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

Gabriel Augusto Giongo,Diego Janches,Wayne Hocking,Igo Paulino,Nelson Jorge Schuch,Gabriela Dornelles Bittencourt,Neusa Maria Paes Leme,José Valentin Bageston,Paulo Prado Batista,David C Fritts,Cristiano Max Wrasse

doi:10.5194/angeo-36-253-2018

Abstract

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, m2, was calculated for each of the four waves. Even though no clearly defined duct (indicated by positive values of m2 sandwiched between layers above and below with m2 < 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. Keywords. Atmospheric composition and structure (airglow and aurora) – meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides)

Highlights

Atmospheric gravity waves have been an expanding research area in the last years due to several effects and contributions of these waves in the atmospheric circulation, structure, and variability (Fritts and Alexander, 2003).In addition to the vertical transport of momentum and energy, the gravity waves are important when they are sub-Published by Copernicus Publications on behalf of the European Geosciences Union.G
We examine the atmospheric conditions of the medium in which these events propagated, using temperature data obtained from the TIMED/SABER instrument and wind data obtained from the meteor radar installed at Ferraz Station
The first event is similar to a peculiar wave event reported by Smith et al (2017) who presented a twin bore event that occurred over Europe in March 2013 and their analysis suggested that these bores were associated with a larger-scale mesospheric disturbance, which was associated with a severe meteorological phenomenon

Summary

Introduction

Atmospheric gravity waves have been an expanding research area in the last years due to several effects and contributions of these waves in the atmospheric circulation, structure, and variability (Fritts and Alexander, 2003).In addition to the vertical transport of momentum and energy, the gravity waves are important when they are sub-G. Atmospheric gravity waves have been an expanding research area in the last years due to several effects and contributions of these waves in the atmospheric circulation, structure, and variability (Fritts and Alexander, 2003). In addition to the vertical transport of momentum and energy, the gravity waves are important when they are sub-. Since the discovery of the wave fronts, commonly called mesospheric bores (Taylor et al, 1995), several reports have been published on both experimental research (Li et al, 2013; Narayanan et al, 2012; Walterscheid et al, 2012; Medeiros et al, 2016) and modeling of the phenomenon (Seyler, 2005; Laughman et al, 2009; Fritts et al, 2013; Snively et al, 2013)

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Discussion

Conclusion