Statistics of geomagnetically induced currents
(Ari Viljanen)

Objective

To understand how well conventional geomagnetic indices characterise the activity of GIC (geomagnetically induced currents).

Exercise outline

GIC is caused by rapid variations of the geomagnetic field, which means that the time derivative of the magnetic field is evidently a good activity indicator. A simple "DB indicator" has been recently introduced to describe the regional GIC activity. Traditional magnetic indices in turn characterise amplitudes of variations and apparently emphasise different aspects than DB. In this exercise, the ionospheric IE index (regional variant of the global AE index) and the magnetospheric Dst index will be used for the years 1994-2004. The following tasks should be considered:
- Illustrate the indices using high-resolution data of the October 2003 storm
- Derive statistics of DB, IE and Dst (daily averages)
- Calculate correlations between all pairs of DB, IE and Dst.
- If appropriate, refine the analysis by considering only a subset of events, for example, only stormy days.
- Discuss other possibilities for a more quantitative study.

Data

  • Dst index: OMNIWeb
  • IE index (variant of the global AE index): to be provided by Ari Viljanen
  • DB indicator (1982-2005)
  • High-resolution GIC and geomagnetic data of October 29-31, 2003: to be provided by Ari Viljanen.

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Contact course assistant:
Minna Palmroth_at_fmi.fi (replace _at_ with @)
Finnish Meteorological Institute, Space Research
Erik Palmenin aukio 1, (Dynamicum)
Room 1D11a, 09-1929 4696
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