Large scale campaign for simultaneous measurements of ionospheric conductivity profiles by ELF receivers, incoherent scatter radars, and riometers in Northern Fenno-Scandia

Thomas Ulich1,3, Martin Füllekrug2, Jyrki Manninen3

1Space Physics Group, Dept. of Physical Sciences, University of Oulu, Finland
2Institute of Meteorology and Geophysics, University of Frankfurt, Germany
3Sodankylä Geophysical Observatory, Sodankylä, Finland


Electromagnetic radiation of lighting is partially reflected in the ionosphere. The conductivity of the ionosphere greatly depends on various extra-terrestrial factors, which are commonly summarised as "space weather". The variations of the conductivity lead to temporally variable attenuation of the waves emitted by lightning as well as to changes of their propagation velocities. These can be measured by high-precision ELF receivers and with the aid of numerical models, conductivity profiles can be derived for the ionospheric D region (60-85 km). In order to verify and improve the analytical methods involved, the proposed campaign aims at a simoultaneous measurement of lower ionospheric conductivities with the aid of the EISCAT incoherent scatter radars in Norway, Sweden, and Finland. The results will be compared with measurements of cosmic radio noise absorption by the Finnish Riometer Chain. Furthermore, we will model D-region conductivity by the detailed Sodankylä Ion Chemistry Model (SIC). First tests are planned in conjunction with the Finnish EISCAT Campaign in February 2001. The actual campaign will take place in October 2001.