Affiliation:
1. Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy SB RAS
Abstract
The work uses data on the geomagnetic index Dst for the period 1966–2015. Under quiet conditions, the occurrence of seasonal variations of the daily average Dst index depends on geometric factors of the interaction between the solar wind and the magnetosphere; and under disturbed conditions, on the development of a partial ring current in the magnetosphere. At large negative values of the Dst index, there is no seasonal variation in it. The imperfection of the network of Dst stations is assumed to lead to the formation of annual variation in Dst. The formation of a semiannual variation is associated with the movement of the plasma sheet relative to the plane of the geomagnetic equator during the annual rotation of Earth around the Sun. Based on the data on semiannual variations in the number of days n(Dst), the critical daily average value of the geomagnetic index Dst is determined, starting from which we can speak of disturbed days: Dst≤–24 nT.
Publisher
Infra-M Academic Publishing House
Subject
Space and Planetary Science,Atmospheric Science,Geophysics
Reference23 articles.
1. Bartels J. Terrestrial magnetic activity and its relations to solar phenomena. Terrestrial Magnetism and Atmospheric Electricity. 1932, vol. 37, iss. 1, pp. 1–52., Bartels J. Terrestrial magnetic activity and its relations to solar phenomena. Terrestrial Magnetism and Atmospheric Electricity. 1932, vol. 37, iss. 1, pp. 1–52.
2. Chen H.-F. Analysis of the diurnal and semiannual variations of Dst index at different activity levels. J. Geophys. Res. 2004, vol. 109, A03212. DOI: 10.1029/2003JA009981., Chen H.-F. Analysis of the diurnal and semiannual variations of Dst index at different activity levels. J. Geophys. Res. 2004, vol. 109, A03212. DOI: 10.1029/2003JA009981.
3. Cliver E.W., Kamide Y., Ling A.G. Mountains versus valleys: Semiannual variation of geomagnetic activity. J. Geophys. Res. 2000, vol. 105, iss. A2, pp. 2413–2424. DOI: 10.1029/ 1999JA900439., Cliver E.W., Kamide Y., Ling A.G. Mountains versus valleys: Semiannual variation of geomagnetic activity. J. Geophys. Res. 2000, vol. 105, iss. A2, pp. 2413–2424. DOI: 10.1029/ 1999JA900439.
4. Cliver E.W., Kamide Y., Ling A.G., Yokoyama N. Semiannual variation of the geomagnetic Dst index: Evidence for a dominant nonstorm component. J. Geophys. Res. 2001, vol. 106, iss. A10, pp. 21297–21304. DOI: 10.1029/2000JA000358., Cliver E.W., Kamide Y., Ling A.G., Yokoyama N. Semiannual variation of the geomagnetic Dst index: Evidence for a dominant nonstorm component. J. Geophys. Res. 2001, vol. 106, iss. A10, pp. 21297–21304. DOI: 10.1029/2000JA000358.
5. Cortie A.L. Sun-spots and terrestrial magnetic phenomena 1898–1911: The cause of the annual variation of magnetic disturbances. Mon. Not. Roy. Astron. Soc. 1912, vol. 73, pp. 52–60. DOI: 10.1093/mnras/73.1.52., Cortie A.L. Sun-spots and terrestrial magnetic phenomena 1898–1911: The cause of the annual variation of magnetic disturbances. Mon. Not. Roy. Astron. Soc. 1912, vol. 73, pp. 52–60. DOI: 10.1093/mnras/73.1.52.
Cited by
4 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献