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National Space Science Data Center Data set MG-14G |
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NAME: International Geomagnetic Reference Field - 10th Generation |
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SOURCE: |
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Susan Macmillan |
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British Geological Survey |
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West Mains Road |
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Edinburgh EH9 3LA, UK |
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Tel: +44 131 650 0228 |
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Fax: +44 131 668 4368 |
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email: smac@bgs.ac.uk |
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Stefan Maus |
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Colorado Institute for Research in the Environmental Sciences |
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National Geophysical Data Center |
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325 Broadway |
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Boulder, CO 80305-3328 USA |
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Tel: +1 303 497 6522 |
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Fax: +1 303 497 6513 |
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NSSDC CONTACT: |
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D. Bilitza, |
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GSFC/NSSDC |
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code 633/Raytheon, |
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Greenbelt, MD 20771, |
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Fax. (301) 286-1771 |
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bilitza@mail630.gsfc.nasa.gov |
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CONTENT: |
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this file AAREADME.DOC |
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FORTRAN source code: |
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main program (interactive driver) BILCAL.FOR |
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subroutines, functions SHELLIG.FOR |
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BILCAL user manual with examples BILCAL.LOG |
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All in one subroutine igrf_sub.for |
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This file includes SHELLIG.FOR and also a subroutine |
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igrf_sub that computes IGRF parameters. |
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geomagnetic field model coefficients: |
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for 1945 DGRF45.DAT |
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for 1950 DGRF50.DAT |
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for 1955 DGRF55.DAT |
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for 1960 DGRF60.DAT |
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for 1965 DGRF65.DAT |
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for 1970 DGRF70.DAT |
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for 1975 DGRF75.DAT |
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for 1980 DGRF80.DAT |
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for 1985 DGRF85.DAT |
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for 1990 DGRF90.DAT |
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for 1995 DGRF95.DAT |
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for 2000 DGRF00.DAT+ |
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for 2005 IGRF05.DAT+ |
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extrapol. coeff. for 2005-2010 IGRF05S.DAT |
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+ The original IGRF files include coefficients up to order 13. We only use |
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coefficients up to order 10 like in the earlier model generations. The full |
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set of coeffients is in files IGRF00full.DAT and DGRF05full.DAT. Use of the |
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full set requires changes to the software. |
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BRIEF DESCRIPTION: |
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The International Geomagnetic Reference Field (IGRF) model is the |
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empirical representation of the Earth's magnetic field recommended for |
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scientific use by the International Association of Geomagnetism and |
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Aeronomy (IAGA). The IGRF model represents the main (core) field without |
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external sources. They employ the usual spherical harmonics expansion |
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of the scalar potential in geocentric coordinates. The IGRF model |
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coefficients are based on all available data sources including geomagnetic |
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measurements from observatories, ships, aircrafts and satellites. |
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The model consists of coefficient sets from epoch 1945 onward in steps |
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of 5 years and the first time derivatives of the coefficients for a 5-year |
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extrapolation into the future. During the 5-year intervals between consecutive |
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models, linear interpolation is recommended. The IGRF homepage provides access |
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to coefficient files back to 1900. The files up to 1995 provide coefficients |
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up to order 10, for 2000 and 2005 coefficients up to order 13 are provided. |
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Our calculations are limited to using coefficients up to order 10 for all |
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files. |
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In combination with the IGRF coefficient sets different subroutines have |
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been used to determine the components of the magnetic field vector and the |
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L-value at a given location. The NSSDC version uses the subroutines FELDG |
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(magnetic field vector) and SHELLG (L shell) developed by G. Kluge at the |
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European Space Operations Center (ESOC). His use of inverse cartesian co- |
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ordinates simplifies the computation. The IGRF subroutines were developed |
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by A. Zunde of the U.S. Geological Survey (USGS). |
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The program BILCAL produces tables of the geomagnetic field strength, vector |
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components (B-abs., B-north, B-east, B-down, declination, inclination), |
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equatorial/minimum field strength (B0), dipole moment, and L-value in |
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latitude, longitude (geodetic), altitude, or year (decimal). |
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Before using the IGRF please read the 'Health Warning' at |
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http://www.ngdc.noaa.gov/IAGA/wg8/igrfhw.html |
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AVAILABILITY: |
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(1) FORTRAN source code from this directory. |
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(2) Model parameters can be computed and plotted online on IGRFWeb at http://nssdc.gsfc.nasa.gov/space/model/ . |
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(3) Model homepage at http://www.ngdc.noaa.gov/IAGA/wg8/wg8.html . |
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REFERENCES: |
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Peddie, N. W., International Geomagnetic Reference Field: the third |
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generation, J. Geomagn. Geoelectr. 34, 309-326, 1982. |
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Kluge, G., Direct computation of the magnetic shell parameter, |
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Computer Phys. Communications 3, 31-35, 1972. |
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International Geomagnetic Reference Field Revision 1987, J. Geomag. |
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Geoelectr. 39, 773-779, 1987 and EOS Trans. 69, 559, 1988 |
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Langel, R. A., D. R. Barraclough, D. J. Kerridge, V. P. Golovkov, |
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T. J. Sabaka, and R. H. Estes, Definitive IGRF models for 1945, |
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1950, 1955, and 1960, J. Geomag. Geoelectr. 40, 645-702, 1988 |
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Langel, R. A., International Geomagnetic Reference Field, 1991 |
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Revision, J. Geomag. Geoelectr. 43, 1007-1012, 1991 |
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Barton, C.E., Revision of International Geomagnetic Reference Field |
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Released, EOS Trans. 77, #16, April 16, 1996. |
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Barton, C.E., International Geomagnetic Reference Field: The Seventh |
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Generation, J. Geom. Geoelectr. 49, 123-148, 1997. |
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Earth, Planets, and Space Journal, Vol. 52, No. 12, pp. 1117-1233, 2000 |
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M. Mandea et al., International Geomagnetic Reference Field - Epoch 2000 |
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Revision Of The IGRF for 2000 - 2005, http://www.ngdc.noaa.gov/IAGA/wg8/igrf.html, |
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26 May 2000. |
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International Geomagentic Reference Field - 2000, AGU EOS Transactions, |
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pp. 347, Aug 3, 2001 |
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========================================================================= |
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National Space Science Data Center Data set MG-14G |
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========================================================================= |
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