Geomagnetic jerks in the polar regions

Abstract

The occurrence of geomagnetic jerks over the Arctic and Antarctic regions is here investigated. Maps of geomagnetic secular acceleration over the polar regions are produced from the CM4 and CHAOS models and the occurrence of geomagnetic jerks is associated with jumps in secular acceleration. The obtained results confirm that in Antarctica geomagnetic jerks systematically follow geomagnetic jerks in the Arctic region with a time delay from one to three years. Evidence is found of an abrupt change in secular acceleration in both polar regions around 1985, suggesting that the 1985 local jerk could actually be a worldwide event. Combining our results with the results previously obtained on the occurrence of a geomagnetic jerk at low-mid latitudes around 2003, we support the hypothesis of a global extension of an event occurred at the beginning of the 21st century.