Models of the geomagnetic field on the territory of the Republic of Macedonia

The aim of this paper is to present various geomagnetic field models of Macedonia based on measurements at repeat stations as well as satellite data covering this region. At first a theoretical basis of the geomagnetic field, spherical cap harmonical model and polynomial model will be given. Аttention will be paid to input data used in the modelling process, in particular the data reduction techniques using neighbouring geomagnetic observatories as well as criteria for data selection of Oersted, CHAMP and SAC-C satellite missions. The spherical cap harmonical analysis model was developed over the Balkan Peninsula with the Republic of Macedonia as central position for a spherical cap of 8o. The polynomial model on the other hand was based on ground-based data at 15 repeat stations reduced to sea level for epochs 2003.5 and 2004.5. This enabled geomagnetic field maps based on model calculations to be obtained for the country. A comparative analysis of these two models showed a satisfied degree of correlation, with the polynomial model more suitable for the territory of the Republic of Macedonia