AbstractImpulsive geomagnetic field disturbances are an important aspect of the geomagnetic storm environment for electric power grids and other ground-based infrastructures that can be impacted by geomagnetically induced currents (GIC). Significant power grid impacts in present day networks have been observed at relatively low levels of intensity, for example the Quebec grid blackout during the March 1989 storm occurred at a peak intensity of ∼480nT/min and permanent damage to large power transformers have occurred at even lower intensity levels. An analysis of both contemporary and historic storm data and records indicates dBh/dt impulsive disturbances larger than 2000nT/min have been observed at latitudes of concern for power grid infrastructures. In extreme scenarios available data suggests that disturbance levels as high as ∼5000nT/min may have occurred during the great geomagnetic storm of May 1921. A comparative evaluation of this storm using morphology-based techniques indicates that large electrojet intensifications exceeding those observed during the March 1989 superstorm were present, further that the Dst range for the May 1921 storm could be as much as −900nT or ∼50% larger than the March 1989 Dst ranking which is the largest on record.
Great geomagnetic storms and extreme impulsive geomagnetic field disturbance events – An analysis of observational evidence including the great storm of May 1921
Advances in Space Research ; 38 , 2 ; 188-199
2005-08-09
12 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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