A Decade of Airglow Observation of Mesospheric Fronts over the Brazilian Equatorial Region

Abstract

Mesospheric fronts were observed over São João do Cariri (7.4ºS, 36.5ºW), in the northeast region of Brazil, from September 2011 to June 2021 using an all sky airglow imager. The occurrence of the mesospheric fronts presented a well defined seasonality  with maximum in the Spring period of ten consecutive years. In addition, an anisotropy was observed in the preferential propagation direction, in which most of the front propagated to the northeast. These results suggest that the seasonality and anisotropy can be produced due to either the location of sources or the filtering process associated with the wind system. Other important aspects like the statistics of trailing waves and ripples observed simultaneously were reported as well.