2nd VERSIM Workshop 2006, Sodankylä, Finland, 26-30 September 2006

Atmospheric Precipitation during Storm-Time Relativistic Electron Flux drop outs

M. A. Clilverd¹, C. J. Rodger², R. M. Millan³, Th.Ulich⁴

¹British Antarctic Survey (NERC), Cambridge, U.K.,
²Dept. of Physics, University of Otago, Dunedin, New Zealand,
³Dept of Physics and Astronomy, Dartmouth College, Hanover, NH, USA,
⁴Sodankylä Geophysical Observatory, Sodankylä, Finland.

Abstract

During the sudden decrease of geosynchronous electron flux (>2 MeV) of 17:10-17:20 UT, January 21, 2005 large-scale precipitation into the atmosphere was observed by the VLF AARDDVARK network (the joint NZ/UK lead Antarctic-Arctic Radiation-belt (Dynamic) Deposition VLF Atmospheric Research Konsortium) and the MINIS balloon experiment. Estimates from ground-based radio propagation experiments at L~5 in the northern and southern hemispheres suggest that the atmospheric precipitation was less than 1/10 of the flux apparently lost during this 10 minute period. However, continuing precipitation losses from 4<L<6, observed for the next 2.7 hours, provides about 1/2 of the total relativistic electron content lost. Similarities and differences in the phenomena observed by MINIS and the AARDDVARK network during this event will be explored.