Mesospheric gravity wave imaging at a subauroral site: First results from Millstone Hill

Smith, S. M.; Mendillo, M.; Baumgardner, Jeffrey; Clark, Ronald

doi:10.1029/1999ja000343

Cited by 55 publications

(55 citation statements)

References 56 publications

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“…The observed horizontal wavelengths, phase speeds, and periodicities are quite consistent with short-period measurements from mid-and low latitude (Swenson and Mende, 1994;Taylor et al, 1995b;Wu and Killeen, 1996;Taylor et al, 1997;Nakamura et al, 1999;Walterscheid et al, 1999;Smith et al, 2000;Hecht et al, 2001a,b;Ejiri et al, 2003;Medeiros et al, 2003;Nakamura et al, 2003;Pautet et al, 2005). However, the observed phase speeds are all relatively high (∼40-70 m/s) and are therefore not thought to be associated with orographic wave forcing.…”

Section: Discussionsupporting

confidence: 68%

“…A second wave event is also evident in these images entering the field of view from the right side. Similar morphology wave patterns associated with short-period gravity wave propagating through the MLT region have been reported from numerous sites at mid-and low latitudes (Swenson and Mende, 1994;Taylor et al, 1995b;Wu and Killeen, 1996;Taylor et al, 1997;Nakamura et al, 1999;Walterscheid et al, 1999;Smith et al, 2000;Hecht et al, 2001b;Medeiros et al, 2003;Nakamura et al, 2003;Ejiri et al, 2003;Brown et al, 2004;Pautet et al, 2005). Also evident in the bottom left of the Na image is a Super Loki falling sphere launch providing wind profile measurements in addition to the dual meteor MLT radar data measurements.…”

Section: Observations and Analysismentioning

confidence: 64%

“…significantly larger than the airglow emission layer depths). Measurements have been primarily made at mid-and low latitudes and have revealed a rich spectrum of waves (Swenson and Mende, 1994;Taylor et al, 1995b;Wu and Killeen, 1996;Taylor et al, 1997;Nakamura et al, 1999;Walterscheid et al, 1999;Smith et al, 2000;Hecht et al, 2001a,b;Ejiri et al, 2003;Medeiros et al, 2003;Nakamura et al, 2003;Brown et al, 2004;Pautet et al, 2005). These waves usually exhibit relatively high phase speeds (typically a few ten's of meters per second) and are able to penetrate rapidly (few hours) from their tropospheric source regions into the MLT where they saturate and break, depositing significant amounts of momentum (Fritts and Alexander, 2003, and references therein).…”

Section: Introductionmentioning

confidence: 99%

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Propagation of short-period gravity waves at high-latitudes during the MaCWAVE winter campaign

et al. 2006

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Abstract. As part of the MaCWAVE (Mountain and Convective Waves Ascending Vertically) winter campaign an allsky monochromatic CCD imager has been used to investigate the properties of short-period mesospheric gravity waves at high northern latitudes. Sequential measurements of several nightglow emissions were made from Esrange, Sweden, during a limited period from 27-31 January 2003. Coincident wind measurements over the altitude range (∼80-100 km) using two meteor radar systems located at Esrange and Andenes have been used to perform a novel investigation of the intrinsic properties of five distinct wave events observed during this period. Additional lidar and MSIS model temperature data have been used to investigate their nature (i.e. freely propagating or ducted). Four of these extensive wave events were found to be freely propagating with potential source regions to the north of Scandinavia. No evidence was found for strong orographic forcing by short-period waves in the airglow emission layers. The fifth event was most unusual exhibiting an extensive, but much smaller and variable wavelength pattern that appeared to be embedded in the background wind field. Coincident wind measurements indicated the presence of a strong shear suggesting this event was probably due to a large-scale Kelvin-Helmholtz instability.

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Section: Discussionsupporting

confidence: 68%

Section: Observations and Analysismentioning

confidence: 64%

Section: Introductionmentioning

confidence: 99%

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Propagation of short-period gravity waves at high-latitudes during the MaCWAVE winter campaign

et al. 2006

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“…More often than not, however, the mesospheric signal at 557.7 nm dominates image sets at that wavelength. Yet, due to the ICCD detector in use during this 5-year reporting period, it was challenging to find gravity wave events at their nominal brightness variations, e.g., the typically 1-5% brightness variations recorded at Millstone Hill where we employ a more sensitive bare-CCD detector (Smith et al, 2000). Nevertheless, bright events do occur, as shown in Fig.…”

Section: Airglow Structures Associated With Mesospheric Dynamicsmentioning

confidence: 97%

Imaging science at El Leoncito, Argentina

Martinis¹,

Baumgardner²,

Smith³

et al. 2006

Ann. Geophys.

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Abstract. Thermospheric and mesospheric structures are studied using an all-sky imager located at El Leoncito, Argentina (31.8 • S, 69.3 • W, -18 • mag lat). This site has relatively high geographic latitude for a location under the crest of the equatorial ionization anomaly (EIA), and thus observations can be used to study the intrusion of several equatorial processes into the midlatitude domain. In addition, it has a conjugate point close to the field of view of our companion imager at Arecibo, PR, allowing for the study of interhemispheric effects. Four types of phenomena were studied using 630.0 nm and 777.4 nm observations: (1) highlystructured airglow depletions associated with the RayleighTaylor instability/equatorial spread-F (RTI/ESF) process, (2) brightness waves (BW) associated with the midnight temperature maximum (MTM), (3) strong airglow enhancements associated with the positive phase of ionospheric storms, and (4) simple (non-structured) bands of airglow depletions with characteristics matching a Perkins-like instability. Using 557.7 nm mesospheric observations, a fifth category of study deals with gravity waves probably generated by lower atmospheric disturbances, and mesospheric bores related to strong vertical temperature gradients.While ESF depletions and BW events are detected fairly frequently, the mid-latitude bands are not, and thus their successful imaging at El Leoncito offers the first example of the coupling from mid-latitudes to low-latitudes in the South American longitude sector. Preliminary results on these features are presented in this paper. Taken together, these five types of optical structures offer the opportunity to investigate coupling, both in altitude and latitude, of aeronomic processes at low latitudes in an under-sampled longitude sector in the Southern Hemisphere.

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“…It is used to estimate the horizontal wind U . Figure 8 gives "Blocking diagrams" (e.g., Ryan, 1991;Taylor et al, 1993 wind may not represent the real wind; (2) critical layer filtering may not be a dominant factor determining the wave directions. As the blocking diagram can partly explain the bands anisotropic distributions, the non-uniform distribution of wave sources and wave ducts may also contribute to the anisotropy of the bands propagation directions in different seasons.…”

Section: Anisotropic Propagation Direction Of Bands and Its Possible mentioning

confidence: 99%

Statistical characteristics of gravity wave activities observed by an OH airglow imager at Xinglong, in northern China

Yue

et al. 2011

Ann. Geophys.

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Abstract. An all-sky airglow imager (ASAI) was installed at Xinglong, in northern China (40.2 • N, 117.4 • E) in November 2009 to study the morphology of atmospheric gravity waves (AGWs) in the mesosphere and lower thermosphere (MLT) region. Using one year of OH airglow imager data from December 2009 to November 2010, the characteristics of short-period AGWs are investigated and a yearlong AGW climatology in northern China is first ever reported. AGW occurrence frequency in summer and winter is higher than that in equinoctial months. Observed bands mainly have horizontal wavelengths from 10 to 35 km, observed periods from 4 to 14 min and observed horizontal phase speeds in the range of 30 to 60 m s −1 . Most of the bands propagate in the meridional direction. The propagation directions of the bands show a strong southwestward preference in winter, while almost all bands propagate northeastward in summer. Although the wind filtering in the middle atmosphere may control AGW propagations in the zonal direction, the nonuniform distribution of wave sources in the lower atmosphere may contribute to the anisotropy in the meridional direction in different seasons. Additionally, as an indication of local instability, the characteristics of ripples are also analyzed. It also shows seasonal variations, occurring more often in summer and winter and mainly moving westward in summer and eastward in winter.

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Mesospheric gravity wave imaging at a subauroral site: First results from Millstone Hill

Cited by 55 publications

References 56 publications

Propagation of short-period gravity waves at high-latitudes during the MaCWAVE winter campaign

Propagation of short-period gravity waves at high-latitudes during the MaCWAVE winter campaign

Imaging science at El Leoncito, Argentina

Statistical characteristics of gravity wave activities observed by an OH airglow imager at Xinglong, in northern China

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