SM41C-2494
Characteristics of Extreme Geoelectric Fields and Their Possible Causes: Localized Peak Enhancements
Thursday, 17 December 2015
Poster Hall (Moscone South)
Chigomezyo Mudala Ngwira, Catholic University of America, Washington, DC, United States, Antti A Pulkkinen, NASA Goddard Space Flight Center, Greenbelt, MD, United States, Emanuel Bernabeu, PJM Interconnection, Audubon, PA, United States, Jan Eichner, Munich-Re, Munich, Germany, Ari Viljanen, Finnish Meteorological Institute, Helsinki, Finland and Geoffrey Crowley, Atmospheric and Space Technology Research Associates, LLC, Boulder, CO, United States
Abstract:
One of the major challenges pertaining to extreme geomagnetic storms is to understand the basic processes associated with the development of dynamic magnetosphere-ionosphere currents, which generate large induced surface geoelectric fields. Previous studies point out the existence of localized peak geoelectric field enhancements during extreme storms. We examined induced global geoelectric fields derived from ground-based magnetometer recordings for 12 extreme geomagnetic storms between the years 1982--2005. However for the present study, an in-depth analysis was performed for two important extreme storms, October 29, 2003 and March 13, 1989. The primary purpose of this paper is to provide further evidence on the existence of localized peak geoelectric field enhancements, and to show that the structure of the geoelectric field during these localized extremes at single sites can differ greatly from globally and regionally averaged fields. Although the physical processes that govern the development of these localized extremes are still not clear, we discuss some possible causes.
