yodaUtility/igrf/00README.TXT

=========================================================================
National Space Science Data Center                       Data set  MG-14G          
=========================================================================

NAME:  International Geomagnetic Reference Field - 10th Generation 

SOURCE:      

Susan Macmillan
British Geological Survey
West Mains Road
Edinburgh EH9 3LA, UK
Tel: +44 131 650 0228
Fax: +44 131 668 4368
email: smac@bgs.ac.uk   

Stefan Maus
Colorado Institute for Research in the Environmental Sciences
National Geophysical Data Center
325 Broadway
Boulder, CO 80305-3328 USA
Tel: +1 303 497 6522
Fax: +1 303 497 6513

NSSDC CONTACT: 
D. Bilitza, 
GSFC/NSSDC 
code 633/Raytheon, 
Greenbelt, MD 20771, 
Fax. (301) 286-1771
bilitza@mail630.gsfc.nasa.gov

CONTENT:     
            this file                           AAREADME.DOC
             FORTRAN source code:  
             main program (interactive driver)   BILCAL.FOR   
             subroutines, functions             SHELLIG.FOR   
                 BILCAL user manual with examples    BILCAL.LOG   
                 All in one subroutine                 igrf_sub.for
                         This file includes SHELLIG.FOR and also a subroutine 
                         igrf_sub that computes IGRF parameters.

             geomagnetic field model coefficients:
             for 1945    DGRF45.DAT    
             for 1950    DGRF50.DAT    
             for 1955    DGRF55.DAT    
             for 1960    DGRF60.DAT    
             for 1965    DGRF65.DAT    
             for 1970    DGRF70.DAT    
             for 1975    DGRF75.DAT    
             for 1980    DGRF80.DAT    
             for 1985    DGRF85.DAT    
             for 1990    DGRF90.DAT    
             for 1995    DGRF95.DAT    
             for 2000    DGRF00.DAT+    
             for 2005    IGRF05.DAT+    
             extrapol. coeff. for 2005-2010      IGRF05S.DAT 
             
 + The original IGRF files include coefficients up to order 13. We only use 
 coefficients up to order 10 like in the earlier model generations. The full 
 set of coeffients is in files IGRF00full.DAT and DGRF05full.DAT. Use of the 
 full set requires changes to the software.
  
BRIEF DESCRIPTION:

The International Geomagnetic Reference Field (IGRF) model is the 
empirical representation of the Earth's magnetic field recommended for 
scientific use by the International Association of Geomagnetism and 
Aeronomy (IAGA). The IGRF model represents the main (core) field without 
external sources. They employ the usual spherical harmonics expansion
of the scalar potential in geocentric coordinates. The IGRF model
coefficients are based on all available data sources including geomagnetic 
measurements from observatories, ships, aircrafts and satellites. 

The model consists of coefficient sets from epoch 1945 onward in steps 
of 5 years and the first time derivatives of the coefficients for a 5-year
extrapolation into the future. During the 5-year intervals between consecutive 
models, linear interpolation is recommended. The IGRF homepage provides access
to coefficient files back to 1900. The files up to 1995 provide coefficients 
up to order 10, for 2000 and 2005 coefficients up to order 13 are provided. 
Our calculations are limited to using coefficients up to order 10 for all
files. 

In combination with the IGRF coefficient sets different subroutines have 
been used to determine the components of the magnetic field vector and the 
L-value at a given location. The NSSDC version uses the subroutines FELDG 
(magnetic field vector) and SHELLG (L shell) developed by G. Kluge at the 
European Space Operations Center (ESOC). His use of inverse cartesian co-
ordinates simplifies the computation. The IGRF subroutines were developed 
by A. Zunde of the U.S. Geological Survey (USGS). 

The program BILCAL produces tables of the geomagnetic field strength, vector 
components (B-abs., B-north, B-east, B-down, declination, inclination), 
equatorial/minimum field strength (B0), dipole moment, and L-value  in  
latitude, longitude (geodetic), altitude, or year (decimal). 

Before using the IGRF please read the 'Health Warning' at 
http://www.ngdc.noaa.gov/IAGA/wg8/igrfhw.html

AVAILABILITY:
(1) FORTRAN source code from this directory.
(2) Model parameters can be computed and plotted online on IGRFWeb at http://nssdc.gsfc.nasa.gov/space/model/ .
(3) Model homepage at http://www.ngdc.noaa.gov/IAGA/wg8/wg8.html .

REFERENCES:

Peddie, N. W., International Geomagnetic Reference Field: the third
   generation, J. Geomagn. Geoelectr. 34, 309-326, 1982.

Kluge, G., Direct computation of the magnetic shell parameter,
   Computer Phys. Communications 3, 31-35, 1972.

International Geomagnetic Reference Field Revision 1987, J. Geomag.
   Geoelectr. 39, 773-779, 1987   and    EOS Trans. 69, 559, 1988

Langel, R. A., D. R. Barraclough, D. J. Kerridge, V. P. Golovkov,
   T. J. Sabaka, and R. H. Estes, Definitive IGRF models for 1945,
   1950, 1955, and 1960, J. Geomag. Geoelectr. 40, 645-702, 1988

Langel, R. A., International Geomagnetic Reference Field, 1991 
   Revision, J. Geomag. Geoelectr. 43, 1007-1012, 1991

Barton, C.E., Revision of International Geomagnetic Reference Field
   Released, EOS Trans. 77, #16, April 16, 1996.

Barton, C.E., International Geomagnetic Reference Field: The Seventh
   Generation, J. Geom. Geoelectr. 49, 123-148, 1997.

Earth, Planets, and Space Journal, Vol. 52, No. 12, pp. 1117-1233, 2000

M. Mandea et al., International Geomagnetic Reference Field - Epoch 2000
   Revision Of The IGRF for 2000 - 2005, http://www.ngdc.noaa.gov/IAGA/wg8/igrf.html,
   26 May 2000.
 
International Geomagentic Reference Field - 2000, AGU EOS Transactions, 
   pp. 347, Aug 3, 2001
   

=========================================================================
National Space Science Data Center                       Data set  MG-14G
=========================================================================
1	=========================================================================
2	National Space Science Data Center Data set MG-14G
3	=========================================================================
4
5	NAME: International Geomagnetic Reference Field - 10th Generation
6
7	SOURCE:
8
9	Susan Macmillan
10	British Geological Survey
11	West Mains Road
12	Edinburgh EH9 3LA, UK
13	Tel: +44 131 650 0228
14	Fax: +44 131 668 4368
15	email: smac@bgs.ac.uk
16
17	Stefan Maus
18	Colorado Institute for Research in the Environmental Sciences
19	National Geophysical Data Center
20	325 Broadway
21	Boulder, CO 80305-3328 USA
22	Tel: +1 303 497 6522
23	Fax: +1 303 497 6513
24
25	NSSDC CONTACT:
26	D. Bilitza,
27	GSFC/NSSDC
28	code 633/Raytheon,
29	Greenbelt, MD 20771,
30	Fax. (301) 286-1771
31	bilitza@mail630.gsfc.nasa.gov
32
33	CONTENT:
34	this file AAREADME.DOC
35	FORTRAN source code:
36	main program (interactive driver) BILCAL.FOR
37	subroutines, functions SHELLIG.FOR
38	BILCAL user manual with examples BILCAL.LOG
39	All in one subroutine igrf_sub.for
40	This file includes SHELLIG.FOR and also a subroutine
41	igrf_sub that computes IGRF parameters.
42
43	geomagnetic field model coefficients:
44	for 1945 DGRF45.DAT
45	for 1950 DGRF50.DAT
46	for 1955 DGRF55.DAT
47	for 1960 DGRF60.DAT
48	for 1965 DGRF65.DAT
49	for 1970 DGRF70.DAT
50	for 1975 DGRF75.DAT
51	for 1980 DGRF80.DAT
52	for 1985 DGRF85.DAT
53	for 1990 DGRF90.DAT
54	for 1995 DGRF95.DAT
55	for 2000 DGRF00.DAT+
56	for 2005 IGRF05.DAT+
57	extrapol. coeff. for 2005-2010 IGRF05S.DAT
58
59	+ The original IGRF files include coefficients up to order 13. We only use
60	coefficients up to order 10 like in the earlier model generations. The full
61	set of coeffients is in files IGRF00full.DAT and DGRF05full.DAT. Use of the
62	full set requires changes to the software.
63
64	BRIEF DESCRIPTION:
65
66	The International Geomagnetic Reference Field (IGRF) model is the
67	empirical representation of the Earth's magnetic field recommended for
68	scientific use by the International Association of Geomagnetism and
69	Aeronomy (IAGA). The IGRF model represents the main (core) field without
70	external sources. They employ the usual spherical harmonics expansion
71	of the scalar potential in geocentric coordinates. The IGRF model
72	coefficients are based on all available data sources including geomagnetic
73	measurements from observatories, ships, aircrafts and satellites.
74
75	The model consists of coefficient sets from epoch 1945 onward in steps
76	of 5 years and the first time derivatives of the coefficients for a 5-year
77	extrapolation into the future. During the 5-year intervals between consecutive
78	models, linear interpolation is recommended. The IGRF homepage provides access
79	to coefficient files back to 1900. The files up to 1995 provide coefficients
80	up to order 10, for 2000 and 2005 coefficients up to order 13 are provided.
81	Our calculations are limited to using coefficients up to order 10 for all
82	files.
83
84	In combination with the IGRF coefficient sets different subroutines have
85	been used to determine the components of the magnetic field vector and the
86	L-value at a given location. The NSSDC version uses the subroutines FELDG
87	(magnetic field vector) and SHELLG (L shell) developed by G. Kluge at the
88	European Space Operations Center (ESOC). His use of inverse cartesian co-
89	ordinates simplifies the computation. The IGRF subroutines were developed
90	by A. Zunde of the U.S. Geological Survey (USGS).
91
92	The program BILCAL produces tables of the geomagnetic field strength, vector
93	components (B-abs., B-north, B-east, B-down, declination, inclination),
94	equatorial/minimum field strength (B0), dipole moment, and L-value in
95	latitude, longitude (geodetic), altitude, or year (decimal).
96
97	Before using the IGRF please read the 'Health Warning' at
98	http://www.ngdc.noaa.gov/IAGA/wg8/igrfhw.html
99
100	AVAILABILITY:
101	(1) FORTRAN source code from this directory.
102	(2) Model parameters can be computed and plotted online on IGRFWeb at http://nssdc.gsfc.nasa.gov/space/model/ .
103	(3) Model homepage at http://www.ngdc.noaa.gov/IAGA/wg8/wg8.html .
104
105	REFERENCES:
106
107	Peddie, N. W., International Geomagnetic Reference Field: the third
108	generation, J. Geomagn. Geoelectr. 34, 309-326, 1982.
109
110	Kluge, G., Direct computation of the magnetic shell parameter,
111	Computer Phys. Communications 3, 31-35, 1972.
112
113	International Geomagnetic Reference Field Revision 1987, J. Geomag.
114	Geoelectr. 39, 773-779, 1987 and EOS Trans. 69, 559, 1988
115
116	Langel, R. A., D. R. Barraclough, D. J. Kerridge, V. P. Golovkov,
117	T. J. Sabaka, and R. H. Estes, Definitive IGRF models for 1945,
118	1950, 1955, and 1960, J. Geomag. Geoelectr. 40, 645-702, 1988
119
120	Langel, R. A., International Geomagnetic Reference Field, 1991
121	Revision, J. Geomag. Geoelectr. 43, 1007-1012, 1991
122
123	Barton, C.E., Revision of International Geomagnetic Reference Field
124	Released, EOS Trans. 77, #16, April 16, 1996.
125
126	Barton, C.E., International Geomagnetic Reference Field: The Seventh
127	Generation, J. Geom. Geoelectr. 49, 123-148, 1997.
128
129	Earth, Planets, and Space Journal, Vol. 52, No. 12, pp. 1117-1233, 2000
130
131	M. Mandea et al., International Geomagnetic Reference Field - Epoch 2000
132	Revision Of The IGRF for 2000 - 2005, http://www.ngdc.noaa.gov/IAGA/wg8/igrf.html,
133	26 May 2000.
134
135	International Geomagentic Reference Field - 2000, AGU EOS Transactions,
136	pp. 347, Aug 3, 2001
137
138
139	=========================================================================
140	National Space Science Data Center Data set MG-14G
141	=========================================================================