REVISION OF THE IGRF: A Summary Report on the Zmuda Memorial Conference on Geomagnetic Field Models

Geophysics ◽  
1975 ◽  
Vol 40 (5) ◽  
pp. 907-908
Author(s):  
Robert D. Regan ◽  
Joseph C. Cain
Keyword(s):  
Geomagnetic Field ◽  
Field Model ◽  
Reference Field ◽  
Summary Report ◽  
International Geomagnetic Reference Field ◽  
Colorado Springs ◽  
International Geomagnetic Reference ◽  
Geomagnetic Field Models ◽  
American Geophysical ◽  
American Geophysical Union

On March 24 and 25, 1975, the Zmuda Memorial Field Model Conference cosponsored by the Society of Exploration Geophysicists (SEG) was held at the Broadmoor Hotel, in Colorado Springs, Colorado. This meeting was designed to provide an opportunity for dialogue between those who derive geomagnetic field models and the various users and to serve as an opportunity to discuss the plans for the proposed revision of the International Geomagnetic Reference Field Model (IGRF). The conference included an objective appraisal of the use of field models in magnetic surveys and documented the need for a more accurate reference field. This report summarizes the conference results as they pertain to the members of SEG. A complete summary, including abstracts, is published in the July (1975) issue of EOS, Transactions of the American Geophysical Union.

The current status of the IGRF and its relation to magnetic surveys

Geophysics ◽  
1983 ◽  
Vol 48 (7) ◽  
pp. 997-998 ◽  
Author(s):  
Robert D. Regan
Keyword(s):  
Geomagnetic Field ◽  
Working Group ◽  
International Association ◽  
Current Status ◽  
Reference Field ◽  
Summary Report ◽  
International Geomagnetic Reference Field ◽  
Significant Time ◽  
International Geomagnetic Reference ◽  
Geomagnetic Field Models

As aeromagnetic surveys covered increasingly larger areas and as the need arose for the compilation of adjacent surveys with significant time differences, there has been an increase in the use of geomagnetic field models for regional field definition. Indeed, few aeromagnetic contracts exist today without some provision for removal of the International Geomagnetic Reference Field (IGRF). Yet, as publications indicate (Regan and Cain, 1975a, 1975b; Reford et al, 1976; Regan, 1977, 1978), the IGRF is far from perfect for this application despite the considered attention of the IAGA (International Association of Geomagnetism and Aeronomy) working group charged with its upkeep and maintenance. One reason for this is that the model is meant to serve all areas of geomagnetism and, as such, is not specifically tailored to the needs of the exploration community. The recent summary report of the IAGA committee (Peddie, 1982) could lead to some confusion because there are seven IGRF models published. A rational question for those involved in aeromagnetic surveys is “Which model should be used for regional field definition?”

scholarly journals Bulgarian Geomagnetic Reference Field (BulGRF) for 2015.0 and secular variation prediction model up to 2020

2017 ◽  
Vol 35 (5) ◽  
pp. 1085-1092
Author(s):  
Metodi Metodiev ◽  
Petya Trifonova
Keyword(s):  
Secular Variation ◽  
Geomagnetic Field ◽  
Field Model ◽  
Field Measurements ◽  
Reference Field ◽  
Main Field ◽  
Close Match ◽  
Secular Variation Model ◽  
Geomagnetic Field Models ◽  
Annual Means

Abstract. The Bulgarian Geomagnetic Reference Field (BulGRF) for 2015.0 epoch and its secular variation model prediction up to 2020.0 is produced and presented in this paper. The main field model is based on the well-known polynomial approximation in latitude and longitude of the geomagnetic field elements. The challenge in our modelling strategy was to update the absolute field geomagnetic data from 1980.0 up to 2015.0 using secular measurements unevenly distributed in time and space. As a result, our model gives a set of six coefficients for the horizontal H, vertical Z, total field F, and declination D elements of the geomagnetic field. The extrapolation of BulGRF to 2020 is based on an autoregressive forecasting of the Panagyurishte observatory annual means. Comparison of the field values predicted by the model with Panagyurishte (PAG) observatory annual mean data and two vector field measurements performed in 2015 shows a close match with IGRF-12 values and some difference with the real (measured) values, which is probably due to the influence of crustal sources. BulGRF proves to be a reliable alternative to the global geomagnetic field models which together with its simplicity makes it a useful tool for reducing magnetic surveys to a common epoch carried out over the Bulgarian territory up to 2020.

AD HOC COMMITTEE ON MAGNETIC FIELD MODELS

Geophysics ◽  
1976 ◽  
Vol 41 (4) ◽  
pp. 796-797
Keyword(s):  
Magnetic Field ◽  
Working Group ◽  
Ad Hoc ◽  
Field Model ◽  
International Association ◽  
Geological Survey ◽  
Reference Field ◽  
International Geomagnetic Reference Field ◽  
International Geomagnetic Reference ◽  
Purdue University

An SEG ad‐hoc committee on Magnetic Field Models was formed as one result of the Zmuda Memorial Field Model Conference (Regan and Cain, 1975a). The chairman of the committee is Michael S. Reford, Geoterrex Ltd., and committee members are William J. Hinze, Purdue University, Peter J. Hood, Geological Survey of Canada, and Robert D. Regan, U.S. Geological Survey. The main objective of the committee was to produce an SEG resolution on the revision of the International Geomagnetic Reference Field (IGRF) to be submitted to the International Association of Geomagnetism and Aeronomy’s (IAGA) working group 1.1.

scholarly journals Geomagnetic core field models and secular variation forecasts for the 13th International Geomagnetic Reference Field (IGRF-13)

2020 ◽  
Author(s):  
Ingo Wardinski ◽  
Diana Saturnino ◽  
Hagay Amit ◽  
Aude Chambodut ◽  
Benoit Langlais ◽  
...  
Keyword(s):  
Secular Variation ◽  
Geomagnetic Field ◽  
Singular Spectrum Analysis ◽  
Reference Field ◽  
Candidate Model ◽  
Main Field ◽  
International Geomagnetic Reference Field ◽  
Core Field ◽  
International Geomagnetic Reference ◽  
Continuous Models

Abstract Observations of the geomagnetic field taken at Earth's surface and at satellite altitude were combined to construct continuous models of the geomagnetic field and its secular variation from 1957 to 2020. From these parent models, we derive candidate main field models for the epochs 2015 and 2020 to the 13th generation of the International Geomagnetic Reference Field (IGRF). The secular variation candidate model for the period 2020 - 2025 is derived from a forecast of the secular variation in 2022.5, which results from a multi-variate singular spectrum analysis of the secular variation from 1957 to 2020.

International Geomagnetic Reference Field 1980 A Report by IAGA Division I, Working Group I

Geophysics ◽  
1982 ◽  
Vol 47 (5) ◽  
pp. 841-842 ◽  
Author(s):  
Norman W. Peddie
Keyword(s):  
Secular Variation ◽  
Working Group ◽  
Field Model ◽  
International Association ◽  
Division I ◽  
Reference Field ◽  
Main Field ◽  
International Geomagnetic Reference Field ◽  
International Geomagnetic Reference ◽  
Group I

IGRF 1965, the first international geomagnetic reference field, was adopted by the International Association of Geomagnetism and Aeronomy (IAGA) in 1968 (IAGA Commission 2, Working Group 4, 1969). It consists of a model of the main field at 1965.0, along with a model of secular variation for use in extending the main field model in time, both backward (not earlier than 1955.0) and forward (not later than 1975.0). IGRF 1975, adopted later, consists of IGRF 1965 extended to 1975.0, along with a revised model of secular variation for use in extending the main field model up to 1980.0 (IAGA Division I Study Group, 1976).

International Geomagnetic Reference Field Revision 1987

Geophysics ◽  
1988 ◽  
Vol 53 (4) ◽  
pp. 576-578 ◽  
Author(s):  
D. R. Barraclough
Keyword(s):  
Charged Particle ◽  
Mathematical Models ◽  
Secular Variation ◽  
Spherical Harmonic ◽  
Geomagnetic Field ◽  
Magnetic Anomalies ◽  
Reference Field ◽  
International Geomagnetic Reference Field ◽  
International Geomagnetic Reference ◽  
Field Revision

The International Geomagnetic Reference Field (IGRF) is a series of mathematical models of the main geomagnetic field and its secular variation, the models consisting of sets of spherical harmonic (or Gauss) coefficients. The IGRF has become a widely used means of deriving values of geomagnetic field components in, for example, studies of magnetic anomalies and investigations of charged particle motions in the ionosphere and the magnetosphere.

scholarly journals International Geomagnetic Reference Field: the thirteenth generation

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
P. Alken ◽  
E. Thébault ◽  
C. D. Beggan ◽  
H. Amit ◽  
J. Aubert ◽  
...  
Keyword(s):  
Field Model ◽  
International Association ◽  
Rate Of Change ◽  
Generation Model ◽  
Reference Field ◽  
Main Field ◽  
International Geomagnetic Reference Field ◽  
Group V ◽  
International Geomagnetic Reference ◽  
Time Period

AbstractIn December 2019, the International Association of Geomagnetism and Aeronomy (IAGA) Division V Working Group (V-MOD) adopted the thirteenth generation of the International Geomagnetic Reference Field (IGRF). This IGRF updates the previous generation with a definitive main field model for epoch 2015.0, a main field model for epoch 2020.0, and a predictive linear secular variation for 2020.0 to 2025.0. This letter provides the equations defining the IGRF, the spherical harmonic coefficients for this thirteenth generation model, maps of magnetic declination, inclination and total field intensity for the epoch 2020.0, and maps of their predicted rate of change for the 2020.0 to 2025.0 time period.

scholarly journals THE USE OF GEOMAGNETIC FIELD MODELS IN MAGNETIC SURVEYS

Geophysics ◽  
1975 ◽  
Vol 40 (4) ◽  
pp. 621-629 ◽  
Author(s):  
Robert D. Regan ◽  
Joseph C. Cain
Keyword(s):  
Numerical Model ◽  
Secular Variation ◽  
Geomagnetic Field ◽  
Harmonic Series ◽  
Magnetic Survey ◽  
Reference Field ◽  
Main Field ◽  
International Geomagnetic Reference Field ◽  
Spherical Harmonic Series ◽  
Geomagnetic Field Models

Global geomagnetic field models, usually computed from spherical harmonic series, are becoming more important in the reduction of magnetic surveys. When used correctly, a numerical model of sufficient complexity, including adequate secular variation correction, provides a suitable representation of the regional field. The best known and most widely used of the available field models is the International Geomagnetic Reference Field (IGRF). However, the IGRF may not be suitable for the reduction of all magnetic survey data because of its imperfect fit to the main field, particularly since 1968.

Periodic solutions and stability analysis of electrodynamic tethers for 13 degree international geomagnetic reference field

2018 ◽  
Vol 233 (11) ◽  
pp. 4115-4128
Author(s):  
Yu-wei Yang ◽  
Hong Cai
Keyword(s):  
Periodic Solutions ◽  
Dynamic Equation ◽  
Geomagnetic Field ◽  
Floquet Theory ◽  
Failure Time ◽  
Reference Field ◽  
International Geomagnetic Reference Field ◽  
Orbital Inclination ◽  
International Geomagnetic Reference ◽  
Free Parameters

The geomagnetic field plays a crucial role in the operation of the electrodynamic tether system in the space. Using the 13 degree International Geomagnetic Reference Field to model the geomagnetic field, the libration dynamic equation of the system is established. The nonlinear libration dynamic equation of the system is a typical chaotic system. In the dynamic equation, there are four free parameters: the orbital inclination, the orbital eccentricity, the altitude of the perigee and the electrodynamic parameter. After adding dummy control terms into the dynamic system, the extended time delayed autosynchronization control method is employed to calculate the periodic solutions of the dynamic equation. The shapes and amplitudes of the periodic libration motions change with the free parameters regularity. Based on the Floquet theory, the stabilities of the periodic solutions are analyzed. The orbit time during which the initial periodic libration turns to the rotation motion is defined as the failure time. It is used to measure the instability of the periodic solution and validate the results from the Floquet theory. Simulations show that the results from the failure time are consistent with the results from the Floquet theory. For all parameters, the periodic solutions are all unstable. In addition, the relationships between the instabilities of the periodic solutions and the free parameters are obtained.

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