POGO (8/71) Model Coefficients 1974

Author: R. A. Langel
NASA/GSFC, Code 622
Greenbelt, Maryland 20771

Parameter: Earth's main magnetic field strength and vector

Brief Description:
This data set contains the 240 coefficients of the POGO (8/71) spherical harmonics model of the Earth's main (core) magnetic field. The coefficients are for epoch 1960.0 and extend up to degree and order 10 in the constant and first derivative terms. This is the last in the series of POGO models. It considers field strength data for magnetically quiet conditions through the lifetimes of OGO 2, OGO 4, and OGO 6 (10/65-3/70). In total, more than 50,000 satellite measurements formed the basis for POGO (8/71).

Mead (1979) compared several models including POGO (8/71), AWC (75), IGS (75), and IGRF 1975 with observatory data for the time period 1970 through 1976. POGO (8/71), AWC (75), and IGS (75) showed equally good agreement, whereas IGRF 1975 exhibited a significantly poorer prediction ability. The good results with POGO (8/71) are particularly surprising because only scalar data (field strength) for a restricted time period were used to construct this model, whereas the others are based on much longer data records of scalar and vector data.

R. A. Langel, Near-Earth Disturbances in Total Field at High Latitudes: 1. Summary of Data from OGO 2, 4, and 6, J. Geophys. Res. 79, 2363, 1974.

G. D. Mead, An Evaluation of Recent Internal Magnetic Field Models, in: Quantitative Modeling of Magnetospheric Processes, W. P. Olson (ed.), 110-117, American Geophysical Union, Geophysical Monograph 21, Washington, D.C., 1979.

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