References

NHESS

Natural Hazards and Earth System Sciences

NHESS

Nat. Hazards Earth Syst. Sci.

1684-9981

Copernicus Publications

Göttingen, Germany

10.5194/nhess-8-19-2008

Numerical analysis of an intense rainstorm occurred in southern Italy

Federico

¹ ² Avolio

² ³ Bellecci

² ³ Lavagnini

⁴ Colacino

⁴ Walko

R. L.

⁵

CNR-ISAC, Strada Prov. Lecce-Monteroni km 1.2, Lecce, Italy

CRATI Scrl, c/o Università della Calabria, Rende (CS), Italy

Facoltà di Ingegneria-Università di "Tor Vergata", via del Politecnico 1, Rome, Italy

CNR-ISAC, Via del Fosso del Cavaliere 100, Rome, Italy

Pratt School, Duke University, Durham, NC, USA

11 01 2008

8 1 19 35

2008

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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.

References 1

Alpert, P., Ben-gai, T., Baharad, A., Benjamini, D., Yekutieli, D., Colacino, M., Diodato, L., Ramis, V., Romero, R., Michaelides, S., and Manes, A.: The paradoxial increase of Mediterranean extreme daily rainfall in spite of decrease in total values, Geophys. Res. Lett., 29(11), 1536, https://doi.org/10.1029/2001GL013554, 2002.

Atlas, R. and Reale, O.: Tropical cyclone-like vortices in the extratropics: Observational evidence and synoptic analysis, Wea. Forecasting, 16, 7–34, 2001.

Baldwin, M. E.: QPF verification system documentation, http://www.emc.ncep.noaa.gov/mmb/ylin/pcpverif/scores/docs/mbdoc/pptmethod.html, last access: 9~January~2008, 2000.

Buzzi, A. and Tibaldi, S.: Cyclogenesis on the lee of the Alps: A case study, Q. J. Roy. Meteor. Soc., 104, 271–287, 1978.

Buzzi A. and Foschini, L.: Mesoscale meteorological features associated with heavy precipitation in the southern Alpine region, Meteor. Atmos. Phys, 72, 131–146, 2000.

Charney, J. G.: The use of primitive equations of motions in numerical prediction, Tellus, 7, 22–26, 1955.

Cotton, W. R., Pielke, R. A. Sr., Walko, R. L., Liston, G. E., Tremback, C. J., Jiang, H., McAnelly, R. L., Harrington, J. Y., Nicholls, M. E., Carrio, G. G., and McFadden, J. P.: RAMS 2001: Current satus and future directions, Meteor. Atm., 82, 5–29, 2003.

Davis, C. A., and Emmanuel, K. A.: Potential vorticity diagnosis of cyclogenesis, Mon. Wea. Rev., 119, 1397–1411, 1991.

Federico, S., Bellecci, C., and Colacino, M.: Quantitative precipitation of the Soverato flood: The role of orography and surface fluxes, Nuov. Cim. C., 26~C, 7–22, 2003a.

Federico, S., Bellecci, C., and Colacino, M.: Numerical simulation of Crotone flood: storm evolution, Nuov. Cim. C., 26~C, 357–371, 2003b.

Federico, S., Avolio, E., Bellecci, C., Colacino, M., and Walko, R. L.: Application of the LEPS technique for Quantitative Precipitation Forecasting (QPF) in southern Italy: A preliminary study, Nonlin. Processes Geophys., 13, 53–66, 2006.

Federico, S., Avolio, E., Bellecci, C., Lavagnini, A., and Walko, R. L.: Predictability of intense rain storms in the Central Mediterranean basin: sensitivity to upper-level forcing, Adv. Geosci., 12, 5–18, 2007.

Fehlmann, R. and Davies, H. C.: Role of salient potential vorticity elements in an event of frontal-wave cyclogenesis, Q. J. Roy. Meteor. Soc., 125, 1801–1824, 1999.

Fehlmann, R., Quadri, C., and Davies, H. C.: An Alpine rainstorm: Sensitivity to the mesoscale upper level structure, Wea. Forecasting, 15, 4–28, 2000.

Haltiner, G. J. and Williams, R. T.: Numerical prediction and dynamic meteorology, 2nd Edition, Johm Wiley & Sons, New York, 1980.

Homar, V., Ramis, C., and Alonso, S.: A deep cyclone of African origin over the Western Mediterranean: diagnosis and numerical simulation, Ann. Geophys., 20, 93–106, 2001.

Homar, V., Romero R., Ramis, C., and Alonso, S.: Numerical study of the October~2000 torrential precipitation over eastern Spain: analysis of the synoptic-scale stationarity, Ann. Geophys., 20, 2047–2066, 2002.

Hoskins, B. J., McIntyre, M. E., and Robertson, A. W.: On the use and significance of isentropic potential vorticity maps, Q. J. Roy. Meteor. Soc., 111, 877–946, 1985.

Jansa, A., Radinovic, D., Alpert, P., Genoves, A., Campins, J., and Picornell, M. A.: Mediterranean cyclones: Subject of a WMO Project, Internat. Symposium on the Life Cycle of Extratropical Cyclones, Bergen, Vol II, 26–31, 1994.

Krichak, S. O., Alpert, P., and Melina, D.: The role of atmospheric processes associated with hurricane Olga in the December~2001 floods in Israel, J. Hydrometeor., 5, 1259–1270, 2004.

Krichak, S. O., Alpert, P., and Dayan, M.: A southeastern Mediterranean PV streamer and its role in December~2001 case with torrential rains in Israel, Nat. Hazards Earth Syst. Sci., 7, 1–12, 2007.

Martin, A., Romero, R., Homar, V., De Luque, A., Alonso, S., Rigo, T., and Llasat, C.: Sensitivities of a flash flood event over Catalonia: a numerial analysis, Mon. Wea. Rev., 135, 651–669, 2007.

Mass, C. F., Ovens, D., Westrick, K., and Colle, B. A.: Does increasing horizontal resolution produce more skilful forecasts?, B. Am. Meteorol. Soc., 83, 407–430, 2002.

Molinari, J. and Corsetti, T.: Incorporation of cloud-scale and mesoscale down-drafts into a cumulus parametrization: results of one and three-dimensional integrations, Mon. Wea. Rev., 113, 485–501, 1985.

Pastor, F., Estrela, M. J., Peñarrocha, D., and Millán, M. M.: Torrential Rains on the Spanish Mediterranean Coast: Modeling the Effects of the Sea Surface Temperature, J. Appl. Met., 40, 1180–1195, 2001.

Pielke, R. A., Cotton, W. R., Walko, R. L., Tremback, C. J., Lyons, W. A., Grasso, L. D., Nicholls, M. E., Murran, M. D., Wesley, D. A., Lee, T. H., and Copeland, J. H.: A comprehensive meteorological modelling system-RAMS, Meteorol. Atmos. Phys., 49, 69–91, 1992.

Romero, R., Ramis, C., Alonso, S., Doswell III, C. A., and Stensrud, D. J.: Mesoscale Model Simulations of Three Heavy Precipitation Events in the Western Mediterranean Region, Mon. Wea. Rev., 126, 1859–1881, 1998.

Romero, R., Martín, A. , Homar, V., Alonso, S., and Ramis, C.: Predictability of prototype flash flood events in the Western Mediterranean under uncertainties of the precursor upper-level disturbance: The HYDROPTIMET case study, Nat. Hazards Earth Syst. Sci., 5, 505–525, 2005.

Santurette, P. and Georgiev, C. G.: Weather Analysis and Forecasting, Elsevier Academic Press, 179~pp., 2005.

Siccardi, F.: Rainstorm hazards and related disasters in the western Mediterranean region, Remote Sens. Rev., 14, 5–21, 1996.

Stein, U. and Alpert, P.: Factor Separation in Numerical Simulations, J. Atmos. Sci., 50, 2107–2115, 1993.

Turato, B., Reale, O. and Siccardi, F.: Water Vapor Sources of the October~2000 Piedmont Flood, J. Hydrometeor., 5, 693–712, 2004.

Walko, R. L., Band, L. E., Baron, J., Kittel, T. G., Lammers, R., Lee, T. J., Ojima, D., Pielke, R. A. Sr., Taylor, C., Tague, C., Tremback, C. J., and Vidale, P. L.: Coupled Atmosphere-Biosphere-Hydrology Models for environmental prediction, J. Appl. Met., 39, 931–944, 2000.