In this study, we report the climatology of migrating and non-migrating tides in mesopause winds estimated using multiyear observations from three meteor radars in the southern equatorial region. The results reveal that the climatological patterns of tidal amplitudes by meteor radars is similar to the Climatological Tidal Model of the Thermosphere (CTMT) results and the differences are mainly due to the effect of the stratospheric sudden warming (SSW) event.

Solar atmospheric tides are natural oscillations of 24, 12, 8... hours that contribute to the circulation of the atmosphere from low to high altitudes. The Sun heats the atmosphere periodically because, mainly, water vapor and ozone absorb solar radiation between the ground and 50 km height during the day. Tides propagate upward and they can be observed in, for example, the wind field. This work presents diurnal tides observed by meteor radars which measure wind between 80 and 100 km height.

Global coverage measurements made by satellites have provided observational studies which have shown the presence of four peaks in global longitudinal structures from global local time observations of equatorial ionization anomalies. The structures seen in the ionosphere are related to the diurnal non-migrating wave that comes from the troposphere and can be noticed in periods of low and high solar activity in the low-latitude ionosphere regions, mainly at altitudes from ~ 250 km up to ~ 800 km.

This work presents four events of mesosphere fronts observed on King George Island, Antarctic Peninsula, in the year 2011. The atmospheric background environment was analyzed to investigate the propagation conditions for all cases. To investigate the sources for such cases, satellite images were used. In two cases, we found that strong tropospheric instabilities were potential sources, and in the other two cases, it was not possible to associate them with tropospheric sources.

A comparative study of the quasi-16-day wave in the middle from three Brazilian stations, indicates multiple modes of the concerned wave component. The wave amplitude shows maxima in summer and winter. A potential coupling of the concerned wave with other short period planetary waves is found. The dominant wave components vary from the westward to eastward from the tropical to mid-latitude in the stratosphere. The prevailing westerly wind may favor the wave filtering of westward waves.

This paper reports two consecutive mesospheric bores observed in the airglow emissions (OH and OI5577). Both bores propagated to the east and showed similar spectral characteristics. However, the first one exhibited a dark leading front with several trailing waves behind and progressed into a brighter airglow region. However, the second bore, observed in the OH layer, was comprised of several bright waves propagating into a darker airglow region.

Multi-year observations of gravity wave momentum fluxes have been analyzed at three different sites using meteor radar data. This is a first, as no such experimental results on the latitudinal dependence of these parameters at low latitudes had been derived with ground-based instruments in the MLT region before. Until now similar studies had been carried out with satellites and circulation models. Therefore this thematic can be lead to a valuable scientific contribution.