Geomagnetic field analysis-V. Determining steady core-surface flows directly from geomagnetic observations
نویسندگان
چکیده
منابع مشابه
Recent Geodynamo Simulations and Observations of the Geomagnetic Field
[1] In 1995, two groups [Kageyama et al., 1995; Glatzmaier and Roberts, 1995a, 1995b] reported results of numerical integrations of fully three-dimensional, fully nonlinear dynamos. Their papers were precursors of a stream of such models that have focused particularly on the geodynamo. They provide us, in unprecedented detail, with spectacular realizations of interesting geomagnetic field behav...
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S U M M A R Y The maximum entropy technique is an accepted method of image reconstruction when the image is made up of pixels of unknown positive intensity (e.g. a grey-scale image). The problem of reconstructing the magnetic field at the core–mantle boundary from surface data is a problem where the target image, the value of the radial field Br, can be of either sign. We adopt a known extensio...
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The geomagnetic field at the Earth’s surface is determined by a large number of current sources, internal and external, which vary at overlapping time scales. As a result, the time variation of the field, ranging from nHz to tens of Hz, can be modeled as a multifractal whose properties depend on frequency and activity level, with the latter being largely determined by the external driving due t...
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[1] We present four new records of the Iceland Basin Excursion (IBE) and five new records of the Laschamp Excursion (LE) obtained from rapidly deposited marine sediments in the North Atlantic Ocean, the Nordic Seas, the Gulf of Mexico, the South China Sea, and the southern Indian Ocean. Marked minima in relative paleointensity correspond with the paleomagnetic directional changes associated wit...
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Extreme variations of Earth's magnetic field occurred in the Levant region around 1000 BC, when the field intensity rapidly rose and fell by a factor of 2. No coherent link currently exists between this intensity spike and the global field produced by the core geodynamo. Here we show that the Levantine spike must span >60° longitude at Earth's surface if it originates from the core-mantle bound...
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ژورنال
عنوان ژورنال: Geophysical Journal International
سال: 1995
ISSN: 0956-540X,1365-246X
DOI: 10.1111/j.1365-246x.1995.tb03556.x