Variations in solar and geomagnetic activity with periods near to 1.3 year

0330243 - GFÚ 2010 RIV PL eng J - Journal Article
Střeštík, Jaroslav
Variations in solar and geomagnetic activity with periods near to 1.3 year.
Central European Journal of Geosciences. Roč. 1, č. 2 (2009), s. 152-156. ISSN 2081-9900. E-ISSN 1896-1517
R&D Projects: GA AV ČR(CZ) IAA300120608
Institutional research plan: CEZ:AV0Z30120515
Keywords : transyear variation * geomagnetic activity * solar activity * wavelet analysis
Subject RIV: DE - Earth Magnetism, Geodesy, Geography

It is known that solar wind velocity fluctuates regularly with a period of about 1.3 years. This periodicity (and other signals with periods near to 1.1 and 0.9 years) has also been observed in biological data. The variation is a temporary feature, mostly being observed in the early 1990s. Here, the occurrence of these periodic signals in solar and geomagnetic activity between 1932 and 2005 has been investigated. The signal with 1.3 year period is present in geomagnetic activity only in a short interval after 1990 and to a lesser extent around 1942. At other times the signal is very weak or not present at all. Other periods are much lower amplitude and appear only sporadically throughout the time investigated.
Permanent Link: http://hdl.handle.net/11104/0176074