub>2</sub> columns with NO<sub>2</sub> profiles deduced from ground-based in situ measurements

2006 ◽  
Vol 6 (2) ◽  
pp. 2189-2239
Author(s):  
D. Schaub ◽  
K. F. Boersma ◽  
J. W. Kaiser ◽  
A. K. Weiss ◽  
D. Folini ◽  
...  
Keyword(s):  
Standard Deviation ◽  
A Priori ◽  
Relative Difference ◽  
In Situ Measurements ◽  
Data Sets ◽  
Clear Sky ◽  
Tropospheric No2 ◽  
The Mean ◽  
Sky Conditions

Abstract. Nitrogen dioxide (NO2) vertical tropospheric column densities (VTCs) retrieved from the Global Ozone Monitoring Experiment (GOME) are compared to coincident ground-based tropospheric NO2 columns. The ground-based columns are deduced from in situ measurements at different altitudes in the Alps for 1997 to June 2003, yielding a unique long-term comparison of GOME NO2 VTC data retrieved by KNMI/BIRA with independently derived tropospheric NO2 profiles. A first comparison relates the GOME columns to the ground-based NO2 profiles that are directly integrated to tropospheric columns. A second comparison includes averaging kernel (AK) information, which makes the comparison independent from the a priori NO2 profile used in the GOME retrieval. This allows splitting the total difference between the column data sets into two contributions: one that is due to differences between the a priori and the ground-based NO2 profile shapes, and another that can be attributed to uncertainties in both the remaining retrieval parameters and the ground-based in situ NO2 profiles. For anticyclonic clear sky conditions the comparison indicates a good agreement between the columns (n=157, R=0.70/0.74 without/with AK included). Both data sets show a similar seasonal behaviour with a distinct maximum of spring NO2 VTCs. The mean relative difference (with respect to the ground-based columns) is −7% with a standard deviation of 40% and GOME on average slightly underestimating the ground-based columns. Further analysis indicates small GOME columns being systematically smaller than the ground-based ones. The influence of different shapes in the a priori and the ground-based NO2 profile is analysed by considering AK information. It is moderate and indicates similar shapes of the profiles for clear sky conditions. Only for large GOME columns, differences between the profile shapes explain the larger part of the relative difference. In contrast, the other error sources give rise to the larger relative differences found towards smaller columns. Further, for the clear sky cases, errors from different sources are found to compensate each other partially. The comparison for cloudy cases indicates a poorer agreement between the columns (n=60, R=0.61). The mean relative difference between the columns is 60% with a standard deviation of 118% and GOME on average overestimating the ground-based columns. The clear improvement after inclusion of AK information (n=60, R=0.87) suggests larger errors in the a priori NO2 profiles under cloudy conditions and demonstrates the importance of using the kernel information for (partially) clouded scenes.

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