@Article{AbduBatMacSobMur:1996:PeChSp,
               author = "Abdu, Mangalathayil Ali and Batista, Inez Staciarini and 
                         Macdougall, J. and Sobral, Jose Humberto Andrade and 
                         Muralikrishna, Polinaya",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Permanent changes in sporadic E layers over Fortaleza, Brazil",
              journal = "Journal of Geophysical Research",
                 year = "1996",
               volume = "101",
               number = "A12",
                pages = "2629--2640",
             keywords = "AERONOMIA.",
             abstract = "We present an evaluation of global-scale equatorial and low 
                         latitude ionospheric disturbances in response to the 
                         weak-to-moderate disturbed conditions that marked the 
                         SUNDL,kL/ATLAS 1 twelvc-day campaign of March 22 to April 2, 1992, 
                         lonosonde data from South American and Indian-Asian longitudes are 
                         analyzed to examine first the climatological (the average) pattern 
                         of the critical F region parameters, (the layer peak density and 
                         height) in comparison with the empirical International Reference 
                         Ionospheric model, and then to characterize the day-to-day 
                         variabilities aiming at identifying potential causal contributions 
                         from either disturbance zonal and meridional winds or 
                         magnetosphcric and disturbance dynamo electric fields. Included in 
                         this analysis are data from South American midlatitude locations 
                         which are used to determine meridional winds using an adaptation 
                         of the servo analysis technique in the Field Line Integrated 
                         Plasma (FLIP) model. We have made an assessment of the causal 
                         mechanism of the day-to-day variabilities as arising from latitude 
                         dependent disturbance meridional winds, and from electric fields 
                         produced by disturbance zonal winds and disturbance dynamo. While 
                         the contribution from disturbance meridional winds decreases from 
                         middle to equatorial latitudes, that of the electric fields 
                         maximizes around the equator. In particular, first-time evidence 
                         based on ionosonde data is provided for a disturbance dynamo 
                         electric field in the equatorial ionosphere. It is found that 
                         there are two time intervals of maximum ionospheric variability 
                         resulting from the weak to moderate magnetospheric disturbance 
                         conditions that prevailed during the campaign: one near the 
                         evcning/postsunset hours and the other in the postmidnight-sunrise 
                         hours over low latitudes. At midlatitudes a broad maximum of the 
                         response occurs from premidnight to morning hours. We provide a 
                         comparison of results for the South American and Indian-Asian 
                         longitudes and a discussion of the competing roles of the 
                         disturbance zonal and meridional winds, and magnetospheric and 
                         disturbance dynamo electric fields as a function of latitude.",
                  doi = "10.1016/S0273-1177(97)00610-8",
                  url = "http://dx.doi.org/10.1016/S0273-1177(97)00610-8",
                 issn = "0148-0227 and 2156-2202",
                label = "8790",
             language = "en",
           targetfile = "abdu_permanent.pdf",
        urlaccessdate = "20 maio 2024"
}