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| Titel |
Case studies on aerosol feedback for Europe with WRF-Chem |
| VerfasserIn |
Renate Forkel, Johannes Werhahn, Peter Suppan |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250080907
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| Zusammenfassung |
| As the strength of the simulated feedback between aerosol concentrations and meteorological
variables depends on ambient aerosol concentration and the prevailing meteorological
conditions, pollutant sources as well as lateral boundary conditions have a major influence.
Case studies with the online coupled meteorology-chemistry model WRF-Chem were
performed for Europe in order to estimate the possible range of boundary values and
emission impact. Differences from results without feedback can be expected for high
particle concentrations but also for extremely low aerosol particle numbers. For
example, as compared to a simulation where the indirect aerosol effect was not
considered, the inclusion of the indirect aerosol effect resulted in an up to 70% lower
cloud water content and almost a 100% higher mean solar radiation over the North
Atlantic and Northern Europe when standard background boundary conditions for
anthropogenic particulate matter were assumed. The simulated low cloud droplet
concentrations, which are a result of the low aerosol concentrations in this area
are significantly smaller than the 250 droplets cm-3 that are assumed when no
indirect effect is considered. Even for boundary conditions with anthropogenic
particulate matter concentrations that are beyond usual values the cloud droplet
number does not reach the value assumed in the absence of the indirect effect and the
simulated solar radiation in this area was found to be still 50% higher than without the
indirect effect. In contrast to the immediate impact of the indirect and also of the
direct aerosol effect on solar radiation the semi-direct effect and the second indirect
effect develop with time. Semi-direct effects developing with time and subsequent
impact pollutant distributions on were more pronounced over continental Europe.
Further case studies on the effect of boundary values and emissions will be discussed. |
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