A large‐aperture sodium fluorescence lidar with very high resolution for mesopause dynamics and adaptive optics studies

Pfrommer, Thomas; Hickson, Paul; She, C. Y.

doi:10.1029/2009gl038802

Cited by 78 publications

(69 citation statements)

References 32 publications

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“…9. This is consistent with the observations of Mathews et al (1993), Pfrommer et al (2009) and Tsuda et al (2011). The peak density also varied in a similar way.…”

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

confidence: 81%

“…In fact, such discrete scattering regions can also be discerned from Fig. 1c of Pfrommer et al (2009), which indicates that multiple discrete scattering regions might be an inherent phenomenon of Na s layers, only concealed by the lower time resolution previously adopted. Interestingly, a number of discrete, localized, patchy scatterers have also been seen in sporadic E layers (Hysell et al, 2002(Hysell et al, , 2004, and multiple scattering bodies were found in the meteor observations, too (Mathews et al, 2010).…”

Section: Casementioning

confidence: 79%

“…Besides, multiple thin layers also existed, only too weak to be noticed easily, such as the one around 97 km from ∼ 04:50 LT until shutdown. Such thin layers were observed frequently by high time resolution lidar (Pfrommer et al, 2009). Figure 6 shows the detailed evolution of these peaks.…”

Section: Casementioning

confidence: 97%

“…Observations made with an 8 s time resolution (Liu and Yi, 2009) have shown that Na s layers typically consist of a series of density enhancement bursts and that Na s peak height often varies by several hundred meters on a timescale of ∼ 30 s. Large-aperture sodium lidar with very high resolution reveals that the sodium layer can be highly structured with multiple layers varying in density and altitude on timescales ranging from minutes to hours (Pfrommer et al, 2009). Sodium lidar measurements with 5 s time resolution reveal the occurrence of dramatic sodium density increases as well as short-period wavelike structure in Na s layers with periods of several minutes (Tsuda et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

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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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“…9. This is consistent with the observations of Mathews et al (1993), Pfrommer et al (2009) and Tsuda et al (2011). The peak density also varied in a similar way.…”

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

confidence: 81%

Section: Casementioning

confidence: 79%

Section: Casementioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Comparison of sporadic sodium layer characteristics observed at different time resolutions

et al. 2013

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“…Shorter periods are attributed either to dynamical or convective instabilities (Fritts et al, 1997). KH instabilities were also observed in the sodium layer using a sodium fluorescence lidar at midlatitudes in summer (Pfrommer et al, 2009). Power spectral densities of altitude series of sporadic sodium layers were retrieved down to a scale of seconds with a sodium lidar at high latitudes in wintertime by Tsuda et al (2011).…”

Section: N Kaifler Et Al: Small-scale Waves In Nlcmentioning

confidence: 99%

Quantification of waves in lidar observations of noctilucent clouds at scales from seconds to minutes

et al. 2013

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Abstract. We present small-scale structures and waves observed in noctilucent clouds (NLC) by lidar at an unprecedented temporal resolution of 30 s or less. The measurements were taken with the Rayleigh/Mie/Raman lidar at the ALO-MAR observatory in northern Norway (69 • N) in the years 2008-2011. We find multiple layer NLC in 7.9 % of the time for a brightness threshold of δ β = 12 × 10 −10 m −1 sr −1 . In comparison to 10 min averaged data, the 30 s dataset shows considerably more structure. For limited periods, quasimonochromatic waves in NLC altitude variations are common, in accord with ground-based NLC imagery. For the combined dataset, on the other hand, we do not find preferred periods but rather significant periods at all timescales observed (1 min to 1 h). Typical wave amplitudes in the layer vertical displacements are 0.2 km with maximum amplitudes up to 2.3 km. Average spectral slopes of temporal altitude and brightness variations are −2.01 ± 0.25 for centroid altitude, −1.41 ± 0.24 for peak brightness and −1.73 ± 0.25 for integrated brightness. Evaluating a new single-pulse detection system, we observe altitude variations of 70 s period and spectral slopes down to a scale of 10 s. We evaluate the suitability of NLC parameters as tracers for gravity waves.

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Modeling the implications of Kelvin‐Helmholtz instability dynamics for airglow observations

et al. 2014

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A companion paper describes high-resolution, ground-based imaging of apparent Kelvin-Helmholtz instabilities (KHI) observed in OH airglow at~87 km over the Andes Lidar Observatory at 30°S. Here we employ direct numerical simulations (DNSs) and large eddy simulations (LESs) of KHI at Richardson numbers from Ri = 0.05 to 0.20 and relatively high Reynolds numbers of Re~2500 to 10,000 to illustrate the dependence of primary and secondary KHI on these quantities for the purpose of quantifying KHI dynamics observed by ground-based airglow imagers. Our DNS and LES reveal significant variations of both primary and secondary KHI scales and amplitudes with varying Ri and Re. Lower Ri and higher Re yield stronger and deeper initial 2-D KH billows. Low Re for a given Ri either yield larger-scale 3-D secondary instabilities or suppress them altogether. Secondary instability scales decrease as Re increases for a given Ri. Corresponding variations in implied KHI airglow signatures include (1) stronger airglow intensity variations for larger KHI wavelengths and depths (higher Ri), (2) stronger 2-D and 3-D responses for the initial KHI shear layer displaced somewhat from the airglow layer, and (3) stronger 3-D responses for the lower Ri and intermediate Re yielding the larger secondary instability scales.

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A large‐aperture sodium fluorescence lidar with very high resolution for mesopause dynamics and adaptive optics studies

Cited by 78 publications

References 32 publications

Comparison of sporadic sodium layer characteristics observed at different time resolutions

Comparison of sporadic sodium layer characteristics observed at different time resolutions

Quantification of waves in lidar observations of noctilucent clouds at scales from seconds to minutes

Modeling the implications of Kelvin‐Helmholtz instability dynamics for airglow observations

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