Modeling the Effects of Energetic Particle Precipitation on Middle Atmosphere

Pekka Verronen1, Esa Turunen2, Thomas Ulich2, and Erkki Kyrölä1

1Finnish Meteorological Institute, Geophysical Research, P.O. Box 503, FIN-00101 Helsinki, Finland
2Sodankylä Geophysical Observatory, Tähteläntie 112, FIN-99600 Sodankylä, Finland


Solar proton events (SPE) and electron precipitation affect the middle atmosphere constituent concentrations. Ionization caused by precipitating particles leads to enhanced production of some minor neutral constituents (such as NO) through reaction chains in which ionic reactions play an important role. Therefore, when calculating the effects of particle precipitation on the atmosphere and ionosphere, one must take into account the reactions that couple the ionic and neutral constituents.

Finnish Meteorological Institute and Sodankylä Geophysical Observatory have developed a detailed ion and neutral chemistry model of the middle atmosphere that can be used to investigate the effect of particle events on several minor constituents. Our steady state model, which is based on the Sodankylä Ion Chemistry model, contains 56 ion species, the most important neutral species, and over 300 chemical reactions.

We will present our model and the preliminary modeling results of energetic particle precipitation effects on middle atmosphere.