Results 141 to 150 of about 452 (183)

Geomagnetic Secular Variation

1989
The spatial and temporal variation of the geomagnetic field component annual means has been analyzed. The data used in this study consist of the annual means of the vector magnetic field components measured at nearly one hundred magnetic observatories widely distributed about the Earth.
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Geomagnetic secular variations and surveys

Proceedings of the Physical Society, 1946
The secular variations of the Earth's field call for frequent determinations of the geomagnetic elements at many selected stations on land and at sea. So far, general world magnetic surveys have of necessity been restricted to the surface of the Earth.
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Geomagnetic secular variation in the Indian Ocean

Earth and Planetary Science Letters, 2003
Abstract Annual repeat stations in Australia and in South Africa show that secular variation may change rapidly and over short geographical distances in the Indian Ocean area. Satellite models show large secular variations in the center of the Indian Ocean where there are few island geomagnetic observatories.
J.R. Heirtzler, K. Nazarova
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Geomagnetic secular variation Model E

Journal of Geophysical Research, 1974
We propose a new geomagnetic secular variation model (model E) in which the correlation coefficient between the main dipole and the nondipole components can lie between 0 and +1. This model then describes the total secular variation as a region bounded by lower and upper limits that can be reduced to a single curve only when more adequate data become ...
Czang-Go Baag, C. E. Helsley
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Pacific geomagnetic secular variation.

Science (New York, N.Y.), 2010
We have considered several different types of records of long-period geomagnetic secular variation: direct measurements made in geomagnetic observatories; paleomagnetic measurements on Hawaiian lava flows with accurately known ages in the interval 0 to 200 years; paleomagentic measurements on Hawaiian lava flows with loosely determined ages within the ...
R R, Doell, A, Cox
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Secular Variations of the Geomagnetic Field in Europe

2009
Geoinformation Issues, 2009, Vol.
Sas-Uhrynowski, Andrzej, Welker, Elżbieta   +1 more
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Secular trends in daily geomagnetic variations

Journal of Atmospheric and Terrestrial Physics, 1980
Abstract After removal of seasonal and sunspot cycle effects, the solar ( S ) and lunar ( L ) daily geomagnetic variations at Hermanus, Huancayo and San Juan are found to have significant secular changes. The solar variations are shown to be more closely fixed to local magnetic coordinates than to geographic coordinates.
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Varying geomagnetic anomalies and secular variation

Journal of Geophysical Research: Solid Earth, 1983
The time variations of the geomagnetic field at 10 European observatories were examined in detail. Fourier analyses were made for three field components at each of the observatories. Curves for each component were synthesized for three passbands: A low passband for periods greater than 30 years, a mid passband for periods equal to or less than 30 years
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Historical Secular Variation and Geomagnetic Theory

1989
The historical record of magnetic observations from AD 1695 has been analyzed to give maps of the magnetic field at the core-mantle boundary for the last 300 yr. These maps have been interpreted qualitatively in terms of a stationary dynamo field with hemispheric symmetry and a pattern of secular variation linked to the base of the solid mantle by ...
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The Geomagnetic Secular Variation in the Ross dependency

New Zealand Journal of Geology and Geophysics, 1963
Abstract The first magnetic observations in the Ross Dependency were made by Sir James Clark Ross in 1840. Since then various expeditions have carried out magnetic measurements, but until the beginning of the International Geophysical Year (IGY) the results were scanty.
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