author = "Hajra, Rakjumar and Chakraborty, Shyamal Kumar and Tsurutani, 
                         Bruce T. and DasGupta, Ashish and Echer, Ezequiel and Brum, 
                         Christiano G. M. and Gonzalez Alarcon, Walter Dem{\'e}trio and 
                         Sobral, Jos{\'e} Humberto Andrade",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Raja Peary 
                         Mohan College} and {Jet Propulsion Laboratory} and {University of 
                         Calcutta} and {Instituto Nacional de Pesquisas Espaciais (INPE)} 
                         and {Arecibo Observatory/SRI International} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)}",
                title = "An empirical model of ionospheric total electron content (TEC) 
                         near the crest of the equatorial ionization anomaly (EIA)",
              journal = "Journal of Space Weather and Space Climate",
                 year = "2016",
               volume = "6",
                pages = "A29",
                month = "July",
             keywords = "Ionosphere (equatorial), Solar activity, Solar cycle, Total 
                         electron content, Forecasting.",
             abstract = "We present a geomagnetic quiet time (Dst > -50 nT) empirical model 
                         of ionospheric total electron content (TEC) for the northern 
                         equatorial ionization anomaly (EIA) crest over Calcutta, India. 
                         The model is based on the 1980-1990 TEC measurements from the 
                         geostationary Engineering Test Satellite-2 (ETS-2) at the 
                         Haringhata (University of Calcutta, India: 22.58 degrees N, 88.38 
                         degrees E geographic; 12.09 degrees N, 160.46 degrees E 
                         geomagnetic) ionospheric field station using the technique of 
                         Faraday rotation of plane polarized VHF (136.11 MHz) signals. The 
                         ground station is situated virtually underneath the northern EIA 
                         crest. The monthly mean TEC increases linearly with F-10.7 solar 
                         ionizing flux, with a significantly high correlation coefficient 
                         (r - 0.89-0.99) between the two. For the same solar flux level, 
                         the TEC values are found to be significantly different between the 
                         descending and ascending phases of the solar cycle. This 
                         ionospheric hysteresis effect depends on the local time as well as 
                         on the solar flux level. On an annual scale, TEC exhibits 
                         semiannual variations with maximum TEC values occurring during the 
                         two equinoxes and minimum at summer solstice. The semiannual 
                         variation is strongest during local noon with a summer-to-equinox 
                         variability of similar to 50-100 TEC units. The diurnal pattern of 
                         TEC is characterized by a pre-sunrise (0400-0500 LT) minimum and 
                         near-noon (1300-1400 LT) maximum. Equatorial electrodynamics is 
                         dominated by the equatorial electrojet which in turn controls the 
                         daytime TEC variation and its maximum. We combine these long-term 
                         analyses to develop an empirical model of monthly mean TEC. The 
                         model is validated using both ETS-2 measurements and recent GNSS 
                         measurements. It is found that the present model efficiently 
                         estimates the TEC values within a 1-sigma range from the observed 
                         mean values.",
                  doi = "10.1051/swsc/2016023",
                  url = "http://dx.doi.org/10.1051/swsc/2016023",
                 issn = "2115-7251",
             language = "en",
           targetfile = "hajra_an empirical.pdf",
        urlaccessdate = "30 nov. 2020"