The geomagnetic field in Croatia

Abstract

 In this study we present the distribution of the geomagnetic field com­po­nents: declination (D), horizontal intensity (H), inclination (I), total field in­tensity (F), as well as the crustal and anomaly geomagnetic fields over the region of Croatia for the 2003.76 epoch, calculated using the Comprehensive model CM4 (Sabaka et al., 2004).

The smooth change of D, H, I and F values over the whole territory is found. The map of the crustal field reveals symmetric north-south and east-­west isolines behaviour, with the minimum value in the middle part of the north Croatia. The highest values are found at the Adriatic see, along all the coast and at the very eastern part of the country. The anomalies are every­where negative, with the smallest values in the north-east of Croatia.

The predicted annual secular variation for the Croatian region is: 0.06 °/year for D, 11 nT/year for H, 0.02 °/year for I and 50 nT/year for F.

In order to get an insight in the structure of the local field and determine the best location for the observatory, we made use of a set of intensity data measured over the northern part of middle Croatia in 2003. The obtained detailed anomaly map reveals weak small-scale negative structure (–40 nT in average).

Predicted crustal and anomaly fields suggest that the best place for the observatory would be in the middle northern part of Croatia, what is further constrained with the anomalies obtained on the surveyed area.

With the present study we aim to pave a way for more detail research in the field of geomagnetism in Croatia, which has commenced again after more than 50 years’ gap.