Thermospheric meridional winds inferred from ionospheric soundings / Ventos termosféricos meridionais inferidos por meio de sondagens ionosféricas

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Nighttime thermospheric neutral winds aligned to the magnetic meridian are derived from F-region height variations, over two equatorial stations, Manaus (2.9°S, 60.0°W, dip latitude 6.06°N) and Palmas (10.2°S, 48.2°W, dip latitude 6.2°S) and one low latitude station, São José dos Campos (23.2°S, 45.9°W, dip latitude 18.26°S), in the Brazilian sector. The parameters hpF2 and hF, which were used, were obtained by three time-synchronized digital ionosonde observations. Measurements on some selected magnetically quiet and magnetically disturbed nights, during the period August/September, 2002, are used in the present study. An extension of the servo model is applied in order to infer the magnetic meridional component of the thermospheric neutral winds over the low latitude station. The coefficients of diffusion, recombination and loss rate, required in the servo equations, are calculated using an appropriated atmospheric model. The results obtained are compared with a semi-empirical global horizontal wind model (HWM-93). Some of the results are compared with observational measurements from a low latitude station in the Brazilian sector, obtained using an OI 630 nm Fabry-Perot interferometer. These comparisons are used to check the validity of the method in calculating the velocity and direction of the meridional winds over the equatorial and low-latitude regions. The present study assumes great importance in the understanding of the thermosphere-ionosphere system behavior and response during both geomagnetically quiet and disturbed conditions.

ASSUNTO(S)

sondagem ionosférica ionospheric sounding rádio propagação região f f region ionospheric drift radio propagation deriva ionosférica atmospheric models space geophysics geofÍsica espacial modelos atmosféricos

ACESSO AO ARTIGO

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