@Article{Kane:2005:IoFoAn,
               author = "Kane, Rajaram Purushotam",
                title = "Ionospheric foF2 anomalies during some intense geomagnetic 
                         storms",
              journal = "Annales Geophysicae",
                 year = "2005",
               volume = "23",
               number = "7",
                pages = "2487 - 2499",
             abstract = "The global evolutions of foF2 anomalies were examined for three 
                         very intense geomagnetic storms, namely the Halloween events of 
                         October-November 2003 (Event X, 29-30 October 2003, Dst-401 nT; 
                         Event Y, 20-21 November 2003, Dst-472 nT), and the largest Dst 
                         storm (Event Z, 13-14 March 1989, Dst-589 nT). For Event X, 
                         troughs (negative storms) were clearly seen for high northern and 
                         southern latitudes. For northern midlatitudes as well as for low 
                         latitudes, there were very strong positive effects on 29 October 
                         2003, followed by negative effects the next day. For Event Y, 
                         there were no troughs in NH high latitudes for morning and evening 
                         hours but there were troughs for night. For midlatitudes and low 
                         latitudes, some longitudes showed strong negative effects in the 
                         early morning as expected, but some longitudes showed strong 
                         positive effects at noon and in the evening hours. Thus, there 
                         were many deviations from the model patterns. The deviations were 
                         erratic, indicating considerable local effects superposed on 
                         general patterns. A disconcerting feature was the presence of 
                         strong positive effects during the 24 h before the storm 
                         commencement. Such a feature appears only in the 24 h before the 
                         geomagnetic storm commencement but not earlier. If genuine, these 
                         could imply a prediction potential with a 24-h antecedence. For 
                         Event Z (13-14 March 1989, equinox), all stations (all latitudes 
                         and longitudes) showed a very strong {"}negative storm{"} in the 
                         main phase, and no positive storms anywhere.",
                 issn = "0992-7689",
             language = "en",
           targetfile = "angeo-23-2487-2005.pdf",
        urlaccessdate = "13 maio 2024"
}