Spherical harmonic models of the geomagnetic field

  • 66 Pages
  • 0.44 MB
  • English
H.M.S.O. , London
Geomagnetism -- Mathematical models., Spherical harmo
Statement[by] D. R. Barraclough.
SeriesGeomagnetic bulletin ;, 8, Geomagnetic bulletins of the Institute of Geological Sciences ;, 8.
ContributionsInstitute of Geological Sciences (Great Britain), Natural Environment Research Council (Great Britain)
LC ClassificationsQC815.2 .B38
The Physical Object
Pagination[2], 66 p. ;
ID Numbers
Open LibraryOL4491747M
ISBN 100118812696
LC Control Number79321559

Get this from a library. Spherical harmonic models of the geomagnetic field. [D R Barraclough; Institute of Geological Sciences (Great Britain); Natural Environment Research Council (Great Britain)]. 11th Generation International Geomagnetic Reference Field.

Schmidt semi-normalized spherical harmonic coefficients are listed. Coefficients for degrees n = 1, 13 in units of nanotesla are listed for IGRF and definitive DGRF main field models. Coefficients for degrees n= 1,8 in units of nT yr −1 are listed for the predictive secular by: Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from the Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the magnetic field is generated by electric currents due to the motion of convection currents of a mixture of molten iron and nickel in the Earth's outer core: these.

The Spherical Cap Harmonic Analysis concept was introduced in in the context of geomagnetism as a local or regional extension of the classic global spherical harmonic analysis.

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Starting from the basic principles in which the analysis method is founded, this paper describes the latest applications for the modeling of the main magnetic Cited by: adshelp[at] The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86AAuthor: N.

Benkova, T. Cherevko. 7 rows  Geomagnetic field models are conveniently represented as spherical harmonic expansions of. The CHAOS-4 geomagnetic field model. spherical harmonic models of the Earth’s lithospheric field. In the. sequential approach, a-priori models of all known magnetic field.

The geomagnetic field gradient tensor from the analysis of spherical harmonic field models, such as the eccentric anticyclonic gyre. is then what one refers to as a geomagnetic field model.

Spherical harmonic analysis of the geomagnetic secular variation A review of methods. Phys. Earth Planet. Inter., Methods of producing spherical harmonic models of the secular variation of the geomagnetic field are reviewed and classified, more emphasis being given to modern by: Spherical harmonic analysis is the procedure of representing a potential function by a sum of spherical harmonic functions.

E.,Non-uniqueness of the external geomagnetic field determined by surface intensity measurements, Jour. Geophys. R.,Spherical Harmonic Models of the Geomagnetic Field, Geomagnetic Bulletin 8. models are the series of recent GFZ high-precision geomagnetic core field models that rely on satellite magnetic field measurements, in particular on calibrated Swarm and CHAMP vector field and ground observatory data.

The coefficients of the spherical harmonic expansion is represented in snapshots and the temporal evolution between the snapshots is realised through Spherical harmonic models of the geomagnetic field book interpolation. The intrinsic ability of the method of spherical cap harmonic analysis to separate external and internal sources allows the calculation of equivalent ionospheric and induced currents that are able to explain variations of the geomagnetic field over a portion of the earth's by: The Dilts method for computing spherical harmonic expansion coefficients of a surface function ƒ(θ, ϕ) is adapted to the inverse and forward problems of geomagnetic main-field modeling.

This method, which takes full advantage of the intrinsic speed of the fast Fourier transform (FFT), can compute the coefficients of a typical degree and order 12 model in just a few seconds on most main Cited by: 3.

Spherical Harmonics. The IGRF models the geomagnetic field → (,) as a gradient of a magnetic scalar potential (,) → (,) = − ∇ (,) The magnetic scalar potential model consists of the Gauss coefficients which define a spherical harmonic expansion of (,) = ∑ = ∑ = + (() ⁡ + ⁡) (⁡)where is radial distance from the Earth's center, is the maximum degree of the expansion.

analysis of the geomagnetic field due to its importance in controlling the trajectories of cosmic rays and lower energy charged particles trapped in the magnetosphere. on the region from altitudes to 60, Krp, spherical harmonic repre- sentations of the geomagnetic. The magnetic field at 15 observatories for the smaller area can be computed to an rms residual of only 7 nT for all three components using two sets of rectangular harmonic coefficients and the AWC/75 world chart model.

Rectangular harmonic analysis and spherical harmonic analysis are by: Spherical-harmonic analyses of American and Soviet isomagnetic charts for An integration method is developed from Poisson's integral, and for it, a new surface grid based on a spherical icosahedron's subdivisions.

Also discussed are the chang Cited by: THE USE OF GEOMAGNETIC FIELD MODELS IN MAGNETIC SURVEYS* Robert D. Regan** Joseph C. Cain*** ABSTRACT Global geomagnetic field models, usually computed from spherical harmonic series, are becoming of increased im-portance in the reduction of magnetic surveys.

When used correctly, a numerical model of sufficient complexity, in. Abstract. We consider the problem of describing the ancient magnetic field as completely as possible using paleomagnetic data.

One of the best ways to do this is to represent the field by the use of Gauss coefficients. Unlike ordinary cases, however, spherical harmonic analysis Cited by: Global spherical harmonic models of the internal magnetic field of the Moon based on sequential and coestimation approaches Michael E.

Purucker1 and Joseph B. Nicholas1 Abstract. Three new models of the global internal magnetic field of the Moon based on Lunar Prospector (LP) fluxgate magnetometer observations are developed for use in. Buy Geomagnetic Observations and Models (IAGA Special Sopron Book Series) This volume provides comprehensive and authoritative coverage of all the main areas linked to geomagnetic field observation, from instrumentation to methodology, on ground or near-Earth.

Efforts are also focused on a 21st century e-Science approach to open access to Author: M. Mandea. Mathematically, the Earth's magnetic field is normally described by a spherical harmonic expansion, a series of special spherical functions of latitude/longitude and their associated coefficients.

Each group of functions describes a particular field pattern: the first three terms describe the field of a dipole; the next 5 terms describe a. The 12th generation of the International Geomagnetic Reference Field (IGRF) was adopted in December by the Working Group V-MOD appointed by the International Association of Geomagnetism and Aeronomy (IAGA).

It updates the previous IGRF generation with a definitive main field model for epocha main field model for epochand a linear annual predictive Cited by: On modeling magnetic fields on a sphere with dipoles and quadrupoles.

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Relations with spherical harmonic analysis —————————— 9 This paper assists in the understanding of the global geomagnetic field as it is manifested in models slightly more complex than theCited by: 4. Dipole approximations of the geomagnetic field. Introduction; The centred dipole model; The eccentric dipole model; References; Introduction.

It is customary to express the geomagnetic field as the gradient of a scalar potential function V is usually expressed as an orthogonal expansion in spherical harmonics.

We introduce a system of orthogonal Cartesian coordinates (x, y, z) with. The call requested candidate models for the main field (MF) for the Definitive Geomagnetic Reference Field for epoch (DGRF), for a provisional IGRF model for epoch (IGRF) both to spherical harmonic (SH) deg and for a prediction of its annual rate of change, the secular variation (SV), over the upcoming 5 years (SV Cited by: Conventional spherical harmonic analysis for regional modelling of the geomagnetic field Conventional spherical harmonic analysis for regional modelling of the geomagnetic field De Santis, Angelo Spherical Harmonic Analysis (SHA) is normally used to model the three‐dimensional global geomagnetic field.

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To address the same problem in regional modelling, Haines ( According to the geomagnetic observation data in China for from geomagnetic stations and 35 geomagnetic observatories, and the geomagnetic data of 38 IGRF calculated points in China's adjacent.

MAGMAP: Mapping Spherical Harmonic Models of the Geomag Field Robert L. Parker This program can evaluate a magnetic field model, specified as a set of spherical harmonic coefficients,atanindividual point, or on a grid in several different map program requires a single input diskfile con.

This study opens a way to describe in detail regional geomagnetic main field and its secular variation. Keywords: Geomagnetic field, secular variation, regional modelling, spherical cap harmonic analyses, comprehensive models. Introduction The terrestrial magnetic field is a very complex system with contributions from different sources.

The International Geomagnetic Reference Field (IRGF) is a model describing the core field from to The latest version was produced by an international team of scientists, including several from our team, under the auspices of the International Association of Geomagnetism and Aeronomy (IAGA).Global spherical harmonic models of the internal magnetic field of the Moon based on sequential and coestimation approaches Michael E.

Purucker1 and Joseph B. Nicholas1 Received 13 May ; revised 19 July ; accepted 20 August ; published 10 December [1] Three new models of the global internal magnetic field of the Moon based on.POMME is a scientific main field model representing the geomagnetic field in the region from the Earth's surface to an altitude of a couple of thousand kilometers.

The time variations of the internal field are given by a piece-wise linear representation of the spherical harmonic (Gauss) coefficients of .