@InProceedings{DenardiniAbduSobrWras:2006:SeStEr,
               author = "Denardini, Clezio Marcos and Abdu, Mangalathayil Ali and Sobral, 
                         Jos{\'e} Humberto Andrade and Wrasse, Cristiano Max",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)}",
                title = "Seasonal study of E-region electric fields at the Brazilian dip 
                         equator estimated from 50 MHz radar observations",
            booktitle = "Abstracts...",
                 year = "2006",
         organization = "Committe on Space Research, 36. (COSPAR).",
             abstract = "Electric fields have been estimate at E region heights based on 
                         coherent backscatter echoes from the equatorial electrojet 
                         obtained with the RESCO radar in 2002. The technique of estimating 
                         electric fields used by [Balsley, 1969] based in determining 
                         Doppler velocity from radar echoes type 2 at low elevation angles 
                         was adapted for use at the 50 MHz radar installed at S{\~a}o 
                         Lu{\'{\i}}s (2.3 S, 44.2 W, dip: -0.5), Brazil. RESCO radar uses 
                         a 7 degree beam width at an elevation angle of 60 degree for 
                         equatorial electrojet sounding. This relatively narrow beam allows 
                         us to deduce the altitude of the scatter directly from the range. 
                         Therefore, we measure the drift profile of the electrojet, which 
                         is used as basis for zonal electric fields estimates. Curve 
                         fitting techniques was used to estimate type 2 Doppler shifts from 
                         echoes power spectra. This method was chosen due to the presence 
                         of the superimposed type 1 Doppler shift around local midday. A 
                         magnetic field aligned integrated conductivity model was used to 
                         calculate Pedersen and Hall conductivities at E region heights 
                         [Denardini, 2005]. Electron density used in this conductivity 
                         model is based in the IRI model corrected by electron densities 
                         obtained from digisonde measured of the daytime equatorial E-layer 
                         (foE) over three locations that constituted a conjugated points 
                         station pair: Campo Grande in south (20.45 S, 54.65 W, dip: -22.5) 
                         and Boa Vista in north (2.8 N, 60.66 W, dip: 22.5), and an 
                         equatorial station, Cachimbo (9.47 S, 54.83 W, dip: -3.9). Our 
                         results are presented and discussed in terms of the South 
                         hemisphere seasons and are comparable to previous ones obtained 
                         for different longitudinal sector, such as by [Reddy et al., 
                         1987], who have used the same approach for estimating electric 
                         field despite the different method for estimating the Doppler 
                         velocities from the radar echoes.",
  conference-location = "Beijing, China",
      conference-year = "2006-07-16",
             language = "en",
           targetfile = "denardini_seasonal.pdf",
        urlaccessdate = "04 maio 2024"
}