Determination of the IGRF 2000 model

Abstract

The IGRF 2000 has been estimated from magnetic measurements taken by the Ørsted sattelite in summer 1999. For this purpose, three models have been derived: The first two models were estimated using a few geomagnetic quiet days in May and September 1999, respectively. The third model, called Oersted(10c/99), was derived from scalar data spanning six months and vector data spanning four months. In order to get a model for epoch 2000.0, the IGRF 95 secular variaion model has been applied to the data. The IGRF 2000 model was taken to be the internal degree/order 10 portion of Oersted(10c/99). We describe the data selection, model parameterization, parameter estimation and an evaluation of the three models. Copy right© The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences.