Model of the MAGSAT magnetic anomaly field over Europe using spherical capharmonic analysis

Based on the MAGSAT magnetic anomaly fields over Europe and the adjacent ar eas spherical cap models have been derived. The method of spherical cap har monic analysis, due to Haines (1985), has been applied for the modelling of the MAGSAT magnetic anomalies. The data set used in the analysis included the 1 degrees x 1 degrees gridded values of the MAGSAT anomaly fields betwe en latitudes phi = 6 degrees to 60 degrees N and longitudes lambda = 19 deg rees W to 70 degrees E. The pole of the cap is at phi = 33 degrees N and la mbda = 26 degrees E and its half-angle is 40 degrees. The maximum index (K- m,) of the model is 18 and the total number of model coefficients is 361. A minimum wavelength corresponding to this index at the Earth's surface is s imilar to 1000 km. The RMS deviations between the calculated and observed v alues are similar to 4 nT for Delta X, similar to 3 nT for Delta Y, and 3,5 nT for Delta Z respectively. The spherical cap harmonic model was used for the construction of magnetic anomaly maps for all components and at differ ent altitudes. (C) 1999 Elsevier Science Ltd. All rights reserved.