Oulun yliopisto

Sodankylä Ion Chemistry

The Sodankylä Ion-Neutral Chemistry (SIC) model is a comprehensive 1-dimensional coupled model of the chemistry of the middle atmosphere, i.e. the mesosphere and lower thermosphere as well as the ionospheric D region. SIC has been developed by the SGO Aeronomy Group under the lead of Dr Esa Turunen in close collaboration with the Earth Observation Group of the Finnish Meteorological Institute.

SIC includes more than 400 reactions of

Sources of ionisation accounted for are solar UV, X rays, protons and electrons, as well as galactic cosmic rays.

SIC can be run either in a steady-state mode, which calculates the equilibrium concentrations of the modelled components, or in a time-dependent mode where the concentrations are advanced in time using the modified Euler method for stiff equations. The steady-state mode is suitable for estimating the effects of constant forcing during daytime, whereas the time-dependent mode allows us to study effects of diurnal variations or transient events, such as precipitation of energetic particles.

The SIC Model is used extensively in our international research network CHAMOS (Chemical Aeronomy of the Mesosphere and Ozone in the Stratosphere). All members of the SIC model team are also members of the larger CHAMOS Network.

Members of the SIC model team currently include:

  • Dr Esa Turunen, EISCAT Scientific Association, team leader;
  • Dr Thomas Ulich, Dr Carl-Fredrik Enell and Dr. Antti Kero, SGO; and
  • Dr Pekka Verronen and Dr Annika Seppälä at FMI/Earth Observation.

Further descriptions of SIC and its development from the original steady-state ion chemistry model into the present time-dependent coupled ion-neutral model can be found in the refereed scientific literature, which also contain updated lists of the reaction rate coefficients used.

Last modified: 02 June 2010, 04:52:43.