Estudo da propagação de ondas de gravidade na ionosfera equatorial, utilizando observações em Manaus (2,9°s, 60°w)

Abstract

This work studies the behavior of gravity waves (GW) in the ionosphere over the city of Manaus (2,9oS, 60oW). For that purpose, ionograms which are specters of frequency in function of the altitude and the secular variation of the height for a set of fixed frequencies (3, 4, 5, 6, 7 8 MHz). The observations were analyzed carried through by a system of called radar ionosonde. This system operates in the radio frequency band between 1and 20 MHz. The studied period comprehends a part of solar cycle 23, that is, since August of 2002 until December of 2006. Additionally, it was also observed that the ionosphere presents strong disturbances during geomagnetically quiet periods. These disturbances are attributed to the propagation of gravity waves which are generated in the lower atmosphere and propagate up to the high atmosphere and ionosphere.