Regional and intercontinental modelling - Air Pollution Modeling and Its Application - page 195

126 geo-referenced tree species over the most part of Europe. Chemistry transport
models also allow to trace-back the origin of simulated secondary species by
analysing the chemical production terms individually for relevant precursors. This
has been done choosing a control volume for which simulated production terms
have been examined.
2. Methods
The biogenic emissions have been estimated following the methods proposed by
Simpson et al. (1999). The original land use dataset is based on CORINE-land-
use-data - modified by Smiatek (1998). Only three forest classes were available:
deciduous, coniferous and mixed forest. Emissions were estimated based on the bio-
mass associated to six statistically distributed surrogate tree-species. A second land-
use database has been constructed implementing information about tree-species
from Köble et al. (2001) in the original land-use-database. They developed a tree
species map mainly combining the site inventory information on 126 tree species
from ICP Forests, CORINE land cover, satellite and statistical data for the EU.
The Chemistry Transport Model REM_Calgrid (RCG) (Beekmann et al., 2007 and
references therein) has been used for simulating O 3 and PM10. Secondary aerosols
are divided into fine inorganic and organic aerosols. Organic particles are subdivided
into aerosols stemming from biogenic and anthropogenic precursors. Production
of secondary organic aerosol (SOA) from anthropogenic and biogenic VOC is
treated with the SORGAM module. Simulations started on 20 July 2005 at 00:00
UTC and ended on 30 July 2005 at 00:00 UTC. Meteorological data were
calculated based on observations. Anthropogenic emissions were based on EMEP
information and spatially disaggregated by TNO.
3. Results and Discussion
The biggest differences in the biogenic precursor emissions were found in
Scandinavia and over the North-Western Russian Area, in Spain and over the Alps.
RCG was not able to capture ozone maxima over Spain. RCG-simulation with
biogenic emissions derived from detailed tree information improved considerably.
Especially in Spain, Italy and also between the Netherlands and the Ruhr-Area in
Germany, up to 15% higher ozone values are modeled, when biogenic emissions
were based on the detailed forest data-base.
Figure 1 shows the absolute values of the secondary organic aerosols simulated
with RCG for the considered time-period. Biogenic emission estimates were based
on land-use data without ( Fig. 1a) and with (Fig. 1b) detailed tree information.
While both integrations show spatially highest secondary organic aerosols over