Results 161 to 170 of about 31,401 (196)

Uncertainty estimates in geomagnetic field modeling

Journal of Geophysical Research: Solid Earth, 1989
Geomagnetic field models usually consist of coefficients of a truncated spherical harmonic analysis derived by a weighted least squares analysis. The data are typically assumed to be uncorrelated, and an estimated, diagonal, data covariance matrix is incorporated as an inverse weighting function. Accuracy estimates on the derived coefficients are taken
R. A. Langel, R. H. Estes, T. J. Sabaka
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Modelling the geomagnetic field

Geophysical Journal International, 1983
Summary. The progress of geomagnetic field modelling is traced from 1600 to the present day, with particular emphasis on the method of spherical harmonic analysis, illustrated by examples taken mainly from British sources. No attempt is made to be comprehensive (a catalogue of models has been given elsewhere by Barraclough) or to include models of ...
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Dynamic geomagnetic field models

Geomagnetism and Aeronomy, 2011
A review of modern dynamic models of the Earth’s magnetosphere (the A2000 paraboloid model and Tsyganenko’s T01 model) is presented. For the magnetic storm of January 9–11, 1997, the results of joint calculations of the magnetospheric magnetic field are presented and contributions of the large-scale magnetospheric currents to the Dst variations are ...
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Mathematical Methods of Geomagnetic Field Modeling

2017
The geomagnetic field, as the Earth’s magnetic field is called, extends from Earth’s interior to outer space. The magnetosphere is the region defined by the areal extent and the shape of the magnetic field of a celestial body, like the planet Earth.
Stavros Kolios, Andrei V. Vorobev, Gulnara R. Vorobeva, Chrysostomos Stylios   +3 more
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A statistical model of the geomagnetic field

pure and applied geophysics, 1964
A statistical model of the geomagnetic field is derived, based on the assumption of an axial geocentric dipole field of strengthHe at the equator perturbed by randomly directed components of constant magnitudeh. The model fits the dispersions found from an analysis of the 1945 field, and the ratioh/He obtained for this field and from the palaeomagnetic
Edward Irving, Martin A. Ward
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Poloidal and toroidal fields in geomagnetic field modeling

Reviews of Geophysics, 1986
The theory of surface operators is described and applied to four surface operators on spheres: the dimensionless surface gradient, ▽1=r▽‐r∂r; the dimensionless surface curl, ; the dimensionless surface Laplacian, ▽1²=▽1 · ▽1; and the Funk‐Hecke operators, integral operators with axisymmetric kernels.
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Bifurcation analysis of chaotic geomagnetic field model

Chaos, Solitons & Fractals, 2017
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Elsonbaty, Amr, Elsadany, A. A.
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Regional geomagnetic field model for Croatia

2015
Geomagnetic components at Croatian repeat stations and ground survey sites, as well as European observatories and repeat stations, were used to obtain a regional geomagnetic model over Croatia at 2009.5 epoch. Different models were derived, depending on input data, and the modelling techniques were Adjusted Spherical Harmonic Analysis and Spherical ...
Vujić, Eugen, Kovács, Peter, Brkić, Mario, Varga, Matej   +3 more
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An Overview of Geomagnetic Field Models

1980
Abstract : Over the last decade, the utility of geomagnetic field models or the mathematical representations of the geomagnetic field has expanded considerably, both for civilian and military applications. Such an increase has been accompanied with more interest in models and demands for better accuracies with resultant changes in techniques of model ...
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Local-Geomagnetic-Field Modeling Improves Directional Surveying

Journal of Petroleum Technology, 2000
This article is a synopsis of paper SPE 56699, "Local-Geomagnetic- Field Modeling Closes the Gap Between MWD and Gyro Directional Surveying," by Tor Inge Waag, Sintef Petroleum Research A/S; Torgeir Torkildsen, Statoil; Odd Helge Inderhaug, Norsk Hydro; and Inge M.
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