Limb observations of the ultraviolet nitric oxide nightglow with SPICAV on board Venus Express

Gérard, Jean‐Claude; Cox, Cédric; Saglam, Adem; Bertaux, Jean-Loup; Villard, Eric; Nehmé, C.

doi:10.1029/2008je003078

Cited by 62 publications

(75 citation statements)

References 31 publications

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“…4 shows spectra from orbit 0516, in which the C(0) 3 A(0) band appears distinctly at somewhat lower altitudes than in orbit 0724. The inferred peak intensity in the UV is 108 kR, Ϸ4 times less than previously reported for this very orbit at an unspecified location north of the equator (27). Factors such as the systematic averaging of individual spectra and the inevitably crude estimate of the C(0) 3 A(0) band intensities at our instrumental resolution may also contribute to the disparity between the SPICAV and VIRTIS findings.…”

Section: Detection Of the Near-infrared Nitric Oxide Nightglowcontrasting

confidence: 48%

“…2, which translate, according to our earlier discussion, into limb intensities of 7.9-63 kR for the C(0)ϪA(0) band. At its peak, this implies a total intensity for the middle-UV nitric oxide nightglow of Ϸ190 kR, significantly larger than the average value inferred by SPICAV but smaller than the 440 kR that SPICAV observed in orbit 0516 (27). It is clear that session 072402 is an episodic event of highly enhanced nightglow similar to those identified by SPICAV.…”

Section: Detection Of the Near-infrared Nitric Oxide Nightglowmentioning

confidence: 72%

“…1. Normalized SPICAV spectrum of the vЈ ϭ 0 progressions of the nitric oxide C 3 X and A 3 X nightglow on Venus (27) as digitized by us, and our best fit with a synthetic spectrum produced with LIFBASE (28) at a rotational temperature of 175 K. Both spectra are nearly undistinguishable on the scale of the plot. For the fitting, the observational spectrum is split near 220 nm, so that the 2 resulting partial spectra are allowed to shift in wavelength independently.…”

Section: Detection Of the Near-infrared Nitric Oxide Nightglowmentioning

confidence: 99%

“…Our analysis of the spectrum of both UV progressions published recently (27) provides a new observational determination of the branching ratio. We digitized the published spectrum obtained by the spectroscopy for investigation of characteristics of the atmosphere of venus (SPICAV) instrument on Venus Express and fit it with synthetic spectra produced with the simulation software LIFBASE (28).…”

Section: Nitric Oxide Deactivation Branching Ratiomentioning

confidence: 99%

“…A recent work (27) reported observations by SPICAV of the 2 UV progressions from a few selected orbits between January and September 2007 at 6.1°N to 71.8°N latitude. The observed vertical profiles of the line-of-sight integrated intensities for the 2 UV nightglow emissions show large variations in the altitude at which the emission peaks, 95Ϫ132 km.…”

Section: Near-infrared Nitric Oxide Bandmentioning

confidence: 99%

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The near-infrared nitric oxide nightglow in the upper atmosphere of Venus

Muñoz

Mills

Piccioni

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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The v ‫؍‬ 0 progressions of the C 3 X and A 3 X band systems of nitric oxide dominate the middle-UV spectrum of the night-time upper atmospheres of the Earth, Mars, and Venus. The C(0) 3 A(0)؉h radiative transition at 1.224 m, the only channel effectively populating the A(0) level, must therefore occur also. There have been, however, no reported detections of the C(0) 3 A(0) band in the atmospheres of these or any other planets. We analyzed all available near-infrared limb observations of the darkside atmosphere of Venus by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) instrument on the Venus Express spacecraft and found 2 unambiguous detections of this band at equatorial latitudes that seem to be associated with episodic events of highly enhanced nightglow emission. The discovery of the C(0) 3 A(0) band means observations in the 1.2-1.3 m region, which also contains the a(0) 3 X(0) emission band of molecular oxygen, can provide a wealth of information on the high-altitude chemistry and dynamics of the Venusian atmosphere.T he luminescence that results from exothermic chemical reactions between the constituents of a planetary atmosphere is customarily termed the night airglow or, simply, the nightglow (1). Although possibly present all day long, it appears most distinctly at night when the other processes of atomic and molecular excitation that depend directly on the action of the Sun are not at play and the diffuse radiation of solar light is at its minimum. The nightglow may originate from various, possibly minor, atmospheric constituents and provides insight into the chemistry, composition, temperature and energy balance of the atmosphere of a planet.The C 2 ⌸ 3 X 2 ⌸ and A 2 ⌺ ϩ 3 X 2 ⌸ band systems of nitric oxide (often referred to as the ␦ and ␥ bands, respectively) have long been known in the upper-atmospheric nightglow of the Earth (2, 3) and Venus (4, 5). More recently, they have also been reported in the atmosphere of Mars (6). A common structure, caused by the vЈ ϭ 0 progression of the aforementioned systems, characterizes the night-time middle-UV spectrum of all 3 planets. Separately and in combination with other nightglow emissions, observations of the nitric oxide nightglow have been used to infer details of the odd-nitrogen chemistry and dynamics in the emitting atmospheres.In the dayglow, resonance scattering of solar photons from ground-state nitric oxide gives rise to additional A 3 X (vЈ Ն 0) bands that have been observed on the sunlit side of the Earth (7) but that remain undetected in the atmospheres of Mars and Venus. On Mars, and expectedly also on Venus, the emission of the a 3 ⌸ 3 X 1 ⌺ system of carbon monoxide is likely to mask the nitric oxide A 3 X dayglow (8). The fluorescence efficiency of the C state is low for v ϭ 0 and negligible for vϾ0, presumably due to rapid predissociation (9-12). Day-time observations of the terrestrial atmosphere have found weak C 3 X (vЈ ϭ 0) bands, which have been attributed to resonance scattering (13-15), although there are significa...

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Section: Detection Of the Near-infrared Nitric Oxide Nightglowcontrasting

confidence: 48%

Section: Detection Of the Near-infrared Nitric Oxide Nightglowmentioning

confidence: 72%

Section: Detection Of the Near-infrared Nitric Oxide Nightglowmentioning

confidence: 99%

Section: Nitric Oxide Deactivation Branching Ratiomentioning

confidence: 99%

Section: Near-infrared Nitric Oxide Bandmentioning

confidence: 99%

See 3 more Smart Citations

The near-infrared nitric oxide nightglow in the upper atmosphere of Venus

Muñoz

Mills

Piccioni

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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Nitric oxide nightglow and Martian mesospheric circulation from MAVEN/IUVS observations and LMD‐MGCM predictions

et al. 2017

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We report results from a study of nitric oxide nightglow over the northern hemisphere of Mars during winter, the southern hemisphere during fall equinox, and equatorial latitudes during summer in the northern hemisphere based on observations of the δ and γ bands between 190 and 270 nm by the Imaging UltraViolet Spectrograph (IUVS) on the Mars Atmosphere and Volatile EvolutioN mission (MAVEN) spacecraft. The emission reveals recombination of N and O atoms dissociated on the dayside of Mars and transported to the nightside. We characterize the brightness (from 0.2 to 30 kR) and altitude (from 40 to 115 km) of the NO nightglow layer, as well as its topside scale height (mean of 11 km). We show the possible impact of atmospheric waves forcing longitudinal variability, associated with an increased brightness by a factor of 3 in the 140–200° longitude region in the northern hemisphere winter and in the −102° to −48° longitude region at summer. Such impact to the NO nightglow at Mars was not seen before. Quantitative comparison with calculations of the LMD‐MGCM (Laboratoire de Météorologie Dynamique‐Mars Global Climate Model) suggests that the model globally reproduces the trends of the NO nightglow emission and its seasonal variation and also indicates large discrepancies (up to a factor 50 fainter in the model) in northern winter at low to middle latitudes. This suggests that the predicted transport is too efficient toward the night winter pole in the thermosphere by ∼20° latitude north.

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Variability of the nitric oxide nightglow at Venus during solar minimum

2016

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We present results from a NO airglow inversion method based on Venus Express data acquired from 2006 to 2010, during the last solar minimum period. We retrieve an altitude of 114 ± 10 km for the emission peak of the NO layer, with an associated scale height of 20 ± 10 km and an average limb brightness of 59.3 kR with a standard deviation of 63 kR. The inversion method allows for the quantification of the horizontal homogeneity of the NO layer. Images of the SPICAV field of view show a great variability of airglow morphologies, with NO layers that can be horizontally homogenous and continuous over distances exceeding 100 km, as well as sporadic patches of NO on a smaller horizontal scale. Frequent secondary emissions seen at lower tangent altitudes are the signatures of the complex dynamics of the upper Venusian atmosphere.

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Limb observations of the ultraviolet nitric oxide nightglow with SPICAV on board Venus Express

Cited by 62 publications

References 31 publications

The near-infrared nitric oxide nightglow in the upper atmosphere of Venus

The near-infrared nitric oxide nightglow in the upper atmosphere of Venus

Nitric oxide nightglow and Martian mesospheric circulation from MAVEN/IUVS observations and LMD‐MGCM predictions

Variability of the nitric oxide nightglow at Venus during solar minimum

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