SPECIAL -- Space Processes and Electrical Changes Influencing Atmospheric Layers

Thomas Ulich1, Norma Crosby2, Kristian Schlegel3, Martin Füllekrug4, and Michael Rycroft4

1Sodankylä Geophysical Observatory, Sodankylä, Finland
2Mullard Space Science Laboratory, University College London, Dorking, Surrey, U.K.
3Max-Planck Institute for Aeronomy, Lindau, Germany
4Institute of Meteorology and Geophysics, University of Frankfurt, Germany
5International Space University, Illkirch-Graffenstaden, France.


The European Science Foundation (ESF) scientific network SPECIAL (Space Processes and Electrical Changes Influencing Atmospheric Layers) has completed its Phase I. The purpose of this network is to investigate mechanisms possibly linking Space Weather and Earth Weather.

Basically, participants are interested in the following three areas: 1.) The AC, and DC, global atmospheric electric current, i.e. charges, currents, and potential differences in the atmosphere, and its electrical conductivity; 2.) Tropospheric and stratospheric responses to energetic charged particle fluxes during well-observed space weather events, and statistical studies of such events; 3.) Sprites and Schumann resonances of the Earth-ionosphere cavity excited by tropical lightning.

A proposal for a Phase II of SPECIAL, where the emphasis will be placed on the assessment of physical processes linking solar activity, magnetospheric variability, clouds, thunderstorms and lightning, was submitted to ESF in December 2000. At the end of Phase II in 2002/03, the members of SPECIAL plan to propose a large-scale European research effort in order to investigate unsolved problems in this context.

Here we shall present some of the achievements of the SPECIAL network that have been obtained up to now. We will focus especially on a large-scale lightning campaign for simultaneous measurements of ionospheric conductivity profiles by ELF receivers, the EISCAT radars, and riometers in Northern Fenno-Scandia. We invite the EISCAT community to actively participate in this effort.