P. T. Verronen1, A. Seppälä1, E. Turunen2, V. I. Shematovich3, D. V. Bisikalo3, Th. Ulich2, and E. Kyrölä1
1 Finnish Meteorological Institute, Geophysical Research,
P.O. Box 503, FIN-00101 Helsinki, Finland.
2 Sodankylä Geophysical Observatory, Tähteläntie 62, FIN-99600 Sodankylä, Finland.
3 Institute of Astronomy of the Russian Academy of Sciences, 48 Pyatnitskaya str., Moscow, 109017, Russia.
The CHAMOS study was started as a response to ESA's Envisat-1 Announcement of Opportunity. The basic idea is to study how energetic particle events affect the chemistry and composition of the middle atmosphere. CHAMOS combines ion chemistry modelling with satellite and ground instrument measurements. See the CHAMOS WWW pages at http://www.geo.fmi.fi/~ptv/chamos/ for more information.
We have studied how ion chemistry and secondary electrons contributes to the odd nitrogen (i.e. N and NO) production during solar proton events. We found that a significant amount of odd nitrogen can be produced through ion chemistry and that the contribution of secondary electrons can vary significantly with altitude. Recently, we compared our modelling results with satellite measurements of nitric oxide and ozone.