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)