1Finnish Meteorological Institute, Geophysical Research,
P.O. Box 503, FIN-00101 Helsinki, Finland
2Sodankylä Geophysical Observatory,
Tähteläntie 112, FIN-99600 Sodankylä, Finland
Abstract
The ionization by solar UV-radiation and energetic particle precipitation causes variation in upper atmosphere constituent concentrations. Ionization and chemical reactions lead to a production of odd nitrogen in the mesosphere, which is important to the ozone balance of the atmosphere. Under polar night conditions the nitric oxides are long lived and can be carried down into the lower atmosphere, where they destruct stratospheric ozone.
Three European satellite missions, Envisat-1, Ørsted, and Odin, will be launched in next two years. Together with the EISCAT incoherent scatter radars and a network of other ground measurements they will provide a so far unique possibility to address this scientific problem in the auroral region. Several trace gas monitoring satellite instruments will cover the mesosphere as well as the stratosphere on a global scale. The GOMOS and MIPAS instruments will be launched onboard European Space Agency's Envisat-1 satellite. GOMOS is a stellar occultation spectrometer that will measure O3, NO2, NO3, O2, H2O, air, aerosol, and temperature profiles. MIPAS is a limb interferometer that will measure O3 , H2O, CH4 , N2O, HNO3 , and temperature profiles. The OSIRIS limb spectrometer and the SMR radiometer onboard Swedish satellite Odin will measure O3 , NO, NO2 among others. The Danish Ørsted satellite will provide a particle detector to measure the flux of fast electrons, protons, and alpha particles, thus quantifying the energetic particle precipitation producing odd nitric oxide.
The Sodankylä Geophysical Observatory (SGO) and the Finnish Meteorological Institute (FMI) are developing a detailed chemical model on the base of the Sodankylä Ion Chemistry Model (SIC) in order to utilize these new data sets and study the effects of solar radiation and energetic particles on mesospheric and stratospheric concentrations. The purpose is to model in detail the process chain starting from ionization in the mesosphere to the destruction of ozone in the stratosphere.
We will present our project, the latest development of our model, and preliminary modeling studies on the effects of solar proton events on middle atmospheric NO and ozone.