Estudo do vento na região da mesosfera e baixa termosfera utilizando medidas de instrumentos de solo e a bordo de satélite.

Abstract

The study of the equatorial region of the mesosphere and lower thermosphere - MLT, between 80 and 110 km altitude, allows us to understand the dynamics of the atmosphere. This work studies the MLT region using wind data obtained by a meteoric radar installed in São João do Cariri (7.4°S; 36.5°W) and by the TIMED Doppler Interferometer - TIDI instrument which is on board of the Satellite - Thermosphere – Ionosphere – Mesosphere Energy and Dynamics - TIMED. In this study, data from the period between January 2005 and December 2006 were used. With the development of the work, it was possible to analyze the behavior of average winds, zonal and meridional components, and evaluate two different techniques of the instruments used. The average meridional winds of São João do Cariri - PB presented characteristics with winds initially to the south between March and the end of September, changing the wind direction to the north from the beginning of October to mid-March. The average zonal winds of São do Cariri – PB headed east until the beginning of January 2005. In general, the zonal winds are basically westward, except at the solstices, and values decrease with altitude. An important characteristic is that, in general, the mean zonal winds present more intense values than the mean meridional winds in the upper mesosphere region, with an annual cycle that describes a poleward flow from summer to winter. The mean meridional winds obtained from the TIDI instrument were calculated using all days within the months as a function of altitude. The presence of diurnal oscillation is clear, propagating with the decrease in altitude in most months. During some months, mainly in autumn and winter, semidiurnal oscillations appear dominant at high levels. The mean zonal winds have smaller amplitudes than the meridional ones. Likewise, the diurnal oscillation is stronger during the summer, while semi-diurnal oscillations appear sporadically at some altitudes. The zonal component, during almost all months, the amplitudes of the zonal winds are greater than those of the meteor radar. Diurnal structures are dominant, but shorter period structures appear practically throughout the year. From the wind recovered by these two techniques, the results showed good agreement.