Observation of mesospheric gravity waves at Comandante Ferraz Antarctica Station (62° S)

Bageston, José Valentin; Wrasse, C. M.; Gobbi, D.; Takahashi, H.; Souza, Primavera Botelho de

doi:10.5194/angeo-27-2593-2009

Cited by 31 publications

(44 citation statements)

References 18 publications

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“…In our observations at Ferraz Station during 2007, more than 230 gravity wave events were observed (Bageston et al, 2009). The report of only two wave front events (wall event reported by Bageston et al (2011) and the present study), among a large number of gravity wave events, confirms the low occurrence rate of bores at high southern latitudes compared to lower latitudes (Fechine et al, , 2009).…”

Section: Introductionsupporting

confidence: 61%

“…An exposure time of 20 s was used for each image, yielding a sampling interval of ∼38 s since the imager does not have a filter wheel. The original images (1024 × 1024 pixels) were not binned, but cropped to 512 × 512 pixels due to limitations of the optical system (Bageston et al, 2009, which produces a useful image inside of 312 × 312 pixels on the CCD. The quality of the airglow data and its usage were limited by weather conditions to clear sky and new moon periods.…”

Section: Airglow Measurementsmentioning

confidence: 99%

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Observation of a mesospheric front in a thermal-doppler duct over King George Island, Antarctica

et al. 2011

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Abstract.A mesospheric front was observed with an allsky airglow imager on the night of 9-10 July 2007 at Ferraz Station (62 • S, 58 • W), located on King George island on the Antarctic Peninsula. The observed wave propagated from southwest to northeast with a well defined wave front and a series of crests behind the main front. The wave parameters were obtained via a 2-D Fourier transform of the imager data providing a horizontal wavelength of 33 km, an observed period of 6 min, and a horizontal phase speed of 92 m s −1 . Simultaneous mesospheric winds were measured with a medium frequency (MF) radar at Rothera Station (68 • S, 68 • W) and temperature profiles were obtained from the SABER instrument on the TIMED satellite. These wind and temperature profiles were used to estimate the propagation environment of the wave event. A wavelet technique was applied to the wind in the plane of wave propagation at the OH emission height spanning three days centered on the front event to define the dominant periodicities. Results revealed a dominance of near-inertial periods, and semi-diurnal and terdiurnal tides suggesting that the ducting structure enabling mesospheric front propagation occurred on large spatial scales. The observed tidal motions were used to reconstruct the winds employing a least-squares method, which were then compared to the observed ducting environment. Results suggest an important contribution of largescale winds to the ducting structure, but with buoyancy frequency variations in the vertical also expected to be important. These results allow us to conclude that the wave front event was supported by a duct including contributions from both winds and temperature.Correspondence to:

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Section: Introductionsupporting

confidence: 61%

Section: Airglow Measurementsmentioning

confidence: 99%

Observation of a mesospheric front in a thermal-doppler duct over King George Island, Antarctica

et al. 2011

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“…Bageston et al (2009) in their observations at Ferraz Station, during 2007, observed more than 230 gravity wave events, but only two clear cases of mesospheric fronts were reported. The first one was a mesospheric wall (Bageston et al, 2011a) and the second one was a mesospheric bore (Bageston et al, 2011b).…”

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confidence: 95%

Mesospheric front observations by the OH airglow imager carried out at Ferraz Station on King George Island, Antarctic Peninsula, in 2011

et al. 2018

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Abstract. The main goals of this work are to characterize and investigate the potential wave sources of four mesospheric fronts identified in the hydroxyl near-infrared (OH-NIR) airglow images, obtained with an all-sky airglow imager installed at Comandante Ferraz Antarctic Station (EACF, as per its Portuguese acronym) located on King George Island in the Antarctic Peninsula. We identified and analyzed four mesospheric fronts in 2011 over King George Island. In addition, we investigate the atmospheric background environment between 80 and 100 km altitude and discuss the ducts and propagation conditions for these waves. For that, we used wind data obtained from a meteor radar operated at EACF and temperature data obtained from the TIMED/SABER satellite. The vertical wavenumber squared, m 2 , was calculated for each of the four waves. Even though no clearly defined duct (indicated by positive values of m 2 sandwiched between layers above and below with m 2 < 0) was found in any of the events, favorable propagation conditions for horizontal propagation of the fronts were found in three cases. In the fourth case, the wave front did not find any duct support and it appeared to dissipate near the zenith, transferring energy and momentum to the medium and, consequently, accelerating the wind in the wave propagation direction (near to south) above the OH peak (88-92 km). The likely wave sources for these four cases were investigated by using meteorological satellite images and in two cases we could find that strong instabilities were potential sources, i.e., a cyclonic activity and a large convective cloud cell. In the other two cases it was not possible to associate troposphere sources as potential candidates for the generation of such wave fronts observed in the mesosphere and secondary wave sources were attributed to these cases.

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“…Studies employing individual lidar or airglow instruments cannot quantify GW characteristics as fully as combinations of instruments that define horizontal and vertical GW structures and their environments together. Such studies have nevertheless contributed to our initial understanding of GW scales, periods, phase speeds, likely sources, and propagation directions [e.g., Taylor and Hapgood, 1988;Taylor et al, 1993Taylor et al, , 1995aTaylor et al, , 1997Collins et al, 1996;Nakamura et al, 1999;Hu et al, 2002;Bageston et al, 2009;Yue et al, 2009].…”

Section: Introductionmentioning

confidence: 99%

Investigation of a mesospheric gravity wave ducting event using coordinated sodium lidar and Mesospheric Temperature Mapper measurements at ALOMAR, Norway (69°N)

et al. 2014

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New measurements at the ALOMAR observatory in northern Norway (69°N, 16°E) using the Weber sodium lidar and the Advanced Mesospheric Temperature Mapper (AMTM) allow for a comprehensive investigation of a gravity wave (GW) event on 22 and 23 January 2012 and the complex and varying propagation environment in which the GW was observed. These observational techniques provide insight into the altitude ranges over which a GW may be evanescent or propagating and enable a clear distinction in specific cases. Weber sodium lidar measurements provide estimates of background temperature, wind, and stability profiles at altitudes from~78 to 105 km. Detailed AMTM temperature maps of GWs in the OH emission layer together with lidar measurements quantify estimates of the observed and intrinsic GW parameters centered near 87 km. Lidar measurements of sodium densities also allow more precise identification of GW phase structures extending over a broad altitude range. We find for this particular event that the extent of evanescent regions versus regions allowing GW propagation can vary largely over a period of hours and significantly change the range of altitudes over which a GW can propagate.

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Observation of mesospheric gravity waves at Comandante Ferraz Antarctica Station (62° S)

Cited by 31 publications

References 18 publications

Observation of a mesospheric front in a thermal-doppler duct over King George Island, Antarctica

Observation of a mesospheric front in a thermal-doppler duct over King George Island, Antarctica

Mesospheric front observations by the OH airglow imager carried out at Ferraz Station on King George Island, Antarctic Peninsula, in 2011

Investigation of a mesospheric gravity wave ducting event using coordinated sodium lidar and Mesospheric Temperature Mapper measurements at ALOMAR, Norway (69°N)

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