Environmental Engineering Reference
In-Depth Information
data of GME. The runs are performed with the uniform COSMO resolutions of
approximately 16 km (N1: Europe), 8 km (N2: Germany) and 2.8 km (N3:
Saxony). In all domains MUSCAT uses block-structured grids with three different
horizontal resolutions. For instance, the innermost region of interest covers an area
of 240 × 156 km (Saxony) with variable resolution between 2.8 and 0.7 km, where
the finest grid was arranged around the city of Dresden. The simulation was
performed for 1 week in October 2006.
The tests for the advection problems confirm that the modified version of
MUSCAT, implementing our improved multirate IMEX scheme, calculates results
that are comparable to the results of the singlerate version. Small differences were
only observable near to the boundaries between blocks with different time levels.
The coupling between aerosol dynamics and gas phase chemistry using the multirate
IMEX approach works well for the real scenario and allows larger coupling time
steps. The computational costs can be reduced significantly in all three domains.
The study show the potential of multirate IMEX schemes to reduce calculation
cost. An additional effect is the reduced communication between different partitions.
Acknowledgments
The work was supported by the DFG, the ZIH Dresden and the NIC Jülich.
Furthermore, we thank the DWD Offenbach for good cooperation.
References
Constantinescu EM, Sandu A (2007) Mu
ltirate timestepping methods for hyperbolic conservation
laws. J. Sci. Comput. 33:239-278
Hinneburg D, Renner E, Wolke R (2009) F
ormation of secondary inorganic aerosols by power
plant emissions exhausted through cooling towers in Saxony. Env. Sci. Pollut Res. 16:25-35
Knoth O, Wolke R (1998) An ex
plicit-implicit numerical approach for atmospheric chemistry-
transport modeling. Atmos. Env. 32:1785-1797
Osher S, Sanders R (1983)
Numerical approximations to nonlinear conservation laws with
locally varying time and space grids. Math. Comput. 41:321-336
Schlegel M, Knoth O, Arnold M, Wolke R (2009).
Multirate Runge-Kutta schemes for advection
equarions. J. Comput. Appl. Math. 226:345-357
Vignati E., Wilson J, Stier P (2004) M7
: An efficient size-resolved aerosol microphysics module
for large-scale aerosol transport models. J. Geophys. Res. 109, D22202, doi: 10.1029/2003
JD004485.
transport modeling system LM-MUSCAT: Description and CityDelta applications. In:Air
Pollution Modeling and its Applicaton XVI, 427-439. Kluwer Academic/Plenum Publisher
Wolke R, Knoth O (2000) Impl
icit-explicit Runge-Kutta methods applied to atmospheric
chemistry-transport modelling. Environmental Modelling and Software, 15:711-719
