This data set consists of the 462 coefficients for the GSFC (9/80) geomagnetic field model. The model is based on (i) 15,206 MAGSAT vector observations (November 5-6, 1979, same as used in MGST (6/80)), (ii) 71,000 OGO scalar observations (same as used in POGO [8/71] plus 24,000 additional data), (iii) measurements from 148 magnetic observatories, (iv) 300 marine measurements, (v) approximately 600 measurements from selected repeat stations. The coefficients are for epoch 1980.0 and extend to degree and order 13 in the constant and first derivative terms, 6 in the second derivative terms, and 4 in the third derivative terms. The time span of the data and of the model is 1960 through 1980. GSFC (9/80) constitutes a significant improvement over earlier models because of the enlarged data base and because the ground observations were corrected for crustal (anomaly) fields. Langel et al. (1982) compared GSFC (9/80) with MGST (6/80), AWC (75), and two other models. GSFC (9/80) shows a consistently closer agreement with the measurements than the other models over the whole 20-year time period. The software package includes a subroutine for calculation of the magnetic field strength and vector components.
R. A. Langel, R. H. Estes, and G. D. Mead, Some New Methods in Geomagnetic Field Modeling Applied to the 1960-1980 Epoch, J. Geomag. Geoelectr. 34, 327, 1983.