Naslov
Downscaling of ECMWF ensemble forecasts for cases of severe weather : Ensemble statistics and cluster analysis

Autori
Branković, Čedo ; Matjačić, Blaženka ; Ivatek-Šahdan, Stjepan ; Buizza, Roberto

Izvornik
Monthly weather review (0027-0644) 136 (2008), 9; 3323-3342

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
dynamical downscaling; ensemble forecasts; severe weather; ECMWF; clustering; Aladin

Sažetak
Dynamical downscaling has been applied to global ensemble forecasts to assess its impact for four cases of severe weather (precipitation and wind) over various parts of Croatia. It was performed with the Croatian 12.2-km version of the Aladin limited area model, nested in the ECMWF TL255 (approximately 80 km)global Ensemble Prediction System (EPS). The 3-hourly EPS output was used to force the Aladin model over the central European/northern Mediterranean domain. Results indicate that the identical clustering algorithm may yield differing results when applied to either global or to downscaled ensembles. It is argued that this is linked to the fact that downscaled, higher-resolution ensemble resolves more explicitly small-scale features, in particular those strongly influenced by orographic forcing. This result has important implications in limited-area ensemble prediction, since it implies that downscaling may affect the interpretation or relevance of the global ensemble forecasts, i.e. it may not always be feasible to make a selection (or a subset) of global lower-resolution ensemble members that might be representative of all possible higher-resolution evolution scenarios.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

POVEZANOST RADA