Search for horizontal and vertical variations of CO in the day and night side lower mesosphere of Venus from CSHELL/IRTF <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si0010.gif" overflow="scroll"><mml:mn>4.53</mml:mn><mml:mspace width="0.25em"/><mml:mi mathvariant="normal">μ</mml:mi><mml:mi mathvariant="normal">m</mml:mi></mml:math> observations

Marcq, Emmanuel; Lellouch, E.; Encrenaz, Thérèse; Widemann, Thomas; Birlan, Mirel; Bertaux, Jean-Loup

doi:10.1016/j.pss.2014.12.013

Cited by 30 publications

(3 citation statements)

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“…The fluorescence of CO molecule excited by solar radiation has been observed at 4.53 µm in the upper atmosphere of Venus with high spectral resolving power (R ∼ 43 000) by Marcq et al (2015). The same must happen in the atmosphere of the Earth; introducing a bias of about 1 % on the CO column retrieval (rough estimate) may not be so important because it is well below the currently achieved accuracy of some tens of percent on CO columns.…”

Section: Methods Nomentioning

confidence: 99%

“…The electronic transitions can only happen thanks to the existence of a magnetic dipole moment (M1) and/or a quadrupolar electric moment (E2). As a consequence, spontaneous transitions from a given electronic state down to the fundamental state X 3 − g are unlikely; therefore, the lifetime of such a state is rather long: 13 s for the atmospheric A band at 760 nm, transition (b 1 + g → X 3 − g ) (Mlynczak and Solomon, 1993) and 75 min for the O 2 IR band at 1.27 µm, transition (a 1 g → X 3 − g ) (Lafferty et al, 1998). Therefore, the O 2 molecule excited at level a 1 g (often represented by O 2 * or O 2 ( 1 ) in this paper) which results from ozone photo-dissociation has plenty of time to reach thermal equilibrium with ambient gas, and the various states of vibration rotation will be populated according to a Boltzmann law (therefore, depending on the local temperature T ) modulated by the rotation quantum number J , with a statistical weight 2J + 1 as described later below.…”

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The use of the 1.27 µm O₂ absorption band for greenhouse gas monitoring from space and application to MicroCarb

et al. 2020

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Abstract. Monitoring CO2 from space is essential to characterize the spatiotemporal distribution of this major greenhouse gas and quantify its sources and sinks. The mixing ratio of CO2 to dry air can be derived from the CO2∕O2 column ratio. The O2 column is usually derived from its absorption signature on the solar reflected spectra over the O2 A band (e.g. Orbiting Carbon Observatory-2 (OCO-2), Thermal And Near infrared Sensor for carbon Observation (TANSO)/Greenhouse Gases Observing Satellite (GOSAT), TanSat). As a result of atmospheric scattering, the atmospheric path length varies with the aerosols' load, their vertical distribution, and their optical properties. The spectral distance between the O2 A band (0.76 µm) and the CO2 absorption band (1.6 µm) results in significant uncertainties due to the varying spectral properties of the aerosols over the globe. There is another O2 absorption band at 1.27 µm with weaker lines than in the A band. As the wavelength is much closer to the CO2 and CH4 bands, there is less uncertainty when using it as a proxy of the atmospheric path length to the CO2 and CH4 bands. This O2 band is used by the Total Carbon Column Observing Network (TCCON) implemented for the validation of space-based greenhouse gas (GHG) observations. However, this absorption band is contaminated by the spontaneous emission of the excited molecule O2*, which is produced by the photo-dissociation of O3 molecules in the stratosphere and mesosphere. From a satellite looking nadir, this emission has a similar shape to the absorption signal that is used. In the frame of the CNES (Centre National d'Études Spatiales – the French National Centre for Space Studies) MicroCarb project, scientific studies have been performed in 2016–2018 to explore the problems associated with this O2* airglow contamination and methods to correct it. A theoretical synthetic spectrum of the emission was derived from an approach based on A21 Einstein coefficient information contained in the line-by-line high-resolution transmission molecular absorption (HITRAN) 2016 database. The shape of our synthetic spectrum is validated when compared to O2* airglow spectra observed by the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY)/Envisat in limb viewing. We have designed an inversion scheme of SCIAMACHY limb-viewing spectra, allowing to determine the vertical distribution of the volume emission rate (VER) of the O2* airglow. The VER profiles and corresponding integrated nadir intensities were both compared to a model of the emission based on the Reactive Processes Ruling the Ozone Budget in the Stratosphere (REPROBUS) chemical transport model. The airglow intensities depend mostly on the solar zenith angle (both in model and data), and the model underestimates the observed emission by ∼15 %. This is confirmed with SCIAMACHY nadir-viewing measurements over the oceans: in such conditions, we have disentangled and retrieved the nadir O2* emission in spite of the moderate spectral resolving power (∼860) and found that the nadir SCIAMACHY intensities are mostly dictated by solar zenith angle (SZA) and are larger than the model intensities by a factor of ∼1.13. At a fixed SZA, the model airglow intensities show very little horizontal structure, in spite of ozone variations. It is shown that with the MicroCarb spectral resolution power (25 000) and signal-to-noise ratio (SNR), the contribution of the O2* emission at 1.27 µm to the observed spectral radiance in nadir viewing may be disentangled from the lower atmosphere/ground absorption signature with a great accuracy. Indeed, simulations with 4ARCTIC radiative transfer inversion tool have shown that the CO2 mixing ratio may be retrieved with the accuracy required for quantifying the CO2 natural sources and sinks (pressure-level error ≤1 hPa; XCO2 accuracy better than 0.4 ppmv) with the O2 1.27 µm band only as the air proxy (without the A band). As a result of these studies (at an intermediate phase), it was decided to include this band (B4) in the MicroCarb design, while keeping the O2 A band for reference (B1). Our approach is consistent with the approach of Sun et al. (2018), who also analysed the potential of the O2 1.27 µm band and concluded favourably for GHG monitoring from space. We advocate for the inclusion of this O2 band on other GHG monitoring future space missions, such as GOSAT-3 and EU/European Space Agency (ESA) CO2-M missions, for a better GHG retrieval.

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The use of the 1.27 µm O₂ absorption band for greenhouse gas monitoring from space and application to MicroCarb

et al. 2020

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“…It has also been observed in the stratospheres of the giant planets in a few cases (Figure 10). In particular, resonant fluorescence of methane has been observed at 3.3 μm in the upper stratosphere of Jupiter and Saturn (Drossart et al 1999); resonant fluorescence of CO has been observed on terrestrial planets (Gilli et al 2011;Marcq et al 2015), Uranus (Encrenaz et al 2004), Neptune (Fletcher et al 2010, Figure 10) and Titan (Lellouch et al 2003) at 4.7 μm. This mechanism has to be mentioned as it could take place in the upper atmospheres of exoplanets.…”

Section: Infrared Spectra Of (Exo)planetsmentioning

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From Solar System to Exoplanets: What can we learn from Planetary Spectroscopy?

Encrenaz¹

2022

Res. Astron. Astrophys.

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The purpose of this paper is to address the question: Using our knowledge of in- frared planetary spectroscopy, what can we learn about the atmospheres of the exoplanets? In a first part, a simplified classification of exoplanets, assuming thermochemical equilibrium, is presented, based on their masses and their equilibrium temperatures, in order to propose some possible estimations about their atmospheric composition. In the second part, infrared spectra of planets are discussed, in order to see what lessons can be drawn for exoplanetary spectroscopy. In the last part, we consider the Solar system as it would appear from a star located in the ecliptic plane. It first appears that the Solar system (except in a few specific cases) would not be seen as a multiple system, because, contrary to many exoplanetary sys- tems, the planets are too far from the Sun and the inclinations of their orbits with respect to the ecliptic plane are too high. Primary transit synthetic spectra of solar system planets are used to discuss the relative merits of transmission and direct emission spectroscopy for probing exoplanetary atmospheres.

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Three‐Dimensional Structures of Thermal Tides Simulated by a Venus GCM

et al. 2018

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Thermal tides in the Venus atmosphere are investigated by using a GCM named as AFES‐Venus. The three‐dimensional structures of wind and temperature associated with the thermal tides obtained in our model are fully examined and compared with observations. The result shows that the wind and temperature distributions of the thermal tides depend complexly on latitude and altitude in the cloud layer, mainly because they consist of vertically propagating and trapped modes with zonal wave numbers of 1–4, each of which predominates in different latitudes and altitudes under the influence of mid‐ and high‐latitude jets. A strong circulation between the subsolar and antisolar (SS‐AS) points, which is equivalent to a diurnal component of the thermal tides, is superposed on the superrotation. The vertical velocity of SS‐AS circulation is about 10 times larger than that of the zonal‐mean meridional circulation (ZMMC) in 60–70 km altitudes. It is suggested that the SS‐AS circulation could contribute to the material transport, and its upward motion might be related to the UV dark region observed in the subsolar and early afternoon regions in low latitudes. The terdiurnal and quaterdiurnal tides, which may be excited by the nonlinear interactions among the diurnal and semidiurnal tides in middle and high latitudes, are detected in the solar‐fixed Y‐shape structure formed in the vertical wind field in the upper cloud layer. The ZMMC is weak and has a complex structure in the cloud layer; the Hadley circulation is confined to latitudes equatorward of 30°, and the Ferrel‐like one appears in middle and high latitudes.

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Search for horizontal and vertical variations of CO in the day and night side lower mesosphere of Venus from CSHELL/IRTF 4.53μm observations

Cited by 30 publications

References 29 publications

The use of the 1.27 µm O₂ absorption band for greenhouse gas monitoring from space and application to MicroCarb

The use of the 1.27 µm O₂ absorption band for greenhouse gas monitoring from space and application to MicroCarb

From Solar System to Exoplanets: What can we learn from Planetary Spectroscopy?

Three‐Dimensional Structures of Thermal Tides Simulated by a Venus GCM

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Search for horizontal and vertical variations of CO in the day and night side lower mesosphere of Venus from CSHELL/IRTF 4.53μm observations

Cited by 30 publications

References 29 publications

The use of the 1.27 µm O2 absorption band for greenhouse gas monitoring from space and application to MicroCarb

The use of the 1.27 µm O2 absorption band for greenhouse gas monitoring from space and application to MicroCarb

From Solar System to Exoplanets: What can we learn from Planetary Spectroscopy?

Three‐Dimensional Structures of Thermal Tides Simulated by a Venus GCM

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Product

Resources

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The use of the 1.27 µm O₂ absorption band for greenhouse gas monitoring from space and application to MicroCarb

The use of the 1.27 µm O₂ absorption band for greenhouse gas monitoring from space and application to MicroCarb