Earth Planets Space, Vol. 52 (No. 12), pp. 1175-1182, 2000
Nils Olsen1, Terence J. Sabaka2, and Lars Tøffner-Clausen3
1Danish Space Research Institute, Juliane Maries Vej 30, DK - 2100 Copenhagen Ø, Denmark
2Raytheon ITSS, Lanham, MD 20706, U.S.A.
3Ørsted Science Data Center, DMI, Lyngbyvej 100, DK - 2100 Copenhagen Ø, Denmark
(Received February 25, 2000; Revised July 7, 2000; Accepted July 12, 2000)
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.