On the Semiannual Variation of Geomagnetic Activity and its Relation to the Solar Corpuscular Radiation

Geomagnetic activity with global influence is an essential object of space weather research and is a significant link in the section of the solar wind-magnetospheric coupling process. Research so far provides strong evidence that geomagnetic activity affects stock investment decisions by influencing human health, mood, and human behaviours. Therefore, this research investigates the empirical association between geomagnetic activity and stock market return. Overall, we find that geomagnetic activity exerts a negative influence on the return of the US stock market. Further, market liquidity effectively magnifies the effect of geomagnetic activity. Inconsistent with previous literature, this effect is not mainly caused by the semiannual variation of geomagnetic activity. Our research contributes to the introduction of geomagnetic indices to financial economics studies on the impact of geomagnetic activity influence on stock market return.

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On the semiannual and annual variations of geomagnetic activity and components

Annales Geophysicae ◽

10.5194/angeo-22-3583-2004 ◽

2004 ◽

Vol 22 (10) ◽

pp. 3583-3588 ◽

Cited By ~ 15

Author(s):

J.-L. Le Mouël ◽

E. Blanter ◽

A. Chulliat ◽

M. Shnirman

Keyword(s):

Time Scales ◽

Geomagnetic Activity ◽

Activity Index ◽

Magnetic Activity ◽

Amplitude Ratios ◽

Time Constants ◽

Annual Variations ◽

Geographical Variability ◽

Semiannual Variation ◽

Magnetic Observatories

Abstract. The semiannual and annual lines in a long series of magnetic observatories daily values, as well as in the aa-activity index series, are investigated. For both periods, amplitudes and phases of the lines corresponding to the different series present grossly common variations on decadal time scales; relative phases and amplitude ratios between the observatories change with the same time constants. The results are briefly discussed with regards to commonly received theories of the semiannual variation of magnetic activity, and some possible mechanisms for the observed geographical variability are suggested.

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Latitudinal effect in semiannual variation of geomagnetic activity

Journal of Geophysical Research Atmospheres ◽

10.1029/2002ja009467 ◽

2003 ◽

Vol 108 (A5) ◽

Cited By ~ 6

Author(s):

W. Lyatsky ◽

A. Tan

Keyword(s):

Geomagnetic Activity ◽

Semiannual Variation ◽

Latitudinal Effect

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<I>a<sub>p</sub></I>-index solar wind driving function and its semiannual variations

Annales Geophysicae ◽

10.5194/angeo-25-1465-2007 ◽

2007 ◽

Vol 25 (7) ◽

pp. 1465-1469 ◽

Cited By ~ 3

Author(s):

A. A. Petrukovich ◽

M. Y. Zakharov

Keyword(s):

Solar Wind ◽

Seasonal Variation ◽

Response Function ◽

Geomagnetic Activity ◽

Linear Term ◽

Response Functions ◽

Driving Function ◽

Semiannual Variation ◽

Wind Input ◽

Ap Index

Abstract. Semiannual variation of geomagnetic activity and ap-index in particular is supposed to consist of heliospheric factor (axial hypothesis and Russell-McPherron effect) and magnetospheric/ionospheric factor (equinoctical hypothesis). In our investigation we express ap-index as a magnetospheric response function to solar wind and IMF input. Seasonal variation in ap-index on average (1963–2003) is ~4 nT and consists of ~2.1–2.3 nT of magnetospheric/ionospheric part, 0.6–1.3 nT of heliospheric part (including 0.2–0.3 nT of R-M effect), 0.1–0.4 nT is due to the non-linear term. 90% confidence range of all estimates is ~0.1–0.25 nT. While autumn/spring magnetospheric response functions are almost identical, there is substantial difference between winter and summer functions. The increase of solar wind input in autumn and spring is also different by a factor of two.

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Origins of the semiannual variation of geomagnetic activity in 1954 and 1996

Annales Geophysicae ◽

10.5194/angeo-22-93-2004 ◽

2004 ◽

Vol 22 (1) ◽

pp. 93-100 ◽

Cited By ~ 18

Author(s):

E. W. Cliver ◽

L. Svalgaard ◽

A. G. Ling

Keyword(s):

Solar Wind ◽

Geomagnetic Activity ◽

Solar Minimum ◽

High Speed ◽

Solar Wind Speed ◽

Coronal Holes ◽

Heliospheric Current Sheet ◽

Solar Cycles ◽

Axial Variation ◽

Semiannual Variation

Abstract. We investigate the cause of the unusually strong semiannual variation of geomagnetic activity observed in the solar minimum years of 1954 and 1996. For 1996 we separate the contributions of the three classical modulation mechanisms (axial, equinoctial, and Russell-McPherron) to the six-month wave in the aam index and find that all three contribute about equally. This is in contrast to the longer run of geomagnetic activity (1868-1998) over which the equinoctial effect accounts for ∼70% of the semiannual variation. For both 1954 and 1996, we show that the Russell-McPherron effect was enhanced by the Rosenberg-Coleman effect (an axial polarity effect) which increased the amount of the negative (toward Sun) [positive (away from Sun)] polarity field observed during the first [second] half of the year; such fields yield a southward component in GSM coordinates. Because this favourable condition occurs only for alternate solar cycles, the marked semiannual variation in 1954 and 1996 is a manifestation of the 22-year cycle of geomagnetic activity. The 11-year evolution of the heliospheric current sheet (HCS) also contributes to the strong six-month wave during these years. At solar minimum, the streamer belt at the base of the HCS is located near the solar equator, permitting easier access to high speed streams from polar coronal holes when the Earth is at its highest heliographic latitudes in March and September. Such an axial variation in solar wind speed was observed for 1996 and is inferred for 1954. Key words. Magnetosphere (solar wind – magnetosphere interactions; storms and substorms)

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