Instantaneous Pole Velocity and Global Models

TL;DR

This paper introduces a novel method for estimating the Earth's pole velocity using model-calculated horizontal components and Hermite splines, providing a smooth and accurate representation of pole movement over time.

Contribution

It presents a new approach that combines global magnetic field models with spline interpolation to estimate pole velocity from spatial distribution data.

Findings

The method accurately estimates pole velocity between epochs.

It utilizes IGRF and COV-OBSx2 models for horizontal component calculation.

The approach produces smooth velocity trajectories with preserved vector directions.

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.