@Article{AbduBaReMaKhSo:2012:EqRaSp,
               author = "Abdu, Mangalathayil Ali and Batista, I. S. and Reinisch, B. W. and 
                         MacDougall, J. W. and Kherani, E. A. and Sobral, J. H. A.",
          affiliation = "{} and {} and {} and {} and {} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)}",
                title = "Equatorial range spread F echoes from coherent backscatter, and 
                         irregularity growth processes, from conjugate point digital 
                         ionograms",
              journal = "Radio Science",
                 year = "2012",
               volume = "47",
               number = "6",
                month = "Dec.",
             keywords = "digisonde ionogram, ESF strength, coherent backscattering, 
                         conjugate point observation, equatorial spread F, north-south 
                         asymmetry.",
             abstract = "Radio wave returns from spread F plasma structures as received by 
                         ionosondes can originate from total/specular reflection, partial 
                         reflection or coherent backscattering. The dominant mechanism to 
                         account for the spread F traces in equatorial ionograms is still 
                         an open question. Depending upon the precise mechanism, ionosondes 
                         are sensitive to irregularity scale sizes of tens of meters to 
                         several tens/hundreds of kilometers. In this paper we analyze 
                         signatures of range spreading F layer traces in Digisonde 
                         ionograms, taken at Fortaleza (3.9°S, 38.45°W, dip: \−9°) 
                         and Sao Luis (2.33 S, 44.2W, dip angle: \−0.5°), and at a 
                         dip equatorial site Cachimbo (9.5°S, 54.8°W, dip: \−4.2°) 
                         and at its two conjugate sites Bova Vista (02.8°N, 60.7°W, dip: 
                         22.0°) and Campo Grande (20.5 S, 54.7 W, dip \−22.3°) in 
                         Brazil, to determine the dominant process/mechanism of echo 
                         returns from the irregularity structures. A significant component 
                         of the ESF trace structures is found to be consistent with the 
                         echoes originating from coherent backscattering at field line 
                         perpendicular directions. The degree of range spreading of the 
                         echoes is found to increase linearly with the top frequency of the 
                         echo trace, which is shown to be a more precise indicator of the 
                         irregularity strength. Further, the irregularity strength exhibits 
                         a significant increase from the equator toward the EIA crests, as 
                         well as a strong asymmetry between the conjugate sites.",
                  doi = "10.1029/2012RS005002",
                  url = "http://dx.doi.org/10.1029/2012RS005002",
                 issn = "0048-6604",
        urlaccessdate = "07 maio 2024"
}