Jan 11, 2017 · 5.02.3.2.1 The international geomagnetic reference field Probably the most used models are those from the IGRF/DGRF series, regularly published by the International Association of Geomagnetism and Aeronomy (IAGA). Those are (mostly empirical) representations of the slowly changing large-scale part of the field of internal origin. Their maximum degree used to be N = 10, but this was changed to ...

Apr 15, 1989 · An Evaluation of the New IGRF and DGRF Candidate Models Based on Marine Magnetic Anomalies in the North Atlantic.

Oct 1, 1987 · Abstract The candidate models for the definitive geomagnetic reference field (DGRF) for the years 1945, 1950, 1955 and 1960—S45, 50, 55, 60, SFA45, 50, 55, 60, SFAS45, 50, 55, 60, and BGSMF50, 60—are evaluated using magnetic observatory data and observatory anomaly solutions given by the CSFC (9/80) and GSFC (12/83) models. The results indicate that the series of SFA models is the most ...

Apr 15, 1989 · Definitive magnetic reference field (DGRF) evaluation based on marine magnetic anomalies. Phys. Earth Planet. Inter., 54: 332-339. When compiling magnetic data that have been collected over several decades, the accuracy of the magnetic reference fields that are used to reduce the data to a common datum-level becomes an important factor.

Jan 1, 1997 · The magnetic anomaly map of east and southeast Asia was produced by compiling manydata sets collected by air-borne and ship-borne surveys. In order to tie between adjoining areas, DGRF-RGRF removal and a linear shift were applied to each data set. Linear features are detected from the map as a special reference to suggest possible crustal ...

Feb 1, 1992 · The fourth revision replaced the models for 1945, 1950, 1955 and 1960 with DGRF models (IAGA, 1988). For dates between the epochs of the DGRF models, linear interpolation between the coefficients with epochs bracketing the date is to be used. The linear interpolation 0031-9201/92/$05.00 1992 Elsevier Science Publishers B.V.

Mar 17, 2013 · The predictive secular variation model that had been used in the previous five years is then also abandoned, and simply replaced by an interpolation between this DGRF model (DGRF 2000) and the latest IGRF model (IGRF 2005), for the period between those two models (while, of course, the new secular variation model published with the new IGRF is ...

Sep 1, 1985 · The DGRF/IGRF-80 series (Peddie, 1982) is a sequence of coefficients for epochs 1965, 1970, 1975, and 1980 plus secular change terms predic- ting the field from 1980 to 1985.

Jan 1, 1985 · For- tunately the DGRF itself was a weighted mean of the 3 candidate models, the NASA weight varying from 20% in 1965 to 30% in 1975, so for these epochs the DGRF will contain spurious fields of magnitude 70 nT in the equatorial region, contrib- uting 10 nT r.m.s. to …

Oct 1, 1987 · The candidate models for the definitive geomagnetic reference field (DGRF) for the years 1945, 1950, 1955 and 1960—S45, 50, 55, 60, SFA45, 50, 55, 60,…