Crustal field recovery and secular variation from regional and global models over Albania

Abstract

The static geomagnetic field of crustal origin is optionally calculated bythe recent global geomagnetic field models. However, their description in global scale tends to miss some local characteristics. The same can be inferred for the rate of the geomagnetic field changes i.e. secular variation (SV). In order to depict some particularity of crustal field in local scale for small region like as Albania, two regional models are constructed: one based on the Legendre’s polynomials and the other based on a linear approximation. Both models use data from different measurement campaigns in the Albanian repeat stations and few data from neighbourhood countries. The residuals produced by these models and by the recent global models: EMM2015, POMME – 9 and CM5 are calculated and compared. The SV from regional and global models following standard procedures are also calculated. Substantial differences between SV calculated by global models and regional models are observed.