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Ann. Geophys., 25, 399-406, 2007
www.ann-geophys.net/25/399/2007/
© European Geosciences Union 2007


MLT gravity wave climatology in the South America equatorial region observed by airglow imager

A. F. Medeiros1, H. Takahashi2, R. A. Buriti1, J. Fechine2, C. M. Wrasse2, and D. Gobbi2
1Universidade Federal Campina Grande (UFCG), Av. Aprígio Veloso 882, Bodocongó, Campina Grande, Paraíba, 58.109–170, Brazil
2Instituto Nacional de Pesquisas Espaciais (INPE), Av dos Astronautas 1758, C. Postal: 515 São José dos Campos, São Paulo, 12.201–970, Brazil

Abstract. An all-sky CCD imager for OH, O2 and OI (557.7 nm) airglow emission measurements was operated at São João do Cariri (Cariri), Brazil (7° S, 36° W), from October 2000 to December 2004. A large amount of image data, more than 3000 h of observation and around 1000 wave events, makes it possible to classify the gravity wave characteristics, which are statistically significant. The observed waves show a typically short horizontal wavelength (5–45 km) and a short period (5–35 min), and horizontal phase speeds of 1 to 80 m/s. In most cases band-type waves (horizontal wavelength between 10 and 60 km) showed a clear preference for the horizontal propagation direction from the South American continent to the Atlantic Ocean. Ripples also have similar features but with different anisotropy. In this paper we focus our discussion on the wave characteristics of the bands and ripples and a comparison between them.

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Citation: Medeiros, A. F., Takahashi, H., Buriti, R. A., Fechine, J., Wrasse, C. M., and Gobbi, D.: MLT gravity wave climatology in the South America equatorial region observed by airglow imager, Ann. Geophys., 25, 399-406, 2007.   Bibtex   EndNote   Reference Manager

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