Earth Planets Space, Vol. 52 (No. 12), pp. 1149-1162, 2000
S. Macmillan1 and J. M. Quinn2
1British Geological Survey, Murchison House, West Mains Road, Edinburgh, EH9 3LA, Scotland
2United States Geological Survey, MS 966, Federal Center, Denver, CO 80225-0046, U.S.A.
(Received February 21, 2000; Revised June 27, 2000; Accepted July 8, 2000)
Abstract: The method of derivation of the joint UK/US spherical harmonic geomagnetic main-field and secular-variation models is presented. Early versions of these models, with the main field truncated at degree 10, are the UK/US candidates for the IGRF 2000 model. The main-field model describes the Earth's magnetic field at the 2000.0 epoch, while the secular-variation model predicts the evolution of this field between 2000.0 and 2005.0. A revised 1995.0 main-field model was also generated. Regional models for the continental US, Alaska and Hawaii were also produced as a by-product of the UK/US global modelling effort.