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| Titel |
The effect of model spatial resolution on Secondary Organic Aerosol predictions |
| VerfasserIn |
C. Wainwright, J. R. Pierce, J. Liggio, K. Strawbridge, A. M. Macdonald, R. Leaitch |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250061124
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| Zusammenfassung |
| Abstract
Between 20-90% of submicron aerosol mass throughout the continental boundary
layer consists of secondary organic aerosol (SOA). As such, the ability of chemical
transport models to accurately reproduce the continental boundary layer aerosol
greatly depends on their ability to predict SOA. Although there has been much
recent effort to better describe SOA formation mechanisms in models, little attention
has been paid to the effects of model spatial resolution on SOA predictions. SOA
predictability should improve with model resolution; however, it is unclear how
finely resolved a model must be to make accurate predictions. The Whistler Aerosol
and Cloud Study (WACS 2010), held between June 22nd and July 28th, 2010 and
conducted at Whistler, BC, Canada provides a unique data set for testing simulated
SOA predictions. The study consisted of intensive measurements of trace particles
and gases in the atmosphere in a mountain valley. We test the ability of the global
chemical transport model GEOS-chem (www.geos-chem.org) to predict the aerosol
concentrations during this event and throughout the campaign. Simulations were performed
using three different resolutions of the model: 4ºx5º (~400 km), 2ºx2.5º (~200
km) and 0.5ºx0.667º (~50 km). The 4ºx5º version of the model significantly under
predicts organic aerosol (max organics ~1.5μg m-3when measurements were ~7μg
m-3), while the 2ºx2.5º and 0.5ºx0.667º versions are much more closely compared
with measurements (max organics ~5μgm-3). In addition to analysis at Whistler,
data from the same simulations was used to perform a comparison across North
America between the 4ºx5º and 0.5ºx0.667º versions of the model. It was found that,
on average, the 0.5ºx0.667º were significantly higher (~2-4 μg m-3) for various
places in North America (near sources and near coastlines), which suggests that
sub-grid variability in temperature and semi-volatile partitioning causes the 4ºx5º
simulations to underpredict SOA concentrations relative to higher resolution simulations. |
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