In this paper we present trends and variations of in the geomagnetic activity as signatures of space weather and climate during the last 166 years. The data used are global and local magnetic activity index series. The global indices are daily aa-numbers for 1868–2010, and the local ones are derived from Helsinki (1844–1897) and Sodankylä (1914–2010) magnetic observatory recordings.
Geomagnetic and solar activity was in deep minimum in early decades of the twentieth century when the global activity was on average about half of that during the last two sunspot cycles in 1986–2009 (23 and 24). However, the prolonged duration of the sunspot cycle 23 (1996–2008) and the slow progress of the solar activity during the present cycle 24, indicate that the Sun will be in less active state during the coming decade. The average magnetic activity in 2008–2009 was lowest for about 100 years.
Solar Wind Solar Activity Solar Cycle Interplanetary Magnetic Field Sunspot Number
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
This is a preview of subscription content, log in to check access.
Bartels J (1934) Twenty-seven day recurrences in terrestrial-magnetic and solar activity, 1923–33. J Geophys Res 39:201–202CrossRefGoogle Scholar
Chapman S, Bartels J (1940) Geomagnetism, Vol. I & II. Oxford Clarendon Press, OxfordGoogle Scholar
Clua De Gonzales A, Gonzales G, Dutra SL (1993) Periodic variation in the geomagnetic activity: a study based on the Ap index. J Geophys Res 98:9215–9231CrossRefGoogle Scholar
Delouis H, Mayaud PN (1975) Spectral analysis of the geomagnetic activity index aa over a 103-year interval. J Geophys Res 80:4681–4688CrossRefGoogle Scholar
Fraser-Smith AC (1972) Spectrum of the geomagnetic activity index Ap. J Geophys Res 77:4209–4220CrossRefGoogle Scholar
Kane RP (1997) Quasi-biennial and quasi-triennial oscillations in geomagnetic activity indices. Ann Geophys 15:1581–1594CrossRefGoogle Scholar
Kane RP (2010) Size of the coming solar cycle 24 based on Ohl’s precursor method. Ann Geophys 28:1463–1466CrossRefGoogle Scholar
Lockwood M (2010) Solar change and climate: an update in the light of the current exceptional solar minimum. Proc R Soc A 466:303–329CrossRefGoogle Scholar
Menvielle M, Berthelier A (1991) The K-derived planetary indices: description and availability. Rev Geophys 29:413–432CrossRefGoogle Scholar
Mursula K, Zieger B, Vilppola JH (2003) Mid-term quasi-periodicities in geomagnetic activity during the last 15 solar cycles: connections to solar dynamo strength. Sol Phys 212:201–217CrossRefGoogle Scholar
Nevanlinna H (2004a) Historical space climate data from Finland: compilation and analysis. Sol Phys 224:395–405CrossRefGoogle Scholar
Nevanlinna H (2004b) Results of the Helsinki magnetic observatory 1844–1912. Ann Geophys 22:1691–1704CrossRefGoogle Scholar
Nevanlinna H, Häkkinen L (2010) Results of Russian geomagnetic observatories in the 19th century: magnetic activity 1841–1862. Ann Geophys 28:917–926CrossRefGoogle Scholar
Nevanlinna H, Kataja E (1993) An extension of the geomagnetic activity series aa for two solar cycles (1844–1868). Geophys Res Lett 20:2703–2706CrossRefGoogle Scholar
Richardson JD, Paularena KI, Belcher JW, Lazarus AJ (1994) Solar wind oscillations with a 1.3 year period. Geophys Res Lett 21:1559–1962CrossRefGoogle Scholar
Russell CT, McPherron RL (1973) Semi-annual variation of geomagnetic activity. J Geophys Res 78:92–108CrossRefGoogle Scholar
Silverman SM, Shapiro R (1983) Power spectral analysis of auroral occurrence frequency. J Geophys Res 88:6310–6316CrossRefGoogle Scholar
Sucksdorff E (1942) Die erdmagnetische Aktivität in Sodankylä in den Jahren 1914–1934. Sanan Valta, KuopioGoogle Scholar
Svalgaard L, Cliver EW (2007) Interhourly variability index of geomagnetic activity and its use in deriving the long-term variation of solar wind speed. J Geophys Res 112:A10111–A10143CrossRefGoogle Scholar
Usoskin IG (2008) A history of solar activity over Millennia. Living Rev Solar Phys 5:1–88CrossRefGoogle Scholar