Estudos de derivas ionosfericas por meio de ionosondas digitais / Ionospheric drift studies by digital ionosondes

AUTOR(ES)
DATA DE PUBLICAÇÃO

1998

RESUMO

The ionospheric plasma drifts over the Brazilian region were studied using data from the digital ionosondes DGS256, at São Luís (MA) (2,3°S; 42°W) and CADI (Canadian Advanced Digital Ionosonde), at Fortaleza (CE) (4°S; 38°W), both instruments located at equatorial region. In order to validate the use of those instruments to measure ionospheric plasma drifts, we made intercomparison of the results of both instruments, and comparison with previous results available in the literature, as well, seeking for one more instrumentation option, and so future ionospheric drift research development over those Brazilian regions. It was observed that ionospheric vertical drift velocity measured by DGS256 did not totally agree with that exhibited by Jicamarca s incoherent scatter radar due to instrumental differences. The drift measured by the radar is the electromagnetic drift while the DGS256 measures the apparent drift. However the pre-reversal enhancement that is a well known characteristic of the vertical drift velocity at equatorial latitudes after sunset, is also observed on DGS256 drifts over São Luís. The zonal drift provided by DGS256 agrees well with that obtained by the Jicamarca s radar. The comparison between DGS256 and CADI vertical drift velocities shows good agreement during some time periods and under certain magnetic activity conditions. The results are discussed in terms of the variability of the low latitude electric fields and the differences between quiet and disturbed conditions.

ASSUNTO(S)

ionossondas digitais sao luis (ma) derivas eletromagneticas plasma ionosferico campo geomagnetico ionosfera campos eletricos geofisica espacial

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