Special Issue: Geomagnetic Field Modelling and IGRF 2000
- Open Access
An estimate of the errors of the IGRF/DGRF fields 1945–2000
Earth, Planets and Space volume 52, pages 1207–1211 (2000)
The IGRF coefficients inevitably differ from the true values. Estimates are made of the their uncertainties by comparing IGRF and DGRF models with ones produced later. For simplicity, the uncertainties are summarized in terms of the corresponding root-mean-square vector uncertainty of the field at the Earth’s surface; these rms uncertainties vary from a few hundred to a few nanotesla. (It is assumed that the IGRF is meant to model the long-wavelength long-period field of internal origin, with no attempt to separate the long-wavelength fields of core and crustal origin; the models are meant for users interested in the field near and outside the Earth’s surface, not for core-field theoreticians.) So far we have rounded the main-field coefficients to 1 nT; this contributes an rms vector error of about 10 nT. If we do in fact get a succession of vector magnetic field satellites then we should reconsider this rounding level. Similarly, for future DGRF models we would probably be justified in extending the truncation from n = 10 to n = 12. On the other hand, the rounding of the secular variation coefficients to 0.1 nT could give a false impression of accuracy.
Cain, J. C., Z. Wang, D. R. Schmitz, and J. Meyer, The geomagnetic spec trum for 1980 and core-crustal separation, Geophys. J., 97, 443–447, 1989.
Golovkov, V. P., T. N. Bondar, and I. A. Burdelnaya, Spatial-temporal modeling of the geomagnetic field for 1980–2000 period and a candidate IGRF secular-variation model for 2000–2005, Earth Planets Space, 52, this issue, 1125–1135, 2000.
Langel, R. A. and R. H. Estes, A geomagnetic field spectrum, Geophys. Res. Lett., 9, 250–253, 1982.
Langel, R. A., R. H. Estes, and T. J. Sabaka, Uncertainty estimates in geo magnetic field modelling, J. Geophys. Res., 94, 12,281–12,299, 1989.
Langlais, B. and M. Mandea, An IGRF candidate main geomagnetic field model for epoch 2000 and asecular variation model for 2000–2005, Earth Planets Space, 52, this issue, 1137–1148, 2000.
Lowes, F. J., Mean-square values on sphere of spherical harmonic vector fields, J. Geophys. Res., 71, 2179, 1966.
Macmillan, S. and J. M. Quinn, The 2000 revision of the joint UK/US geomagnetic field models and an IGRF 2000 candidate model, Earth Planets Space, 52, this issue, 1149–1162, 2000.
Sabaka, T. J., R. A. Langel, R. T. Baldwin, and J. A. Conrad, The geomagnetic field 1900–1995, including the large-scale field from magnetospheric sources, and the NASA candidate models for the 1995 revision of the IGRF, J. Geomag. Geoelectr., 49, 157–206, 1997.
About this article
Cite this article
Lowes, F.J. An estimate of the errors of the IGRF/DGRF fields 1945–2000. Earth Planet Sp 52, 1207–1211 (2000). https://doi.org/10.1186/BF03352353
- Secular Variation
- Earth Planet Space
- Truncation Level
- Geomagnetic Jerk
- Secular Variation Model