The mesospheric metal layer topside: Examples of simultaneous metal observations

Höffner, J.; Friedman, J. S.

doi:10.1016/j.jastp.2005.06.010

Cited by 38 publications

(34 citation statements)

References 20 publications

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“…Noting a fact that there is no summer topside extension if all the profiles containing sporadic layers are excluded in the calculation of the mean layers, we believe that the summer topside extensions of the mean Na and Fe layers at 301N reflect the smoothed high-altitude Na s and Fe s layers occurring in summertime. This is consistent with the earlier observations of Höffner and Friedman (2005). Höffner and Friedman (2004) found for the first time that the mean K and Ca layers at 541N exhibited similar summer Fig.…”

Section: Overall Statistics and Discussionsupporting

confidence: 93%

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High-altitude sporadic metal atom layers observed with Na and Fe lidars at 30°N

Ma¹,

Yi²

2010

Journal of Atmospheric and Solar-Terrestrial Physics

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Section: Overall Statistics and Discussionsupporting

confidence: 93%

“…8). In an earlier study, Höffner and Friedman (2005) reported three cases that the extremely weak and broad sporadic metal layers occurred above 105 km in April, August and October at 541N.…”

Section: Case Study 2 (18-19 April 2007)mentioning

confidence: 95%

High-altitude sporadic metal atom layers observed with Na and Fe lidars at 30°N

Ma¹,

Yi²

2010

Journal of Atmospheric and Solar-Terrestrial Physics

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“…Hence, we suggest that the micrometeoroids, that are too small and slow to yield the ionized meteor signature (ionized trail and head-echo) observed by radars but have a large population, may be the primary source of the mesospheric metal atoms [18]. Recently, Höffner and Friedman [19,20] found that the topside layers above 110 km for different metal atoms have remarkably similar seasonal characteristics and suggested a direct link between ablating meteoroids and the topside metal layers.…”

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confidence: 77%

Preliminary lidar observations of Na meteor trails at Wuhan (30.5°N, 114.4°E), China

Xie

2010

Chin. Sci. Bull.

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Na lidar measurements of atom meteor trails with an integration period of 3.2 s were conducted at Wuhan (30.5°N, 114.4°E), China. A total of 125 Na meteor trail events were registered from 166 hours (16 nights) of lidar data. These Na trails show peak densities ranging from 4040 to 39170 cm −3 with a mean of 16430 cm −3 , while their occurrence altitudes vary from 77.2 to 111.6 km with a distribution centroid at 92.6 km. The upper edge of the Na trail altitude distribution resembles that of the altitude profile of the simultaneously observed mean Na layer. In particular, the trail altitude histogram maximum occurs around the mean Na layer peak. This is consistent with early lidar observations of K and Fe trails, which shows that meteoroids entering the atmosphere tend to yield more atom meteor trails detectable by ground-based lidars around the peak of the regular metal layers than elsewhere. It was found that the formation of the Na s layers was usually accompanied by a bunch of Na meteor trails, and that they occurred near the altitude of the Na s layer peak.lidar observations, meteoric trails, Na atom layer Citation:Xie Q H, Yi F.

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“…On the other hand, massive meteor trails have been observed by various radars (Briczinski et al, 2009;Ceplecha et al, 1998;Dyrud et al, 2011;Janches et al, 2001;Sugar et al, 2010;Zeng and Yi, 2011;Zhou and Perillat, 1998). Furthermore, there is some experimental evidence for a correlation between Na s and Es layer occurrence and meteor rates (Batista et al, 1989;Dou et al, 2010;Hansen and von Zahn, 1990;Hoeffner and Friedman, 2005;Höffner and Friedman, 2004), combined with the similar quasi-periodic oscillation and spatially localized scattering regions in Na s , Es and meteor trails, so that a possible role of meteor deposition in the formation of Na s layers should not be discarded. Sporadic sodium layers usually cover a height range of several kilometers and exhibit short-period oscillations, and single meteoroids (Clemesha et al, 1978) cannot explain these two characteristics.…”

Section: The Quasi-periodic Oscillation Phenomenon In Na S Layersmentioning

confidence: 99%

Comparison of sporadic sodium layer characteristics observed at different time resolutions

et al. 2013

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Abstract. Sporadic sodium (Na s ) layers, occurring in roughly the same height range as ionospheric sporadic-E layers, were first detected by lidar some 30 yr ago. Na s layers have a typical thickness of a few hundred meters to a few km, with peak atom concentrations several times that of the background layer. Despite a great deal of excellent work over the past decades, the source of Na s layers is still not altogether clear, partly as a result of our incomplete knowledge of Na s layer characteristics. In this paper we concentrate on some typical case studies chosen from the ∼ 127 h of sporadic sodium layer observations made at a time resolution of 1.5 s at Yanqing (115.97 • E, 40.47 • N), Beijing, China. This is a much better time resolution than what has been employed in most earlier measurements. The results show that the Na s layer peak heights are dispersed at slightly different although adjacent heights. When averaged over several minutes, as has been the case with most earlier measurements, the height scatter results in an apparent layer thickness of a few km. We conclude, therefore, that these dispersed peaks at different but adjacent heights constitute the 5 min Na s layer. Similar to the observations of sporadic-E-ion (Es) layers and meteor rate, we observe quasi-periodic fluctuations on a timescale on the order of several minutes in the peak height and the peak density of sporadic layers, which is a universal feature but concealed by the lower temporal resolution previously adopted. Spatially localized multiple scatterers and multiple thin layers with similar apparent movement in Na s layers are also found. We discuss the possible formation mechanism by the direct deposition of large swarms of micrometeoroids and demonstrate a typical example of meteor trails evolving into a Na s layer, which suggests that this mechanism might indeed occur.

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The mesospheric metal layer topside: Examples of simultaneous metal observations

Cited by 38 publications

References 20 publications

High-altitude sporadic metal atom layers observed with Na and Fe lidars at 30°N

High-altitude sporadic metal atom layers observed with Na and Fe lidars at 30°N

Preliminary lidar observations of Na meteor trails at Wuhan (30.5°N, 114.4°E), China

Comparison of sporadic sodium layer characteristics observed at different time resolutions

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