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An extension of the geomagnetic activity index series aa for two solar cycles (1844–1868)
This paper deals with an extension of Mayaud's aa-index series (from 1868 to the present) for two solar cycles 1844–1868. The magnetic data sources are hourly declination readings at the HelsinkiExpand
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Analysis of the seasonal pattern in suicide.
BACKGROUND Suicide has been attributed to social and psychological factors but also to geophysical effects. Of the latter, changes in solar radiation and geomagnetic activities may contribute to theExpand
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Results of the Helsinki magnetic observatory 1844-1912
Abstract. The geomagnetic field declination (D) and horizontal component (H) were observed visually at the Helsinki magnetic observatory between 1844–1912. About 2.0 million single observations ofExpand
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The magnetic bode fallacy
The magnetic moments and angular momenta of Solar System bodies are compared to evaluate the statistical reality of the relation that has come to be called the “magnetic Bode law.” Runcorn hasExpand
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Effects of induced currents on Dst and on magnetic variations at midlatitude stations
[1] Magnetic variations observed at Earth's surface are primarily caused by magnetospheric and ionospheric currents and secondarily affected by currents induced within Earth. For studies of spaceExpand
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Time derivative of the horizontal geomagnetic field as an activity indicator
Abstract. Geomagnetically induced currents (GICs) in technological conductor systems are a manifestation of the ground effects of space weather. Large GICs are always associated with large values ofExpand
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A study on the great geomagnetic storm of 1859: Comparisons with other storms in the 19th century
Abstract Magnetic data (hourly observations) from the Helsinki magnetic observatory were applied to the reconstruction of the extreme geomagnetic Storm on August 28–September 3, 1859. The stormExpand
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On geomagnetic variations during the August–September storms of 1859
Abstract Hourly magnetic readings of H and D from six geomagnetic observatories in Finland and Russia were utilized for analysis of the time behavior of the extreme space weather event ofExpand
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Reconstruction of geomagnetic activity and near-Earth interplanetary conditions over the past 167 yr – Part 4: Near-Earth solar wind speed, IMF, and open solar flux
Abstract. In the concluding paper of this tetralogy, we here use the different geomagnetic activity indices to reconstruct the near-Earth interplanetary magnetic field (IMF) and solar wind flowExpand
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Tests of Sunspot Number Sequences: 2. Using Geomagnetic and Auroral Data
We compare four sunspot-number data sequences against geomagnetic and terrestrial auroral observations. The comparisons are made for the original Solar Influences Data Center (SIDC) composite ofExpand
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