@Article{NordemannTriv:1992:ExFiPe,
               author = "Nordemann, Daniel Jean Roger and Trivedi, Nalin Babulal",
                title = "Sunspot number time series: exponential fitting and 
                         periodicities",
              journal = "Solar Physics",
                 year = "1992",
               volume = "142",
               number = "2",
                pages = "411--414",
             keywords = "GEOFISICA ESPACIAL.",
             abstract = "In a previous communication, the annual mean sunspot number time 
                         series for the period 1700-1990 A.D. was studied through fitting 
                         with exponential functions of the form N=No.exp(kt) for each 
                         phase. In this letter every solar cycle is reduced to five 
                         characteristic parameters: exponents K and observed durations for 
                         the rising and declining phases and values of the maximum. The 
                         periodicities between 50 and 200 yr for these five parameters are 
                         analyzed and compared between themselves, showing similar patterns 
                         (dominating periodicities at about 59 and 86 yr) and differences 
                         such as different periods for the exponent of the rising (83.5 yr) 
                         and declining (105 yr) phase and for the observed maximum (99 
                         yr).",
                 issn = "0038-0938 and 1573-093X",
                label = "7233",
           targetfile = "1992_nordemann.pdf",
        urlaccessdate = "10 maio 2024"
}