Ground geomagnetic field and GIC response to March 17, 2015, storm

Abstract

The St. Patrick's Day geomagnetic storm on March 17, 2015, has been chosen by the space community for synergetic analysis to build a more comprehensive picture of the storm's origin and evolution. This storm had an unusually long (~ 17 h) main phase. During this period, many substorm-like activations occurred. These activations resulted in bursts of geomagnetically induced currents (GICs) in power lines on the Kola peninsula. To examine the substorm activations in more detail, we apply various data processing techniques for the worldwide array of magnetometers: the virtual magnetograms, magnetic latitude-local time (MLT) snapshots, and magnetic keograms. These techniques are simple tools that are supplementary to more advanced facilities developed for the analysis of SuperDARN, IMAGE, and CARISMA arrays. We compare the global spatial localization and time evolution of the geomagnetic X-component disturbance and magnetic field variability measured by the Hilbert transform of time derivative dB/dt. The latitude-MLT mapping of these magnitudes shows that very often a region with highest magnetic variability does not overlap with a substorm "epicenter" but is shifted to its poleward or equatorward boundaries. Highest variability of the geomagnetic field, and consequently intense GICs, are caused by medium-scale fast varying structures. There is no one-to-one correspondence between substorm intensity and GIC magnitude.

A global climatological model of extreme geomagnetic field fluctuations

“…A subsequent analysis of twelve large geomagnetic storms by Ngwira et al (2013) confirmed that this latitude threshold was associated with the limited equatorward expansion of the Auroral Electrojet (AEJ). The most extreme ionospheric currents are likely to be associated with substorm expansions along auroral arcs near the edge of the auroral bulge and this interpretation was recently supported by Kozyreva et al (2018) who examined a number of substorms associated with the March 2015 geomagnetic storm, observing that the maximum 1-min fluctuations occurred near the edges of the auroral electrojets, the location for which were inferred from the magnitude of the change in B N . The bulk movement of ionospheric current systems may weaken assumptions of stationarity in the tail distributions of jdB H =dtj.…”

“…In previous studies, EVT has been used to examine the likelihood of extreme values of geomagnetic indices including D st (Silbergleit, 1996;Tsubouchi & Omura, 2007), the Auroral Electrojet indices (AU, AL, and AE) (Nakamura et al, 2015), A p (Koons, 2001), and the aa and AA* indices (Siscoe, 1976;Silbergleit, 1999), although the location and timing of large jdB H =dtj events are not well predicted by geomagnetic index statistics (e.g., Kozyreva et al, 2018). In related space weather fields, EVT has characterised the probability of extreme solar flare X-ray flux (Elvidge & Angling, 2018;Tsiftsi & De la Luz, 2018) and extreme high-energy (>2 MeV) radiation-belt "killer" electron fluxes (Koons, 2001;O'Brien et al, 2007;Meredith et al, 2015).…”

“…Space Weather Space Clim. 2020, 10, 5 EVT and other statistical approaches have been applied to the prediction of extreme jdB H =dtj in several previous publications (Thomson et al, 2011;Love et al, 2016;Nikitina et al, 2016;Wintoft et al, 2016) and individual case studies have examined extreme jdB H =dtj characteristics (e.g., Viljanen et al, 2001;Pulkkinen et al, 2012;Ngwira et al, 2013, Kozyreva et al, 2018. In Section 3 of this paper, we present a new assessment based on a significantly larger dataset than presented in these earlier studies -1.9 billion field measurements from 125 magnetometers worldwide.…”

Transient Oscillations Near the Dayside Open‐Closed Boundary: Evidence of Magnetopause Surface Mode?

“…The profile has been augmented at high latitudes with station NRD from the Greenland East Coast array. The band‐integrated spectral power from latitudinally distributed stations in a running 20‐min window has been used to construct a magnetic “keogram” showing time evolution of the latitudinal distribution of ULF power in a given frequency band (Kozyreva et al, ). A discrete station location imposes an inevitable error in the determination of ULF power peak latitudes, about ΔΦ~1°.…”

Nighttime Magnetic Perturbation Events Observed in Arctic Canada: 2. Multiple‐Instrument Observations

“…These events can induce large geoelectric fields and geomagnetically-induced currents that can have harmful effects on electrical power grids. Nighttime perturbation events have often been associated with magnetic storms and auroral substorm onsets, but several studies have suggested that other, more localized magnetospheric and/or ionospheric processes, including poleward auroral expansions and small-scale ionospheric current vortices, also may drive these events [Viljanen, 1997;Pulkkinen et al, 2003;Huttunen et al, 2002;Ngwira et al, 2015Ngwira et al, , 2018Belakhovsky et al, 2018;Kozyreva et al, 2018, andDimmock et al, 2019].…”