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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-24 7:11 |
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Conference: Bucharest University Faculty of Physics 2008 Meeting
Section: Atmosphere and Earth Science; Environment Protection
Title:
The diurnal variation of geomagnetic field recorded at the European observatories (POSTER)
Authors:
A. Patroi, I. Vasile
Affiliation:
Institute of Geodynamics, Bucharest, Romania,
E-mail
venera@geodin.ro
Keywords:
geomagnetic field,diurnal variation,ionosphere
Abstract:
The geomagnetic field is varying at all scales, both spatially and temporally. In time, its period spectrum comprises a bandwidth between fractions of a second and several hundred years, with amplitudes from fractions of nT (nanoTesla) to several hundred nT, and in space, at the Earth surface the field varies between 3 and 7x104 nT. Generally, about 95-97% of the measured geomagnetic field is generated inside the Earth (the main field, produced by a dynamo process in the external core, the crustal field, related to the distribution of rocks with magnetic properties, the induced field in crust and mantle by variations of the external field and of the main field). The rest, of 3-5% has its origin outside the Earth, being produced by magnetospheric and ionospheric current systems. The diurnal variation of the geomagnetic field is produced by a dynamo process in the E region of the ionosphere (80 – 130 km altitude).The minute values of the geomagnetic elements X, Y, and Z from 20 European geomagnetic observatories, during the time interval June 20-27, 2005, were processed to show the diurnal variation. Several characteristics of the diurnal variation of the geomagnetic field recorded in the network of European observatories are discussed.
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