Equatorial E region electric fields at the dip equator: 1. Variabilities in eastern Brazil and Peru

Made available in DSpace on 2019-09-12T16:53:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2016Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)National Space Science Center (NSSC), Chinese Academy of Sciences (CAS)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Cornell University [NSF AGS-1433968]The equatorial electrojet (EEJ) is an intense eastward ionospheric electric current centered at about 105 km of altitude along the dip equator, set up by the global neutral wind dynamo that generates the eastward zonal (Ey) and the daytime vertical (Ez) electric fields. The temporal variation of the EEJ is believed to be well understood. However, the longitudinal variability of the Ey and Ez between 100 and 110 km is still quite scarce. Due to their importance overall phenomenology of the equatorial ionosphere, we investigate the variabilities of the Ey and Ez inferred from measurements of the Doppler frequency of Type II echoes provided by coherent backscatter radars installed in locations close to the magnetic equator in the eastern Brazil (2.33 degrees S,44.20 degrees W) and Peru (11.95 degrees S, 76.87 degrees W). This study is based on long-term (609 days for both systems) radar soundings collected from 2001 to 2010. The variabilities of the electric fields are studied in terms of the position of the soundings with respect to the dip equator and the magnetic declination angle. Among the results, Ey and Ez show longitudinal dependence, being higher in Peru than east Brazil. Under quiet geomagnetic activity, the mean diurnal variations of Ey ranged from 0.21 to 0.35 mV/m between 8 and 18 h (LT) in Brazil and from 0.23 mV/m to 0.45 mV/m in Peru, while the mean diurnal variations of the Ez ranges from 7.09 to 8.80 mV/m in Brazil and from 9.00 to 11.18 mV/m in Peru.[Moro, J.; Schuch, N. J.] Southern Reg Space Res Ctr CRS INPE, Santa Maria, RS, Brazil[Denardini, C. M.; Resende, L. C. A.; Chen, S. S.] Natl Inst Space Res INPE, Sao Jose Dos Campos, Brazil[Chen, S. S.] Universidade de Taubaté (Unitau), Dept Elect Eng