THE 1995 REVISION OF THE JOINT US UK GEOMAGNETIC-FIELD MODELS .2. MAIN FIELD/

This paper presents the 1995 main-field revision of the World Magnetic Model (WMM-95). It is based on Project MAGNET high-level (greater tha n or equal to 15,000 ft.) vector aeromagnetic survey data collected be tween 1988 and 1994 and on scalar total intensity data collected by th e Polar Orbiting Geomagnetic Survey (FOGS) satellite during the period 1991 through 1993. The spherical harmonic model produced from these d ata describes that portion of the Earth's magnetic field generated int ernal to the Earth's surface at the 1995.0 Epoch. When combined with t he spherical harmonic model of the Earth's secular variation described in paper I, the Earth's main magnetic field is fully characterized be tween the years 1995 and 2000. Regional magnetic field models for the conterminous United States, Alaska and, Hawaii were generated as by-pr oducts of the global modeling process.