The diurnal variation of atmospheric sodium

Clemesha, B. R.; Simonich, D. M.; Batista, P. P.; Kirchhoff, V. W. J. H.

doi:10.1029/ja087ia01p00181

Cited by 64 publications

(51 citation statements)

References 13 publications

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“…4c, there is now less than 0.5 km change in the peak height between midnight and midday. In contrast, the centroid height of the layer decreases from 92.5 km to 91.0 km in daytime, which is in good accord with observations (Clemesha et al, 1982). This decrease arises largely because during daytime there is additional ionization of Na on the topside, as well as photolysis of NaHCO 3 on the bottomside.…”

Section: Meteoroid Ablation Modelsupporting

confidence: 80%

“…This shows that the Na layer always peaks below 90 km, that the peak moves 2 km lower in daytime, and that the underside of the layer has a scale height less than 1 km. These model predictions are not in accord with lidar observations of the diurnal behaviour of the layer (Clemesha et al, 1982;States and Gardner, 2000). However, if removal of NaHCO 3 by dimerization is now switched on in the model, Fig.…”

Section: Meteoroid Ablation Modelcontrasting

confidence: 35%

“…2.4, this would cause a large increase in Na below 90 km during the day, arising from NaHCO 3 photolysis. Because such an increase is not in fact observed (Clemesha et al, 1982;States and Gardner, 2000), the most likely explanation is that NaHCO 3 is permanently removed in the 75 to 85 km region. In the new model to be described here, this removal occurs through the polymerization of NaHCO 3 into dimers, and also by the uptake of sodium species onto meteoric smoke particles (Hunten et al, 1980;Kalashnikova et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

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A time-resolved model of the mesospheric Na layer: constraints on the meteor input function

2004

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Abstract.A time-resolved model of the Na layer in the mesosphere/lower thermosphere region is described, where the continuity equations for the major sodium species Na, Na + and NaHCO 3 are solved explicity, and the other shortlived species are treated in steady-state. It is shown that the diurnal variation of the Na layer can only be modelled satisfactorily if sodium species are permanently removed below about 85 km, both through the dimerization of NaHCO 3 and the uptake of sodium species on meteoric smoke particles that are assumed to have formed from the recondensation of vaporized meteoroids. When the sensitivity of the Na layer to the meteoroid input function is considered, an inconsistent picture emerges. The ratio of the column abundance of Na + to Na is shown to increase strongly with the average meteoroid velocity, because the Na is injected at higher altitudes. Comparison with a limited set of Na + measurements indicates that the average meteoroid velocity is probably less than about 25 km s −1 , in agreement with velocity estimates from conventional meteor radars, and considerably slower than recent observations made by wide aperture incoherent scatter radars. The Na column abundance is shown to be very sensitive to the meteoroid mass input rate, and to the rate of vertical transport by eddy diffusion. Although the magnitude of the eddy diffusion coefficient in the 80-90 km region is uncertain, there is a consensus between recent models using parameterisations of gravity wave momentum deposition that the average value is less than 3×10 5 cm 2 s −1 . This requires that the global meteoric mass input rate is less than about 20 t d −1 , which is closest to estimates from incoherent scatter radar observations. Finally, the diurnal variation in the meteoroid input rate only slight perturbs the Na layer, because the residence time of Na in the layer is several days, and diurnal effects are effectively averaged out.

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Section: Meteoroid Ablation Modelsupporting

confidence: 80%

Section: Meteoroid Ablation Modelcontrasting

confidence: 35%

Section: Introductionmentioning

confidence: 99%

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A time-resolved model of the mesospheric Na layer: constraints on the meteor input function

2004

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“…5c) with lidar measurements made in Brazil at this latitude. These measurements show a predominantly semi-diurnal variation with maxima at 06:00 and 18:00 LT (Clemesha et al, 1982). However, these lidar observations were restricted to winter, whereas the satellite measurements exhibit the relatively modest diurnal variation at 23 • S during spring and autumn, and in fact show essentially no diurnal variation at the summer solstice (January).…”

Section: Diurnal Variation In the Equatorial Regionmentioning

confidence: 90%

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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“…The distribution of our measurements compared to any tidal variation happened to be rather even, so that any tidal variation would change the mean and median values only by a small amount. We see that the Na column density is subject to variation, but according to Granier and Mégie (1982) and Clemesha et al (1982) the Na layer does not exhibit a significant diurnal variation. Plane (2004) has shown that the lack of a diurnal variation of the Na layer can be caused by the uptake of NaHCO 3 (the major Na reservoir species below about 85 km) on meteoric smoke particles.…”

Section: Sodium Layermentioning

confidence: 95%

Development of the mesospheric Na layer at 69° N during the Geminids meteor shower 2010

et al. 2013

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Abstract. The ECOMA sounding rocket campaign in 2010 was performed to investigate the charge state and number density of meteoric smoke particles during the Geminids meteor shower in December 2010. The ALOMAR Na lidar contributed to the campaign with measurements of sodium number density, temperature and line-of-sight wind between 80 and 110 km altitude over Andøya in northern Norway. This paper investigates a possible connection between the Geminids meteor shower and the mesospheric sodium layer. We compare with data from a meteor radar and from a rocketborne in situ particle instrument on three days. Our main result is that the sodium column density is smaller during the Geminids meteor shower than the winter average at the same latitude. Moreover, during two of the three years considered, the sodium column density decreased steadily during these three weeks of the year. Both the observed decrease of Na column density by 30 % and of meteoric smoke particle column density correlate well with a corresponding decrease of sporadic meteor echoes. We found no correlation between Geminids meteor flux rates and sodium column density, nor between sporadic meteors and Na column density (R = 0.25). In general, we found the Na column density to be at very low values for winter, between 1.8 and 2.6 × 10 13 m −2 . We detected two meteor trails containing sodium, on 13 December 2010 at 87.1 km and on 19 December 2010 at 84 km. From these meteor trails, we estimate a global meteoric Na flux of 121 kg d −1 and a global total meteoric influx of 20.2 t d −1 .

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The diurnal variation of atmospheric sodium

Cited by 64 publications

References 13 publications

A time-resolved model of the mesospheric Na layer: constraints on the meteor input function

A time-resolved model of the mesospheric Na layer: constraints on the meteor input function

Satellite measurements of the global mesospheric sodium layer

Development of the mesospheric Na layer at 69° N during the Geminids meteor shower 2010

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