Radar and optical observations of mesospheric wave activity during the lunar eclipse of 6 July 1982

Adams, G. W.; Peterson, A. W.; Brosnahan, J. W.; Neuschaefer, J. W.

doi:10.1016/0021-9169(88)90003-7

Cited by 12 publications

(9 citation statements)

References 20 publications

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“…Considering this, wave (I) propagates with a phase velocity of 4.9 ± 0.6 m s −1 and wave (II) with 34.5 ± 9.3 m s −1 . We speculate that the small wavelength, short lifetime and perpendicular direction of propagation may indicate a ripple structure as defined by Adams et al (1988) and Taylor and Hapgood (1990). They are distinguished from larger-scale structures termed as bands.…”

Section: Resultsmentioning

confidence: 90%

A fast SWIR imager for observations of transient features in OH airglow

et al. 2016

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Section: Resultsmentioning

confidence: 90%

A fast SWIR imager for observations of transient features in OH airglow

et al. 2016

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“…Peterson, 1979). Ripples are spatially limited wave structures with a short lifetime (Adams et al, 1988) and are caused by atmospheric instabilities (Taylor and Hapgood, 1990). As the 550 m wave packet does not form within the FOV, its lifetime cannot be estimated from our data.…”

Section: Discussionmentioning

confidence: 90%

High-resolution observations of small-scale gravity waves and turbulence features in the OH airglow layer

et al. 2016

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A new version of the Fast Airglow Imager (FAIM) for the detection of atmospheric waves in the OH airglow layer has been set up at the German Remote Sensing Data Center (DFD) of the German Aerospace Center (DLR) at Oberpfaffenhofen (48.09 • N, 11.28 • E), Germany. The spatial resolution of the instrument is 17 m pixel −1 in zenith direction with a field of view (FOV) of 11.1 km × 9.0 km at the OH layer height of ca. 87 km. Since November 2015, the system has been in operation in two different setups (zenith angles 46 and 0 • ) with a temporal resolution of 2.5 to 2.8 s.In a first case study we present observations of two small wave-like features that might be attributed to gravity wave instabilities. In order to spectrally analyse harmonic structures even on small spatial scales down to 550 m horizontal wavelength, we made use of the maximum entropy method (MEM) since this method exhibits an excellent wavelength resolution. MEM further allows analysing relatively short data series, which considerably helps to reduce problems such as stationarity of the underlying data series from a statistical point of view. We present an observation of the subsequent decay of well-organized wave fronts into eddies, which we tentatively interpret in terms of an indication for the onset of turbulence.Another remarkable event which demonstrates the technical capabilities of the instrument was observed during the night of 4-5 April 2016. It reveals the disintegration of a rather homogenous brightness variation into several filaments moving in different directions and with different speeds. It resembles the formation of a vortex with a horizontal axis of rotation likely related to a vertical wind shear. This case shows a notable similarity to what is expected from theoretical modelling of Kelvin-Helmholtz instabilities (KHIs).The comparatively high spatial resolution of the presented new version of the FAIM provides new insights into the structure of atmospheric wave instability and turbulent processes. Infrared imaging of wave dynamics on the subkilometre scale in the airglow layer supports the findings of theoretical simulations and modellings.

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“…These data cover more than 300 nights of OH airglow observations, all made on clear, moonless nights, out of which there are 105 nights that show ripple events. The ripple selected for this statistical study usually contains a limited number of crests (typically 3–10) and horizontal wavelengths less than 15 km and lifetimes less than 45 min [ Peterson and Adams , ; Adams et al ., ]. Among these 105 nights we select about 300 short‐period ripples to study their seasonal variations and characteristics in section 3.1.…”

Section: Resultsmentioning

confidence: 99%

“…The ripples, which were first identified by Peterson and Kieffaber [] in OH airglow images, are the small‐scale wavelike patterns with bright and dark areas perturbing the airglow emission. These structures typically contain 3–10 wavecrests with horizontal wavelength of 5–15 km and lifetime of a few minutes up to 45 min [ Peterson and Adams , ; Adams et al ., ] and have been extensively investigated in the literature [ Taylor and Hapgood , ; Taylor et al ., , ; Hecht et al ., , ; Hecht , ; F. Li et al ., ; T. Li et al ., ; Hecht et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Characteristics of ripple structures revealed in OH airglow images

Dou

et al. 2017

JGR Space Physics

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Small‐scale ripple structures observed in OH airglow images are most likely induced by either dynamic instability due to large wind shear or convective instability due to superadiabatic lapse rate. Using the data set taken in the mesopause region with an OH all‐sky imager at Yucca Ridge Field Station, Colorado (40.7°N, 104.9°W), from September 2003 to December 2005, we study the characteristics and seasonal variations of ripple structures. By analyzing the simultaneous background wind and temperature observed by the nearby sodium temperature/wind lidar at Fort Collins, Colorado (40.6°N, 105°W), and a nearby medium‐frequency radar at Platteville, Colorado (40.2°N, 105.8°W), we are able to statistically study the possible relation between ripples and the background atmosphere conditions. Characteristics and seasonal variations of ripples are presented in detail in this study. The occurrence frequency of ripples exhibits clear seasonal variability, with peak in autumn. The occurrence of ripples shows a local time dependence, which is most likely associated with the solar tides. The lifetime and spatial scale of these ripples are typically 5–20 min and 5–10 km, respectively, and most of the ripples move preferentially either southward or northward. However, more than half of the observed ripples do not advect with background flow; they have higher Richardson numbers than those ripples that advect with background flow. It is possible that they are not instability features but wave structures that are hard to be distinguished from the real instability features.

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Radar and optical observations of mesospheric wave activity during the lunar eclipse of 6 July 1982

Cited by 12 publications

References 20 publications

A fast SWIR imager for observations of transient features in OH airglow

A fast SWIR imager for observations of transient features in OH airglow

High-resolution observations of small-scale gravity waves and turbulence features in the OH airglow layer

Characteristics of ripple structures revealed in OH airglow images

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