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Nat. Hazards Earth Syst. Sci., 8, 19-35, 2008
www.nat-hazards-earth-syst-sci.net/8/19/2008/
doi:10.5194/nhess-8-19-2008
© Author(s) 2008. This work is licensed
under a Creative Commons License.


Numerical analysis of an intense rainstorm occurred in southern Italy

S. Federico1,2, E. Avolio2,3, C. Bellecci2,3, A. Lavagnini4, M. Colacino4, and R. L. Walko5
1CNR-ISAC, Strada Prov. Lecce-Monteroni km 1.2, Lecce, Italy
2CRATI Scrl, c/o Università della Calabria, Rende (CS), Italy
3Facoltà di Ingegneria-Università di "Tor Vergata", via del Politecnico 1, Rome, Italy
4CNR-ISAC, Via del Fosso del Cavaliere 100, Rome, Italy
5Pratt School, Duke University, Durham, NC, USA

Abstract. In this study we conduct a numerical analysis of an intense and destructive storm that occurred over Calabria, southern Italy, on 10–12 December 2003. More than 250 mm of precipitation was recorded over a large area in southern Calabria and one station reported about 660 mm in two days (more than half of the yearly climatological value). Precipitation fell mainly during 11 and 12 December. The storm was characterized by the entrance of an Atlantic upper-level trough associated with a deep surface low that advected humid marine air toward steep Calabrian orography. The steep mountain ridges favoured landslides, which were reported in several villages. Property damage was extensive.

We study the storm at the mesoscale by means of the Regional Atmospheric Modeling System (RAMS). The model was successful at representing the observed accumulated rainfall patterns. This justifies our use of RAMS for further analysis of the physical and dynamic factors involved in the storm event. In particular, we use RAMS to evaluate the roles of Calabrian orography, surface latent heat flux, and upper level forcing.

The key role of a potential vorticity (PV) streamer, which forced the entire meteorological system from the upper levels is assessed by the PV inversion technique in a Limited Area Model Ensemble Prediction System (LEPS) framework.

Results show that the roles of Calabrian orography and surface latent heat flux are important in our simulations. Indeed, humid marine air masses were advected by the synoptic flow toward Calabrian steep coastal mountain ranges determining intense and abundant rainfall.


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Citation: Federico, S., Avolio, E., Bellecci, C., Lavagnini, A., Colacino, M., and Walko, R. L.: Numerical analysis of an intense rainstorm occurred in southern Italy, Nat. Hazards Earth Syst. Sci., 8, 19-35, doi:10.5194/nhess-8-19-2008, 2008.   Bibtex   EndNote   Reference Manager    XML
 

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