Observação de oscilações de 3-4 dias na mesosfera-ionosfera equatorial.

Abstract

Vertical coupling in the low latitude atmosphere-ionosphere system driven by the 3-4 day wave in the equatorial MLT region was investigated. In this work a 3-4 day wave event during the period from January to December of 2005 identi ed in the neutral winds by radar measurements located at São João do Cariri-PB, Brazil. The 3-4 day variation in the ionospheric electric currents in the E region registered by perturbations in the geomagnetic eld, was detected in the data from 4 magnetometer located in the equatorial region. The results showed that only the oscillations that occurred in the zonal winds in February-March, May-June, August, and October-November, are compatible with the ultra-fast Kelvin wave propagation. The vertical phase structure was descendent, compatible with ascending wave energy, and vertical wavelengths of about 45 km were found for in the rst, second and fourth events, the third event 62 km. The results showed quasi-simultaneous 3-4 day oscillation in the geomagnetic eld and in the MLT winds, in which the of propagation is eastward, it can be interpreted as due to ultra-fast Kelvin wave, except for the third event that showed westward propagation. The parameter that appears to be a a ected is the dynamo electric eld.