Proceedings - C-SRNWP Project

uncertainty in the model physics, they are: Bougeault-type scheme of deep convection,
the modified Kain-Fritsch deep convection scheme, moisture convergence and CAPE
closure in the convection scheme, Kessler-type scheme for large scale precipitation,
Lopez microphysics scheme, tuning of the mixing length, entrainment rate, and the
computation of the cloud base. The results are shown in Fig. 6-7.
Figure 6. 850hPa Temperature spread of the LAEF experiments with and without
multi-physics.
The results demonstrate that the multi-physics option in the LAMEPS brings much
benefit for improving the diversity of the system
2.4 Dynamical downscaling of ECMWF EPS (by Ivatek-Sahdan, Brankovic, Matjacic,
Pistotnik, Szintai, Ihasz, Kertesz)
The computational framework for dynamical downscaling the ECMWF EPS members
with ALADIN at ECMWF has been started to implement. A large part of the work
necessary to establish the facility to run ALADIN – a deterministic run as well as
ensemble runs – on the high performance computing facility at ECMWF has been done.
However, still some additional work is needed until a technically working ALADIN
LAEF system becomes useable and enables the conduction of case studies and
performance tests.
In Crotia, during 2005 and 2006 Studies of the ECMWF EPS downscaling were done.
First clustering of the global model results (ECMWF-EPS), and afterwards, clustering
of EPS forecasts downscaled with ALADIN NWP model. Four cases with Severe
weather (precipitation and wind) in 2003 and 2004 were studied. 5 day forecasts of the
full set of 50+1 ECMWF EPS members were downscaled with ALADIN on old LACE
domain (12.2 km horizontal resolution 37 levels).
Results from both systems were manipulated in the same way (interpolated to
0.5°x0.5° grid) to determine the impact of dynamical downscaling. Comparison with
ECMWF analysis was done on same resolution. Clustering was done using the Metview
SW and a lot of Macros were developed for that purpose. Unfortunately clustering on
the Lambert projection was not possible with Metview.
First results for the chosen severe weather events in Croatia show that downscaling is a
useful tool, especially if topography is the triggering effect and it is promising that good
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