 |
| Titel |
Coupling FLEXPART to the regional scale numerical weather prediction model COSMO: Implementation, evaluation and first results |
| VerfasserIn |
Stephan Henne, Pirmin Kaufmann, Martin Schraner, Dominik Brunner |
| Konferenz |
EGU General Assembly 2013
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250082935
|
|
|
|
|
|
| Zusammenfassung |
| The Lagrangian particle dispersion model FLEXPART is a well-known and robust research
tool used by many atmospheric scientists worldwide. In its standard version FLEXPART was
developed for the use with global or limited area input files from the European
Centre for Medium Range Weather Forecast (ECMWF). Further versions exist for
input from the NCEP (National Centers for Environmental Prediction) GFS (Global
Forecasting System) model and for regional scale input from the MM5 model and its
successor WRF. In Europe several national weather services and research groups
develop and operate the non-hydrostatic limited-area atmospheric model COSMO
(Consortium for Small-scale Modeling). At MeteoSwiss COSMO is operationally run
with data assimilation on two grids with approximately 7 km x 7 km and 2 km x 2
km horizontal resolution centered over Switzerland This offers the exceptional
opportunity of studying atmospheric transport over complex terrain on an long-term
basis.
To this end, we have developed a new version of FLEXPART that is offline coupled to
COSMO output (FLEXPART-COSMO hereafter) and supports output from multiple COSMO
nests. The version features several new developments as compared to the standard
version. Most importantly, particles are internally referenced against the native
vertical coordinate system used in COSMO and not, as in standard FLEXPART, in a
terrain following z-system. This eliminates the need for an additional interpolation
step. A new flux deaccumulation scheme was introduced that removes the need for
additional preprocessing of the input files. In addition to the existing Emmanuel
based convection parameterisation, a convection parameterisation based on the
Tiedtke scheme, which is identical to the one implemented in COSMO itself, was
introduced. A possibility for offline nesting of a FLEXPART-COSMO run into a
FLEXPART-ECMWF run for backward simulations was developed that only requires minor
modifications on the FLEXPART-ECMWF version and allows particles to leave the limited
COSMO domain. On the technical side, we added an OpenMP shared-memory
parallelisation to the model, which also allows for asynchronous reading of input
data.
Here we present results from several model performance tests under different
conditions and compare these with results from standard FLEXPART simulations using
nested ECMWF input. This analysis will contain evaluation of deposition fields,
comparison of convection schemes and performance analysis of the parallel version.
Furthermore, a series of forward-backward simulations were conducted in order
to test the robustness of model results independent of the integration direction.
Finally, selected examples from recent applications of the model to transport of
radioactive and conservative tracers and for in-situ measurement characterisation will be
presented. |
|
|
|
|
|
|