Local Variations in E- and D-Region Ion Composition Due to Precipitation of Auroral Electrons

Thomas Ulich1, Esa Turunen1, Tuomo Nygrén2, and Kari Kaila2

1Sodankylä Geophysical Observatory, FIN-99600 Sodankylä, Finland
2Dept. of Physical Sciences, University of Oulu, FIN-90570 Oulu, Finland


High time-resolution measurements of electron density in the lower ionosphere are made by the EISCAT incoherent scatter radars. We analyse a series of localised electron precipitation events using the detailed time-dependent Sodankylä Ion Chemistry (SIC) model. We model the time development of the effective recombination coefficient in order to analyse the response of ion and neutral composition to the precipitation. Special attention is paid to the variations of the concentrations of the molecular ions O2+ and NO+.