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| Titel |
Lower tropospheric COS as main source of stratospheric background aerosol, a CCM study |
| VerfasserIn |
Christoph Brühl, Holger Tost, Paul Crutzen  , Jos Lelieveld , Francois Benduhn |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250051317
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| Zusammenfassung |
| The modular atmospheric chemistry circulation model EMAC with the aerosol module gmxe
and high vertical resolution has been used for multiyear simulations of atmospheric aerosol.
As lower boundary condition observed concentrations of COS and other longlived source
gases are used, together with emissions of shorter lived gas and aerosol species. The
parameters for the aerosol size distribution in the 7 modes are the same for troposphere and
middle atmosphere. Evaporation of sulfate particles in the middle atmosphere is taken
into account. We show that the oxidation of COS transported into the stratosphere
explains most of the stratospheric background aerosol (Junge layer) and SO2 observed
by satellites (SAGE, Space Shuttle), including the modulation by the (internally
calculated) Quasi-Biennial Oscillation. Tropospheric SO2 has a minimum below the
tropopause due to scavenging and cannot be a large contribution to stratospheric
sulfur.
We show also, that the model is able to build up the aerosol from a volcanic SO2
injection, and discuss some radiation effects. For both, the background, and the volcanic
aerosol, the sedimentation is critical. |
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