Signs of a new geomagnetic jerk between 2019 and 2020 from Swarm and observatory data

F Javier Pavón-Carrasco,Santiago Marsal,J Miquel Torta,Saioa A Campuzano

doi:10.1186/s40623-021-01504-2

F Javier Pavón-Carrasco, Santiago Marsal + Show 2 more

Open Access

https://doi.org/10.1186/s40623-021-01504-2

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Abstract

Following the observed pattern of a new geomagnetic jerk every 3–4 years, certain predictions suggested that a new event should occur around 2020 after the one observed around 2017.5. In this work, we explore this scenario by analysing the secular variation of the East geomagnetic field component in both ground and satellite geomagnetic data. At ground, we use the available data from 2015 to 2021 in 10 observatories worldwide distributed. This analysis shows the occurrence of the mentioned jerk in mid-2017 at observatories located in the Pacific region, but also reveals a new jerk between mid-2019 and early 2020 with a clear global character. Swarm satellite data also corroborate these findings by means of the secular variation estimated using virtual observatories at 440 km altitude. In addition, a general view using the most recent CHAOS geomagnetic model confirms the global character of the 2020-jerk with V-shaped secular variation changes in meridional sectors covering the Eastern Pacific, America, Asia and the Indian Ocean; and Λ-shapes in Europe, Africa and Western Pacific. The radial geomagnetic field at the core–mantle boundary is investigated as the origin of the new jerk. Results show that the global-average secular acceleration of the radial field exhibits a new pulse at mid-2018, establishing the starting epoch of the 2020-jerk.

Highlights

Since late 2013, the European Space Agency’s Swarm mission (Friis-Christensen et al 2006) has provided accurate measurements of the geomagnetic field hundreds of kilometres above the Earth’s surface
Conclusions the geomagnetic main field exhibits a complex behaviour in both space and time, whose detailed generating processes remain difficult to establish, recent studies indicate that its small-scale variation is driven by wave oscillations at the core–mantle boundary
These waves suggest a periodic pattern of 3–4 years in the secular acceleration of the field that modulates the occurrence of geomagnetic jerks

Summary

Introduction

Since late 2013, the European Space Agency’s Swarm mission (Friis-Christensen et al 2006) has provided accurate measurements of the geomagnetic field hundreds of kilometres above the Earth’s surface. – A very recent geomagnetic field model indicates the global character of the new jerk. The ultimate support and confirmation of the occurrence of the jerk involves the use of satellite data, which is materialized by means of global geomagnetic field models.

Results

Conclusion