Instantaneous Pole Velocity and Global Models

Abstract

A new approach to estimating the velocity of the pole moving is considered. The method uses the model-calculated spatial distribution of the (vector) horizontal component \textbf{H} for a given year and its change relative to the closest epochs. The velocity equation is obtained from the expression for the time dependence of the position of the pole $\mathbf{H}(\lambda(t),\phi(t),t)=0$. Here $\lambda(t)$ and $\phi(t)$ are the geographic coordinates of the pole at time $t$. The velocity between epochs can be found using the Hermite spline, which gives a smooth line that keeps the velocity vector in each epoch. We use IGRF and COV-OBSx2 models to find the horizontal component.