Atomic and ionic calcium in the Earth's upper atmosphere

Granier, C.; Jegou, J. P.; Mégie, G.

doi:10.1029/jd094id07p09917

Cited by 28 publications

(28 citation statements)

References 15 publications

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“…3), we observed between 84 and 91 km altitude a typical narrow regular summer Ca layer, similar to the ones reported by Granier et al (1989), Alpers et al (1996), and Gerding et al (2000). Throughout the observation, its lower ledge ascended wavelike from 83 to 86 km.…”

Section: Observations Of Neutral and Ionized Sporadic Metal Layers: Fsupporting

confidence: 72%

“…For the location of Sao José dos Campos, Brasil (23 • S, 46 • W) Clemesha (1995) found the mean Na s height to be 2 km higher than the regular layer maximum. Case studies of direct comparisons of sporadic Ca and Ca + layers have been reported by two groups (Granier et al, 1989;Alpers et al, 1996). Both studies gave examples for simultaneous Ca s +Ca + s layers as well as for Ca + s without Ca s .…”

Section: Discussion Of the Observationsmentioning

confidence: 99%

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Sporadic Ca and Ca<sup>+</sup> layers at mid-latitudes: Simultaneous observations and implications for their formation

et al. 2001

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Abstract. We report on the observations of 188 sporadic layers of either Ca atoms and/or Ca ions that we have observed during 112 nights of lidar soundings of Ca, and 58 nights of Ca + soundings, at Kühlungsborn, Germany (54 • N, 12 • E). The Ca + soundings have been performed simultaneously and in a common volume with the Ca soundings by two separate lidars. Correlations between sporadic neutral and ionized metal layers are demonstrated through four case studies. A systematic study of the variations of occurrence of sporadic Ca and Ca + layers reveals that neutral and ionized Ca layers are not as closely correlated as expected earlier: (a) The altitude distribution shows the simultaneous occurrence of both sporadic Ca and Ca + layers to be most likely only in the narrow altitude range between 90 and 95 km. Above that region, in the lower thermosphere, the sporadic ion layers are much more frequent than atom layers. Below 90 km only very few sporadic layers have been observed; (b) The seasonal variation of sporadic Ca layers exhibits a minimum of occurrence in summer, while sporadic Ca + layers do not show a significant seasonal variation (only the dense Ca + layers appear to have a maximum in summer). At midlatitudes sporadic Ca layers are more frequent than sporadic layers of other atmospheric metals like Na or K. For the explanation of our observations new formation mechanisms are discussed.

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Section: Observations Of Neutral and Ionized Sporadic Metal Layers: Fsupporting

confidence: 72%

Section: Discussion Of the Observationsmentioning

confidence: 99%

Sporadic Ca and Ca<sup>+</sup> layers at mid-latitudes: Simultaneous observations and implications for their formation

et al. 2001

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“…They are produced at very high altitudes only (∼92 km) and should be indeed unobservable in the lunar umbra. They mention the detection of CaII signatures however, while it is also known that in the Earth atmosphere CaII ions are only present at high altitudes (Granier et al 1989). CaII is furthermore about 120 times fainter than NaI, thus the CaII detection (and not the NaI one) is quite a surprise.…”

Section: Previous Lunar Eclipse Studiesmentioning

confidence: 98%

The Earth as an extrasolar transiting planet

Vidal‐Madjar

Arnold

Ehrenreich

et al. 2010

A&A

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Context. An important goal within the quest for detecting an Earth-like extrasolar planet, will be to identify atmospheric gaseous bio-signatures. Aims. Observations of the light transmitted through the Earth's atmosphere, as for an extrasolar planet, will be the first important step for future comparisons. We have completed observations of the Earth during a lunar eclipse, a unique situation similar to that of a transiting planet. We aim at showing what species could be detected in its atmosphere at optical wavelengths, where a lot of photons are available in the masked stellar light. Methods. We present observations of the 2008 August 16 Moon eclipse performed with the SOPHIE spectrograph at the Observatoire de Haute-Provence (France). Locating the spectrograph's fibers in the penumbra of the eclipse, the Moon irradiance is then a mix of direct, unabsorbed Sun light and solar light that has passed through the Earth's atmosphere. This mixture essentially reproduces what is recorded during the transit of an extrasolar planet. Results. We report here the clear detection of several Earth atmospheric compounds in the transmission spectra, such as ozone, molecular oxygen, and neutral sodium as well as molecular nitrogen and oxygen through the Rayleigh signature. Moreover, we present a method that allows us to derive the thickness of the atmosphere versus the wavelength for penumbra eclipse observations. We quantitatively evaluate the altitude at which the atmosphere becomes transparent for important species like molecular oxygen and ozone, two species thought to be tightly linked to the presence of life. Conclusions. The molecular detections presented here are an encouraging first attempt, necessary to better prepare for the future of extremely-large telescopes and transiting Earth-like planets. Instruments like SOPHIE will be mandatory when characterizing the atmospheres of transiting Earth-like planets from the ground and searching for bio-marker signatures.

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“…Observations show that the Ca + layer is much more variable than the Ca layer (Gerding et al, 2000;Granier et al, 1989). Although there is reasonable agreement in the general shape of the Ca + layer, and the model captures the Ca + ion density at certain heights measured both by the lidar and the two rocket flights, overall the model appears to over-15 predict the Ca + density.…”

Section: Annual Mean Profiles Of Ca Speciesmentioning

confidence: 92%

“…the resonance lidar technique, and shown to peak around 90 km (Granier et al, 1985). Since then, a relatively small number of lidar studies of Ca and Ca + (which uniquely among the meteoric metal ions can be observed by ground-based lidar) have been performed (Alpers et al, 1996;Gerding et al, 2000;Granier et al, 1989;Qian and Gardner, 1995;Raizada et al, 2011;Raizada et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

A new model of meteoric calcium in the mesosphere and lower thermosphere

Plane¹,

Feng²,

Martı́n³

et al. 2018

Preprint

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Abstract. Meteoric ablation produces layers of metal atoms in the mesosphere and lower thermosphere (MLT). It has been known for more than 30 years that the Ca atom layer is depleted by over 2 orders of magnitude compared with Na, despite these elements having essentially the same elemental abundance in chondritic meteorites. In contrast, the Ca + ion abundance 15 is depleted by less than a factor of 10. To explain these observations, a large data-base of neutral and ion-molecule reaction kinetics of Ca species, measured over the past decade, was incorporated into the Whole Atmosphere Community Climate Model (WACCM). A new meteoric input function for Ca and Na, derived using a chemical ablation model that has been tested experimentally with a Meteoric Ablation Simulator, shows that Ca experiences significant differential ablation, by almost 1 order of magnitude, with respect to Na. WACCM-Ca simulates the seasonal Ca layer satisfactorily when compared with lidar 20 observations, but tends to overestimate Ca + measurements made by rocket mass spectrometry and lidar. A key finding is that CaOH and CaCO3 are very stable reservoir species because they are involved in essentially closed reaction cycles with O2 andO. This has been demonstrated experimentally for CaOH, and in this study for CaCO3 using electronic structure and statistical rate theory. Most of the neutral Ca is therefore locked in these reservoirs, enabling rapid loss through polymerization into meteoric smoke particles and explaining the extreme depletion of Ca. 25

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Atomic and ionic calcium in the Earth's upper atmosphere

Cited by 28 publications

References 15 publications

Sporadic Ca and Ca<sup>+</sup> layers at mid-latitudes: Simultaneous observations and implications for their formation

Sporadic Ca and Ca<sup>+</sup> layers at mid-latitudes: Simultaneous observations and implications for their formation

The Earth as an extrasolar transiting planet

A new model of meteoric calcium in the mesosphere and lower thermosphere

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Atomic and ionic calcium in the Earth's upper atmosphere

Cited by 28 publications

References 15 publications

Sporadic Ca and Ca&lt;sup&gt;+&lt;/sup&gt; layers at mid-latitudes: Simultaneous observations and implications for their formation

Sporadic Ca and Ca&lt;sup&gt;+&lt;/sup&gt; layers at mid-latitudes: Simultaneous observations and implications for their formation

The Earth as an extrasolar transiting planet

A new model of meteoric calcium in the mesosphere and lower thermosphere

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Product

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Sporadic Ca and Ca<sup>+</sup> layers at mid-latitudes: Simultaneous observations and implications for their formation

Sporadic Ca and Ca<sup>+</sup> layers at mid-latitudes: Simultaneous observations and implications for their formation