Recent north magnetic pole acceleration towards Siberia caused by flux lobe elongation

TL;DR

The paper explains the recent acceleration of Earth's north magnetic pole towards Siberia as a result of flux lobe elongation caused by changes in core flow, predicting continued pole movement in the near future.

Contribution

It identifies the flux lobe elongation on the core-mantle boundary as the cause of pole acceleration, linking core flow alterations to surface magnetic pole dynamics.

Findings

Pole has accelerated towards Siberia since 1990.

Flux lobe elongation weakened the Canadian lobe's surface signature.

Pole expected to move an additional 390-660 km towards Siberia in the next decade.

Abstract

The wandering of Earth's north magnetic pole, the location where the magnetic field points vertically downwards, has long been a topic of scientific fascination. Since the first in-situ measurements in 1831 of its location in the Canadian arctic, the pole has drifted inexorably towards Siberia, accelerating between 1990 and 2005 from its historic speed of 0-15 km/yr to its present speed of 50-60 km/yr. In late October 2017 the north magnetic pole crossed the international date line, passing within 390 km of the geographic pole, and is now moving southwards. Here we show that over the last two decades the position of the north magnetic pole has been largely determined by two large-scale lobes of negative magnetic flux on the core-mantle-boundary under Canada and Siberia. Localised modelling shows that elongation of the Canadian lobe, likely caused by an alteration in the pattern of core-flow between 1970 and 1999, significantly weakened its signature on Earth's surface causing the pole to accelerate towards Siberia. A range of simple models that capture this process indicate that over the next decade the north magnetic pole will continue on its current trajectory travelling a further 390-660 km towards Siberia.