Chapter 50
Evaluation of the New Version
of Stratospheric Chemistry Module
of the SILAM CTM
Risto Hänninen, Mikhail Sofiev, Rostislav Kouznetsov and Viktoria Sofieva
Abstract The effect of different bromine and chlorine species on ozone is here
evaluated using a System for Integrated modeLling of Atmospheric coMposition,
SILAM. The new stratospheric chemistry module includes 15 chlorine and 9 bromine
species together with their gas-phase and heterogeneous reactions with other species.
Evaluation of ozone concentrations is obtained by using the steady-state, which is
obtained after spin-up time of several decades. The amount of halogens is estimated
by including bromine emissions from sea (e.g. sea-salt), from biomass burning and
from terrestrial sources. For chlorine we used the emissions from the GEIA inventory,
with additional yearly scaling of the different CFC emissions.
50.1 Introduction
It is well-known that the amount of ozone is affected by halogens. Especially the
heterogeneous reactions in polar stratospheric clouds (PSC) are expected to be the
main cause for the ozone depletion in polar regions: the reactions in PSC convert
bromine and chlorine species to their active form which eventually react with ozone.
The concentrations of different gases in stratosphere also affect their concentrations
in troposphere. Therefore, a better model for stratospheric chemistry reactions will
also improve the modelling of, e.g. ozone, NO 2 , and NO 3 in the lower troposphere
where these different species may have important health effects.
R. Hänninen (B) · M. Sofiev · R. Kouznetsov · V. Sofieva
Finnish Meteorological Institute, Helsinki, Finland
e-mail: Risto.Hanninen@fmi.fi
M. Sofiev
e-mail: Mikhail.Sofiev@fmi.fi
R. Kouznetsov
e-mail: Rostislav.Kouznetsov@fmi.fi
V. Sofieva
e-mail: Viktoria.Sofieva@fmi.fi
© Springer Nature Switzerland AG 2020
C. Mensink et al. (eds.), Air Pollution Modeling and its Application XXVI,
Springer Proceedings in Complexity,
https://doi.org/10.1007/978-3-030-22055-6_50
317
Evaluation of the New Version
of Stratospheric Chemistry Module
of the SILAM CTM
Risto Hänninen, Mikhail Sofiev, Rostislav Kouznetsov and Viktoria Sofieva
Abstract The effect of different bromine and chlorine species on ozone is here
evaluated using a System for Integrated modeLling of Atmospheric coMposition,
SILAM. The new stratospheric chemistry module includes 15 chlorine and 9 bromine
species together with their gas-phase and heterogeneous reactions with other species.
Evaluation of ozone concentrations is obtained by using the steady-state, which is
obtained after spin-up time of several decades. The amount of halogens is estimated
by including bromine emissions from sea (e.g. sea-salt), from biomass burning and
from terrestrial sources. For chlorine we used the emissions from the GEIA inventory,
with additional yearly scaling of the different CFC emissions.
50.1 Introduction
It is well-known that the amount of ozone is affected by halogens. Especially the
heterogeneous reactions in polar stratospheric clouds (PSC) are expected to be the
main cause for the ozone depletion in polar regions: the reactions in PSC convert
bromine and chlorine species to their active form which eventually react with ozone.
The concentrations of different gases in stratosphere also affect their concentrations
in troposphere. Therefore, a better model for stratospheric chemistry reactions will
also improve the modelling of, e.g. ozone, NO 2 , and NO 3 in the lower troposphere
where these different species may have important health effects.
R. Hänninen (B) · M. Sofiev · R. Kouznetsov · V. Sofieva
Finnish Meteorological Institute, Helsinki, Finland
e-mail: Risto.Hanninen@fmi.fi
M. Sofiev
e-mail: Mikhail.Sofiev@fmi.fi
R. Kouznetsov
e-mail: Rostislav.Kouznetsov@fmi.fi
V. Sofieva
e-mail: Viktoria.Sofieva@fmi.fi
© Springer Nature Switzerland AG 2020
C. Mensink et al. (eds.), Air Pollution Modeling and its Application XXVI,
Springer Proceedings in Complexity,
https://doi.org/10.1007/978-3-030-22055-6_50
317