Core surface flow changes associated with the 2017 Pacific geomagnetic jerk

Kathy Whaler, M. D. Hammer, C. C. Finlay, N. Olsen

Research output: Contribution to journalArticlepeer-review

Abstract

A geomagnetic jerk was seen in Swarm satellite data in 2017 over the Pacific region. We invert time series of spatial gradient secular variation data between 2014 and 2020, reduced to a grid of points at satellite altitude, for spatially- and temporally-regularized core surface flow. Pacific region flow acceleration was almost constant before and after the jerk, with a sharp change, especially in the azimuthal component, at the jerk epoch, despite the temporal regularization. Azimuthal acceleration is oppositely signed either side of 160°W, where it effectively vanishes, and also reverses sign at the jerk epoch. Acceleration features drift westward at about 900 km yr−1. Unlike previous studies, the evidence presented here for low latitude waves does not depend on imposing flow equatorial symmetry, quasi- or tangential geostrophy, or band-pass filtering, and has no reliance on stochastic models or numerical simulations.
Original languageEnglish
Article number e2022GL098616
JournalGeophysical Research Letters
Volume49
Issue number15
Early online date18 Jul 2022
DOIs
Publication statusPublished - 16 Aug 2022

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