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Core Surface Flow Changes Associated With the 2017 Pacific Geomagnetic Jerk
K A Whaler1, M D Hammer2, C C Finlay2
1School of GeoSciences University of Edinburgh Edinburgh UK.
Geophysical Research Letters
|October 17, 2022
Summary
A 2017 geomagnetic jerk event over the Pacific caused a sharp change in core surface flow acceleration, particularly the azimuthal component. This acceleration reversal and westward drift provide new insights into Earth's magnetic field dynamics.
Area of Science:
- Geophysics
- Earth's Magnetic Field
- Satellite Geodesy
Background:
- Geomagnetic jerks are rapid changes in Earth's magnetic field.
- The Swarm satellite mission provides crucial data for studying these phenomena.
Purpose of the Study:
- To analyze core surface flow changes associated with a 2017 geomagnetic jerk.
- To investigate the spatial and temporal characteristics of flow acceleration.
Main Methods:
- Inversion of time series secular variation data from Swarm satellite.
- Spatially and temporally regularized core surface flow reconstruction.
- Analysis of flow acceleration components and their variations.
Main Results:
- A significant change in azimuthal flow acceleration occurred during the 2017 geomagnetic jerk.
- Azimuthal acceleration reversed sign across 160°W and at the jerk epoch.
- Observed westward drift of acceleration features at approximately 900 km/year.
- Evidence for low-latitude waves was obtained without prior assumptions on flow symmetry or filtering.
Conclusions:
- The 2017 geomagnetic jerk significantly impacted core surface flow dynamics.
- The study provides robust evidence for low-latitude wave phenomena in the core.
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