USGS Model Coefficients for Continental U.S. and Hawaii 1985
N. W. Peddie
Denver Federal Center, Mail Stop 964
U. S. Geological Survey
Denver, Colorado 80225
Parameter: Geomagnetic field parameters for the continental U.S. and Hawaii
Availability: On line at USGS; can be accessed via the toll free number (800) 358-2663 ( 279-2062 in Colorado); modem should be for 300 or 1200 baud (full duplex, no parity).
These models were developed at the U.S. Geological Survey (USGS) and describe the direction and intensity of the magnetic field in the United States at the beginning of 1985 and the rate of change expected for the next years. The models were derived from several tens of thousands of original field measurements from land, marine, and aerial surveys; from values synthesized with the International Geomagnetic Reference Field (IGRF) for 1985; and from recent data from magnetic observatories and repeat stations. The models are in the form of a spherical harmonics series up to degree and order 4 (24 coefficients) for the continental states and of degree and order 2 (eight coefficients) for Hawaii. Computation of geomagnetic field values is part of the USGS Online Information System, which can be accessed from a remote terminal.