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TitleNighttime magnetic perturbation events observed in Arctic Canada: 1. survey and statistical analysis
AuthorEngebretson, M J; Pilipenko, V A; Ahmed, L Y; Posch, J L; Steinmetz, E S; Moldwin, M B; Connors, M G; Weygand, J M; Mann, I R; Boteler, D HORCID logo; Russell, C T; Vorobev, A V
SourceJournal of Geophysical Research, Space Physics 2019 p. 1-17, Open Access logo Open Access
Alt SeriesNatural Resources Canada, Contribution Series 20190177
PublisherAmerican Geophysical Union (AGU)
Mediapaper; on-line; digital
File formatpdf (Adobe® Reader®); html
ProvinceNunavut; Quebec; Manitoba
NTS25; 26; 35; 36; 37; 45; 46; 47; 54; 55; 56
AreaCanadian Arctic; Baffin Island; Melville Peninsula; Ungava Peninsula; Hudson Bay; Repulse Bay; Rankin Inlet; Churchill; Cape Dorset; Pangnirtung; Igloolik
Lat/Long WENS -96.0000 -64.0000 70.0000 58.0000
Subjectsgeophysics; Science and Technology; Nature and Environment; geomagnetic fields; geomagnetism; geomagnetic variations; magnetic field; statistical analyses; magnetometer surveys; magnetic storms; Infrastructures
Illustrationslocation maps; tables; time series; scatter diagrams; histograms; geoscientific sketch maps; plots
ProgramPublic Safety Geoscience Assessing space weather hazards
Released2019 08 28
AbstractThe rapid changes of magnetic fields associated with large, isolated magnetic perturbations with amplitudes delta-B of hundreds of nanotesla and 5- to 10-min periods can induce bursts of geomagnetically induced currents that can harm technological systems. This paper presents statistical summaries of the characteristics of nightside magnetic perturbation events observed in Eastern Arctic Canada from 2014 through 2017 using data from stations that are part of four magnetometer arrays: MACCS, AUTUMNX, CANMOS, and CARISMA, covering a range of magnetic latitudes from 68 to 78°. Most but not all of the magnetic perturbation events were associated with substorms: roughly two thirds occurred between 5 and 30 min after onset. The association of intense nighttime magnetic perturbation events with magnetic storms was significantly reduced at latitudes above 73°, presumably above the nominal auroral oval. A superposed epoch study of 21 strong events at Cape Dorset showed that the largest dB/dt values appeared within an ~275-km radius that was associated with a region of shear between upward and downward field-aligned currents. The statistical distributions of impulse amplitudes of both delta-B and dB/dt fit well the log-normal distribution at all stations. The delta-B distributions are similar over the magnetic latitude range studied, but the kurtosis and skewness of the dB/dt distributions show a slight increase with latitude. Knowledge of the statistical characteristics of these events has enabled us to estimate the occurrence probability of extreme impulsive disturbances using the approximation of a log?normal distribution.

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