American Geophysical Union Become an AGU Member
Subscribe to AGU Journals		 AGU Home AGU Publications

Read Full Article (file size: 1651674 bytes)    Cited by

SPACE WEATHER, VOL. 6, S07001, doi:10.1029/2008SW000388, 2008

Statistics of extreme geomagnetically induced current events

A. Pulkkinen

Goddard Earth Sciences and Technology Center, University of Maryland, Baltimore County, Baltimore, Maryland, USA
NASA Goddard Space Flight Center, Greenbelt, Maryland, USA


R. Pirjola

Geophysical Research Division, Finnish Meteorological Institute, Helsinki, Finland


A. Viljanen

Geophysical Research Division, Finnish Meteorological Institute, Helsinki, Finland


Abstract

In this work, space weather events associated with extreme geoelectric field and geomagnetically induced current (GIC) magnitudes are investigated. The geoelectric field and consequent GIC are computed using geomagnetic field recordings over an extended time period and ground conductivity and technological system configurations favorable for large GIC. The statistics are derived for both overall occurrence of the geoelectric field and geoelectric field occurrence conditioned by the state of the magnetosphere and the solar wind. It is shown that in high-latitude areas having resistive ground conductivity structures and in systems having characteristics favorable for large GIC, GIC amplitudes of about 200 A can be expected to occur 102–103 times (in 10-s values) per year while GIC of about 2000 A occur only 10–100 times in 100 years. On the basis of the Dst index and the solar wind electric field values derived by Siscoe et al. (2006) and Tsurutani et al. (2003), it is estimated by means of derived conditional probability distributions that although magnitudes of about 10 V/km are possible, the most probable value for the maximum magnitude of the geoelectric field during the Carrington event of 1–2 September 1859 is about 4 V/km. The usage of derived conditional probabilities in space weather applications is also discussed.

Received 11 January 2008; accepted 24 April 2008; published 4 July 2008.

Keywords: extreme events; geomagnetically induced currents.

Index Terms: 2722 Magnetospheric Physics: Forecasting (7924, 7964); 2788 Magnetospheric Physics: Magnetic storms and substorms (7954); 7959 Space Weather: Models; 7904 Space Weather: Geomagnetically induced currents.

Read Full Article (file size: 1651674 bytes)    Cited by

Citation: Pulkkinen, A., R. Pirjola, and A. Viljanen (2008), Statistics of extreme geomagnetically induced current events, Space Weather, 6, S07001, doi:10.1029/2008SW000388.