secular variations

The spatial structure of geomagnetic field secular variations in Europe was examined. Using the data of geomagnetic observatories the new maps of this secular variation (SV) for X, Y, Z, D – components for 5-years intervals 1995-2000 and 2000-2005 were constructed. Their comparison with the IGRM global geomagnetic models was done. The global anomalies – SV-focuses in the structure of the secular variations in Europe were discovered and their kinematics was studied.

Secular variations (SV) of the geomagnetic field at the south and north polar caps are investigated for all observations times. It is shown that secular variations are generated by internal and external origins. It is supposed that internal origins are currents on the mantle – core border and also in tectonosphere and external origins – currents in the magnetosphere and ionosphere. Values SV from external origins depend on solar and geomagnetic activities and from internal origins are decreased.

The determination of the time-dependent constituents of the inertia tensor was considered. Special attention was given to the computation of temporally varying components of the Earth’s inertia tensor, which are based on the time series of 2nd-degree coefficients through GRACE observations.

The paper is devoted to the modelling of the Earth’s fundamental parameters using recent geodetic  and astronomical data in time. The analysis of modern determinations of fundamental parameters of geodesy, astronomy, and geodynamics have led to the development of new closed expressions and the corresponding approach of their adjustment. The secular variations of basic astrogeodetic parameters were estimated.