Daytime Laser Radar Measurements of the Atmospheric Sodium Layer

Gibson, A.J.; Sandford, M. C. W.

doi:10.1038/239509a0

Cited by 60 publications

(28 citation statements)

References 15 publications

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“…Indeed, a limited number of GOMOS measurements were made over the whole range of LT, from which the diurnal behaviour of the Na layer could be examined (Fussen et al, 2004). The data showed very little change in the layer at 06:00, 12:00 and 18:00 LT, and then a large decrease, by ∼40% between 70 and 90 km, at 24:00 LT. Strangely, such diurnal behaviour has not been observed by lidars located over a range of latitudes (Gibson and Sandford, 1972;Kirchhoff and Clemesha, 1983;States and Gardner, 1999;She et al, 2000). In conclusion, the GOMOS results are not in accord with either the OSIRIS measurements or ground-based lidars, but it is unclear why this is the case.…”

Section: Global Latitudinal and Seasonal Variationscontrasting

confidence: 45%

“…Lidar provided many advantages over photometers. Firstly, by active excitation of the atmospheric Na, observations could be performed over a full diurnal cycle: initially, night-time measurements were performed (Gibson and Sandford, 1971), but modified receivers to exclude scattered sunlight then enabled daytime measurements to be made (Gibson and Sandford, 1972). These measurements quickly showed that the apparent enhancement of the Na layer during daytime, reported from photometric measurements of the dayglow (Blamont and Donahue, 1961), was not correct.…”

Section: Introductionmentioning

confidence: 99%

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Satellite measurements of the global mesospheric sodium layer

et al. 2007

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Abstract. Optimal estimation theory is used to retrieve the absolute Na density profiles in the mesosphere/lower thermosphere from limb-scanning measurements of the Na radiance at 589 nm in the dayglow. Two years of observations (2003 and 2004), recorded by the OSIRIS spectrometer on the Odin satellite, have been analysed to yield the seasonal and latitudinal variation of the Na layer column abundance, peak height, and peak width. The layer shows little seasonal variation at low latitudes, but the winter/summer ratio increases from a factor of ∼3 at mid-latitudes to ∼10 in the polar regions. Comparison of the measurements made at about 06:00 and 18:00 LT shows little diurnal variation in the layer, apart from the equatorial region where, during the equinoxes, there is a two-fold increase in Na density below 94 km between morning and evening. This is most likely caused by the strong downward wind produced by the diurnal tide between ∼02:00 and 10:00 LT. The dramatic removal of Na below 85 km at latitudes above 50 • during summer is explained by the uptake of sodium species on the ice surfaces of polar mesospheric clouds, which were simultaneously observed by the Odin satellite.

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Section: Global Latitudinal and Seasonal Variationscontrasting

confidence: 45%

Section: Introductionmentioning

confidence: 99%

Satellite measurements of the global mesospheric sodium layer

et al. 2007

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“…A series of twentyfour-hour observations of the atmospheric sodium layer made at S. José dos Campos confiruí the conclusion of Gibson and Sandford (1972) that there is no significant day-night variation in the total abundance of atmospheric sodium.…”

Section: Discussionmentioning

confidence: 99%

“…The only daytinie data published so far is that of Gibson and Sandford, 1972, who Chanin and Gautail (1975) have shown that the large diurna] increase in sodiuni derived froni the dayglow results could at least partly result from an inadequate consideration of the effects of the earth's albedo. Gibson and Sandford (1972) presented only one profile of the daytime distribution of sodium, and did not discuss the variation of this distribution over a 24-hour period. The purpose of this paper is to present the results of 24-hour nieasurernents made over a period of 10 days iii May 1981 at So José dos Campos (23°S, 46 0 W), and to discuss the diurna] variation revealed by these observations.…”

Section: Introductionmentioning

confidence: 99%

The diurnal variation of atmospheric sodium

Clemesha¹,

Simonich²,

Batista³

et al. 1982

J. Geophys. Res.

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Continuous measurements of the vertical distribution of atmospheric sodium, made over a number of complete diurnal cycles, show the existence of strong semidiurnal oscillations in total abundance and height. The amplitude of the abundance variation, about 15% of the mean, is about twice that predicted for the 2,2 mode of the semidiurnal tide, and its phase, with maxima at 0400 and 1400 LT, is in good agreement with tidal theory. The vertical oscillation, with an amplitude of 2 km at a height of 100 km, is about 3 times the expected amplitude, and the measured vertical wavelength of 38 km is in good agreement with theory, although the phase is not. A strong diurnal oscillation, observed only at heights below 82 km, is interpreted as being the result of photochemical reactions between sodium and other atmospheric constituents. The lack of any appreciable 24‐hour component in the total abundance variation implies either a residence time for total sodium of more than 3 days, or source and sink functions whose diurnal variations, unless identical, are very small.

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“…The neutral/ionic forms of sodium constitute the mesospheric sodium layer that typically extends from 80 to 110 km in altitude and peaks in concentration at around 90 km. Since the discovery of Na layer in the late 1930s, several investigators have studied the origin and variation of this layer and the Na airglow originated therein (Blamont and Donahue 1961;Gibson and Sandford 1972;Kirchhoff and Clemesha 1983;Zahn et al 1988;Clemesha et al 1995;She et al 2000;Fan et al 2007;Kumar 2007;Sarkhel et al 2009). However, all these investigations were confined to either the night-time or satellite-based daytime studies.…”

Section: Introductionmentioning

confidence: 99%

Highly varying daytime sodium airglow emissions over an equatorial station: a case study based on the measurements using a grating monochromator

et al. 2014

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A case study is performed to investigate the probable reasons behind substantial daytime sodium (Na) D 1 airglow intensity (589.6 nm) variations measured using a ground-based monochromator during the three near consecutive days of February 2007 from Trivandrum (8.5°N, 77°E), India. The roles of both the resonance fluorescence and the chemistry have been considered in this study. It appears that fluorescence plays only a minor role towards the observed five to nine times of large intensity variations among these days. From investigations on the role of chemistry, it seems that through the Chapman chemical scheme, Na abundance contribute favorably, while the O 3 concentrations and the ambient temperature do not play any role as such for the observed intensity variations. From further investigations, it transpires that because of pressure differences (approximately 0.0002 to 0.0003 hPa/day) in the emitting altitude region among these days, the variations in collisional quenching of excited NaO * (A 2 Σ + ) (first excited electronic state of NaO that produces D line) contribute considerably towards the observed intensity variations. From consideration of all the possible factors, it appears that whereas resonance fluorescence plays only a minor role, chemistry has contributed to greater extent towards the observed significant intensity differences among these days.

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Daytime Laser Radar Measurements of the Atmospheric Sodium Layer

Cited by 60 publications

References 15 publications

Satellite measurements of the global mesospheric sodium layer

Satellite measurements of the global mesospheric sodium layer

The diurnal variation of atmospheric sodium

Highly varying daytime sodium airglow emissions over an equatorial station: a case study based on the measurements using a grating monochromator

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