The impact of sudden commencements on ground magnetic field variability: Immediate and delayed consequences
Smith, A.W.; Forsyth, C.; Rae, I.J.; Rodger, C.J.; Freeman, M.P. ORCID: https://orcid.org/0000-0002-8653-8279. 2021 The impact of sudden commencements on ground magnetic field variability: Immediate and delayed consequences. Space Weather, 19 (7), e2021SW002764. 17, pp. 10.1029/2021SW002764
Before downloading, please read NORA policies.Preview |
Text (Open Access)
© 2021. The Authors. 2021SW002764.pdf - Published Version Available under License Creative Commons Attribution 4.0. Download (3MB) | Preview |
Abstract/Summary
We examine how Sudden Commencements (SCs) and Storm Sudden Commencements (SSCs) influence the occurrence of high rates of change of the magnetic field (R) as a function of geomagnetic latitude. These rapid, high amplitude variations in the ground-level geomagnetic field pose a significant risk to ground infrastructure, such as power networks, as the drivers of geomagnetically induced currents. We find that rates of change of ∼ 30 nT min−1 at near-equatorial stations are up to 700 times more likely in an SC than in any random interval. This factor decreases with geomagnetic latitude such that rates of change around 30 nT min−1 are only up to 10 times more likely by 65°. At equatorial latitudes we find that 25% of all R in excess of 50 nT min−1 occurs during SCs. This percentage also decreases with geomagnetic latitude, reaching ≤ 1% by 55°. However, the time period from the SC to three days afterwards accounts for ≥ 90% of geomagnetic field fluctuations over 50 nT min−1, up to ∼ 60° latitude. Above 60°, other phenomena such as isolated substorms account for the majority of large R. Furthermore, the elevated rates of change observed during and after SCs are solely due to those classified as SSCs. These results show that SSCs are the predominant risk events for large R at mid and low latitudes, but that the risk from the SC itself decreases with latitude.
Item Type: | Publication - Article |
---|---|
Digital Object Identifier (DOI): | 10.1029/2021SW002764 |
ISSN: | 1542-7390 |
Additional Keywords: | Sudden Commencements, Geomagnetically Induced Currents, GICs, Interplanetary Shocks, Geomagnetic Perturbations |
Date made live: | 18 Jun 2021 10:43 +0 (UTC) |
URI: | https://nora.nerc.ac.uk/id/eprint/530536 |
Actions (login required)
View Item |
Document Downloads
Downloads for past 30 days
Downloads per month over past year