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| Titel |
Scale bridging in atmospheric composition simulation for air quality studies |
| VerfasserIn |
Alberto Maurizi, Felicita Russo, Massimo D'Isidoro, Francesco Tampieri |
| 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 |
250051349
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| Zusammenfassung |
| The processes determining the atmospheric composition and its evolution cover a wide
spectrum of scales, ranging from the global scale ( interesting for climate and large scale
transport episodes like volcanic eruptions or large forest fires) to the molecular
scale ( where dissipation of energy takes place along with the basic transformation
processes).
Moreover, studying the interaction between climate and anthropogenic activities,
specifically those concentrated in megacities/hot spots, require the description of
processes in a very wide range of scales from local (where anthropogenic emissions
are concentrated) to global (where we are interested to study the impact of these
sources).
A complete treatment of these processes implies therefore the ability of connecting their
descriptions at the different scales. This connection is already well established in the direction
of global-to-regional (or regional-to-local) when the output from coarser models is used to
feed boundary conditions into more refined models. This is done routinely, for example, in
meteorological applications.
The exchange of information in the reverse sense (i.e. the feed of information from a high
resolution model to a coarse resolution model) is higly non-trivial. Such kind of interaction is
of high interest expecially for air quality studies. In fact in large scale simulations we expect
the largest uncertainties to correspond to the most polluted areas where the highly
inhomogeneous distribution of sources together with the intrinsic non-linearity of the
processes involved can generate non negligeable departures between coarse and fine scale
simulations.
In the work presented here, the nudging approach has been used to force the low
resolution chemical composition model using an high resolution run. A numerical experiment
simulating the year 2007 is performed to apply the method to the case of the Po Valley hot
spot using BOLCHEM, an atmospheric dynamic and composition model in which
meteorology and chemistry are coupled online. The results show that in general the forced
low resolution model simulation is closer to the high resolution than the non-forced model,
and this variation changes with the species and the season. We also observed an influence
of the forcing outside of the forcing area and the spread of the effect outside the
forcing area is quantified to be at least about 5% over an extension about 9 times
larger. |
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