@Article{JesusSaGuFaAbPiLi:2011:FrIoPa,
               author = "Jesus, Rodolfo de and Sahai, Y. and Guarnieri, F. L. and Fagundes, 
                         P. R. and Abreu, Alessandro Jos{\'e} de and Pillat, Valdir Gil 
                         and Lima, W. L. C.",
          affiliation = "Univ Vale Paraiba UNIVAP, IP\&D and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and Univ Vale Paraiba UNIVAP, IP\&D 
                         and Univ Vale Paraiba UNIVAP, IP\&D and Univ Vale Paraiba UNIVAP, 
                         IP\&D and {} and Univ Luterana Brasil ULBRA, Ctr Univ Luterano 
                         Palmas CEULP, Palmas, TO",
                title = "F-region ionospheric parameters observed in the equatorial and low 
                         latitude regions during medium solar activity in the Brazilian 
                         sector and comparison with the IRI-2007 model results",
              journal = "Advances in Space Research",
                 year = "2011",
               volume = "47",
               number = "4",
                pages = "718--728",
                month = "Feb",
             keywords = "Ionosphere, F-region, International Reference Ionosphere-2007.",
             abstract = "The ionospheric sounding observations using the Canadian Advanced 
                         Digital Ionosondes (CADIs) operational at Palmas (PAL; 10.2 
                         degrees S, 48.2 degrees W; dip latitude 6.6 degrees S; a 
                         near-equatorial station), and Sao Jose dos Campos (SJC, 23.2 
                         degrees S, 45.9 degrees W; dip latitude 17.6 degrees S; a 
                         low-latitude station located under the southern crest of the 
                         equatorial ionospheric anomaly), Brazil, are analyzed during the 
                         different seasons viz., winter (June and July 2003), spring 
                         (September and October 2003), summer (December 2003 and January 
                         2004), and fall (March and April 2004). The period used has medium 
                         solar activity (sunspot number between 77.4 and 39.3). The 
                         seasonal mean variations (using only geomagnetically quiet days) 
                         of the ionospheric parameters foF2 (critical frequency of the 
                         F-region), hpF2 (virtual height at 0.834 foF2; considered to be 
                         close to hmF2 (peak height of the F-region)), and h'F (minimum 
                         virtual height of the F-region) are calculated and compared 
                         between PAL and SJC. The prominent differences between PAL and SJC 
                         are as follows: h'F variations show strong post-sunset enhancement 
                         at PAL during the seasons of spring, summer, and fall; hpF2 
                         variations show pre-sunrise uplifting of the F-layer at both 
                         stations during all the seasons and the hpF2 values during the 
                         daytime are lower at SJC compared with PAL during all the seasons; 
                         the foF2 variations show mid-day bite-out at PAL during all the 
                         seasons and SJC shows strong equatorial ionospheric anomaly during 
                         summer and fall seasons. Also, the seasonal variations of the 
                         ionospheric parameters foF2 and hpF2 (with +/- 1 standard 
                         deviation) observed at PAL and SJC are compared with the IRI-2007 
                         model results of foF2 and hmF2. In addition, variations of the 
                         foF2 and hpF2 observed at SJC are compared with the IRI-2001 model 
                         results of foF2 and hmF2. It should be pointed out that the 
                         ionospheric parameter hpF2 is much easier to obtain using computer 
                         program developed at UNIVAP compared with hmF2 (using POLAN 
                         program). During the daytime due to underlying ionization hpF2 
                         estimated is higher (approximately 50 km) than the true peak 
                         height hmF2. During the nighttime hpF2 is fairly close to hmF2. 
                         The comparison between the foF2 variations observed at PAL and SJC 
                         with the IRI-2007 model results shows a fairly good agreement 
                         during all the seasons. However, the comparison between the hpF2 
                         variations observed at PAL and SJC with the hmF2 variations with 
                         the IRI-2007 model results shows: (1) a fairly good agreement 
                         during the nighttime in all the seasons; (2) the model results do 
                         not show the pre-sunrise uplifting of the F-layer at PAL and SJC 
                         in any season; (3) the model results do not show the post-sunset 
                         uplifting of the F-layer at PAL; (4) considering that, in general, 
                         hpF2 is higher than hmF2 during the daytime by about 50 km, the 
                         model results are in good agreement at PAL and SJC during all the 
                         seasons except summer at SJC, when large discrepancies in the 
                         observed hpF2 and modeled hmF2 are observed. Also, it has been 
                         observed that, in general, hmF2 values for SJC calculated using 
                         IRI-2001 are higher than IRI-2007 during the daytime in winter, 
                         summer, and fall. However, hmF2 values for SJC calculated using 
                         IRI-2001, are lower than IRI-2007 during the nighttime in spring. 
                         (C) 2010 COSPAR. Published by Elsevier Ltd. All rights reserved.",
                  doi = "10.1016/j.asr.2010.10.020",
                  url = "http://dx.doi.org/10.1016/j.asr.2010.10.020",
                 issn = "0273-1177",
                label = "lattes: 1106857072073407 6 JesusSaGuFaAbPiLi:2011:FrIoPa",
             language = "en",
           targetfile = "Jesus-AdvSpaceRes-v-47-n4-p718-28science[2].pdf",
        urlaccessdate = "15 jun. 2024"
}