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Quasi‐biennial geomagnetic variation caused by the Sun
Author(s) -
Sugiura Masahisa
Publication year - 1976
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl003i011p00643
Subject(s) - earth's magnetic field , atmospheric sciences , solar wind , sunspot , variation (astronomy) , physics , amplitude , flux (metallurgy) , cosmic ray , geophysics , environmental science , magnetic field , meteorology , climatology , geology , astrophysics , quantum mechanics , materials science , metallurgy
Clear evidence for the existence of a quasi‐biennial geomagnetic variation is shown by an analysis of annual averages of the horizontal (H) component of the geomagnetic field observed at five observatories. The analysis uses a numerical filter, which is equivalent to taking the second order time derivative of the time series. The cause for the variation is external to the earth because its amplitude depends on magnetic activity. The second order time derivative of H is well correlated with the corresponding time derivatives of the relative sunspot number and 10.7 cm solar flux. It is suggested that quasi‐biennial oscillations observed in the geomagnetic field, cosmic rays, stratospheric zonal wind and temperature, total ozone, and other meteorological parameters could be produced by a common cause on the sun.