@article {4943,
	title = {Numerical modeling and analysis of the effect of complex Greek topography on tornadogenesis},
	journal = {Natural Hazards and Earth System Sciences},
	volume = {14},
	year = {2014},
	note = {Export Date: 2 November 2015Correspondence Address: Matsangouras, I.T.; Laboratory of Climatology and Atmospheric Environment, Faculty of Geology and Geoenvironment, University of Athens, Panepistimioupolis, 15784, Athens, Greece; email: john_matsa@geol.uoa.grReferences: Basiakos, I., Katsaras, P., Alexiou, I., Mavroudis, A., Karanikas, T., Skrimizeas, P., Operational workstations at the hellenic national meteorological service \& a windows nt based briefing system (2000) 11th European Working Group on Operational Meteorological Workstations (11th EGOWS), , 5-8 June 2000, Helsinki, Finland;Beck, A., Ahrens, B., Stadlbacher, K., Impact of nesting strategies in dynamical downscaling of reanalysis data (2004) Geophys. Res. Lett., 31, pp. L19101. , doi:10.1029/2004GL020115; 
Bosart, L.F., Seimon, A., Lapenta, K.D., Dickinson, M.J., Su-percell tornadogenesis over complex terrain: The Great Barring-ton, Massachusetts, tornado on 29 May 1995 (2006) Weather Forecast., 21, pp. 897-922; 
Braun, S.A., Monteverdi, J.P., An analysis of a mesocyclone-induced tornado occurrence in Northern California (1991) Weather Forecast., 6, pp. 13-31; 
Brooks, H.E., Proximity soundings for severe convection for Europe and the United States from reanalysis data (2009) Atmos. Res., 93, pp. 546-553; 
Brooks, H.E., Doswell Iii., C.A., Kay, M.P., Climatological estimates of local daily tornado probability for the United States (2003) Weather Forecast., 18, pp. 626-640; 
Chen, C.-S., Lin, Y.-L., Peng, W.-C., Liu, C.-L., Investigation of a heavy rainfallevent over southwestern Taiwan associated with a subsynoptic cyclone during the 2003 Mei-Yu season (2010) Atmos. Res., 95, pp. 235-254; 
Chen, C.-S., Lin, Y.-L., Hsu, N.-N., Liu, C.-L., Chen, C.-Y., Orographic effects on localized heavy rainfall events over southwestern Taiwan on 27 and 28 June 2008 during the post-Mei-Yu period (2011) Atmos. Res., 101, pp. 595-610; 
Chen, C.-S., Lin, Y.-L., Zeng, H.-T., Chen, C.-Y., Liu, C.-L., Orographic effects on heavy rainfall events over northeastern Taiwan during the northeasterly monsoon season (2013) Atmos. Res., 122, pp. 310-335; 
Chen, F., Dudhia, J., Coupling an advanced land-surface/hydrology model with the Penn State/NCAR MM5 modeling system. Part I: Model description and implementation (2001) Mon. Weather Rev., 129, pp. 569-585; 
Chiao, S., Lin, Y.-L., Kaplan, M.L., Numerical study of the orographic forcing of heavy precipitation during MAP IOP-2B (2004) Mon. Weather Rev., 132, pp. 2184-2203; 
Colle, B.A., Mass, C.F., Windstorms along the western side of the Washington Cascade Mountains. Part I: A high-resolution observational and modeling study of the 12 February 1995 event (1998) Mon. Weather Rev., 126, pp. 28-52; 
Colle, B.A., Mass, C.F., High-resolution observations and numerical simulations of easterly gap flow through the Strait of Juan de Fuca on 9-10 December 1995 (2000) Mon. Weather Rev., 128, pp. 2398-2422; 
Colle, B.A., Mass, C.F., The 5-9 February 1996 flooding event over the Pacific Northwest: Sensitivity studies and evaluation of the MM5 precipitation forecasts (2000) Mon. Weather Rev., 128, pp. 593-617; 
Craven, J.P., Brooks, H.E., Baseline climatology of sounding derived parameters associated with deep, moist convection, Preprints (2002) 21st Conference on Severe Local Storms, , 12-16 August 2002, St. Antonio, TX, USA; 
Dee, D.P., Uppala, S.M., Simmons, A.J., Berrisford, P., Poli, P., Kobayashi, S., Andrae, U., Vitart, F., The ERA-Interim reanalysis: Configuration and performance of the data assimilation system (2011) Q. J. Roy. Meteor. Soc., 137, pp. 553-597. , doi:10.1002/qj.828; 
Dessens, J., (1984) Les Trombes en France Climatologie et Caract{\'e}ris-tiques Physiques Lannemezan France, , in French); 
Dessens, J., Snow, J.T., (1987) Tornadoes in France Weather Forecast., 4, pp. 110-132; 
Doswell Iii., C.A., The distinction between large-scale and mesoscale contribution to severe convection: A case study example (1987) Weather Forecast., 2, pp. 3-16; 
Doswell Iii., C.A., Evans, J.S., Proximity sounding analysis for derechos and supercells: An assessment of similarities and differences (2003) Atmos. Res., 67-68, pp. 117-133; 
Doswell Iii., C.A., Schultz, D.M., On the use of indices and parameters in forecasting severe storms (2006) E-Journal of Severe Storms Meteorology, 1, pp. 1-22; 
Doswell III, C.A., Brooks, H.E., Maddox, R.A., Flash flood forecasting: An ingredients-based methodology (1996) Weather Forecast., 11, pp. 560-580; 
Droegemeier, K.K., Lazarus, S.M., Davies-Jones, R.D., The influence of helicity on numerically simulated convective storms (2005) Mon. Weather Rev., 121, p. 1993; 
Ebert, E.E., Fuzzy verification of high-resolution gridded forecasts: A review and proposed framework (2008) Meteorol. Appl., 15, pp. 51-64; 
Ferrier, B.S., Lin, Y., Black, T., Rogers, E., Dimego, G., Implementation of a new grid-scale cloud and precipitation scheme in the NCEP Eta model (2002) 15th Conference on Numerical Weather Prediction, pp. 280-283. , Preprints, San Antonio, TX, American Meteorological Society; 
Galanis, G., Louka, P., Katsafados, P., Pytharoulis, I., Kallos, G., Applications of Kalman filters based on non-linear functions to numerical weather predictions (2006) Ann. Geophys., 24, pp. 2451-2460. , doi:10.5194/angeo-24-2451-2006; 
Gay{\`a}, M., Llasat, M.-C., Ar{\'u}s, J., Tornadoes and waterspouts in Catalonia (1950-2009) (2011) Nat. Hazards Earth Syst. Sci., 11, pp. 1875-1883. , doi:10.5194/nhess-11-1875-2011; 
Giaiotti, D.B., Giovannoni, M., Pucillo, A., Stel, F., The climatology of tornadoes and waterspouts in Italy (2007) Atmos. Res., 83, pp. 534-541; 
Gianfreda, F., Miglietta, M.M., Sans{\`o}, P., Tornadoes in Southern Apulia (Italy) (2005) Nat Hazards, 34, pp. 71-89; 
Glickman, T.S., (2000) Glossary of Meteorology, 2nd Edn, p. 855. , American Meteorological Society; 
Gofa, F., Pytharoulis, I., Andreadis, T., Papageorgiou, I., Fragkouli, P., Louka, P., Avgoustoglou, E., Tyrlis, V., Evaluation of the operational NWP forecasts of the Hellenic National Meteorological Service (2008) 9th Conference on Meteorology, Climatology and Atmospheric Physics, pp. 51-58. , 28-31 May, Thessaloniki; 
Groenemeijer, P., Van Delden, A., Sounding-derived parameters in the vicinity of large hail and tornadoes in the Netherlands (2007) Atmos. Res., 67-68, pp. 273-299; 
Groenemeijer, P., Corsmeier, U., Kottmeier, Ch., The development of tornadic storms on the cold side of a front favoured by local enhancement of moisture and CAPE (2011) Atmos. Res., 100, pp. 765-781; 
Hannesen, R., Dotzek, N., Gysi, H., Beheng, K.D., Case study of a tornado in the Upper Rhine valley (1998) Meteorol. Z., 7, pp. 163-170; 
Hart, J.A., Korotky, W., (1991) The SHARP Workstation v1.50 Users Guide, p. 30. , National Weather Service, NOAA U.S. Department of Commerce; 
Homar, V., Gaya, M., Romero, R., Ramis, C., Alonso, S., Tornadoes over complex terrain: An analysis of the 28th August 1999 tornadic event in Eastern Spain (2003) Atmos. Res., 67-68, pp. 301-317; 
Houze Jr., R.A., (1993) Cloud Dynamics, , Academic Press Inc, San Diego, California; 
Iacono, M.J., Delamere, J.S., Mlawer, E.J., Shephard, M.W., Clough, S.A., Collins, W.D., Radiative forcing by long-lived greenhouse gases: Calculations with the AER radiative transfer models (2008) J. Geophys. Res., 113, pp. D13103. , doi:10.1029/2008JD009944; 
Janjic, Z.I., The surface layer in the NCEP Eta Model (1996) Eleventh Conference on Numerical Weather Prediction, pp. 354-355. , 19-23 August, American Meteorological Society, Norfolk, VA; 
Janjic, Z.I., (2002) Nonsingular Implementation of the Mellor-Yamada Level 2.5 Scheme in the NCEP Meso Model, 437, p. 61. , NCEP Office Note; 
Johns, R.H., Doswell Iii., C.A., Severe local storms forecasting (1992) Weather Forecast., 7, pp. 588-612; 
Johns, R.H., Davies, M., Leftwich, P.M., Some wind and instability parameters associated with strong and violent tornadoes. Part II: Variations in the combinations of wind and instability parameters. The Tornado: Its Structure, Dynamics, Hazards, and Prediction (1993) Amer. Geophys. Union, Geophys. Monogr., 79, pp. 583-590; 
Kain, J.S., The Kain-Fritsch convective parameterization: An update (2004) J. Appl. Meteorol., 43, pp. 170-181; 
Katsafados, P., Mavromatidis, E., Papadopoulos, A., Pytharoulis, I., Numerical simulation of a deep Mediterranean storm and its sensitivity on sea surface temperature (2011) Nat. Hazards Earth Syst. Sci., 11, pp. 1233-1246. , doi:10.5194/nhess-11-1233-2011; 
Koletsis, I., Lagouvardos, K., Kotroni, V., Bartzokas, A., Numerical study of a downslope windstorm in Northwestern Greece (2009) Atmos. Res., 94, pp. 178-193; 
Koletsis, I., Lagouvardos, K., Kotroni, V., Bartzokas, A., The interaction of northern wind flow with the complex topography of Crete Island-Part 2: Numerical study (2010) Nat. Hazards Earth Syst. Sci., 10, pp. 1115-1127. , doi:10.5194/nhess-10-1115-2010; 
Liu, J., Bray, M., Han, D., Sensitivity of the Weather Research and Forecasting (WRF) model to downscaling ratios and storm types in rainfall simulation (2012) Hydrol. Process., 26, pp. 3012-3031. , doi:10.1002/hyp.8247; 
Louka, P., Galanis, G., Siebert, N., Kariniotakis, G., Katsafa-Dos, P., Pytharoulis, I., Kallos, G., Improvements in wind speed forecasts for wind power prediction purposes using Kalman filtering (2008) J. Wind Eng. Ind. Aerod., 96, pp. 2348-2362. , doi:10.1016/j.jweia.2008.03.13; 
Markowski, P.M., Straka, J.M., Rasmussen, E.N., Blanchard, E.N., Variability of storm-relative helicity during VORTEX (1998) Mon. Weather Rev., 126, pp. 2959-2971; 
Mass, C., Ovens, D., Westrick, K., Colle, B., Does increasing horizontal resolution produce more skilful forecasts? (2002) B. Am. Meteorol. Soc., 83, pp. 407-430; 
Matsangouras, J.T., Nastos, P.T., The 27 July 2002 tornado event in Athens, Greece (2010) Adv. Sci. Res., 4, pp. 9-13. , doi:10.5194/asr-4-9-2010; 
Matsangouras, I.T., Nastos, P.T., Nikolakis, D., Study of meteorological conditions related to the tornado activity on 25-3-2009 over NW Peloponnesus Greece (2010) Proc. 10th International Conference on Meteorology, Climatology and Atmospheric Physics (COMECAP2010), pp. 417-425. , 25-38 May 2010, Patras, Greece, (in Greek); 
Matsangouras, I.T., Nastos, P.T., Pytharoulis, I., Synoptic-mesoscale analysis and numerical modeling of a tornado event on 12 February 2010 in northern Greece (2011) Adv. Sci. Res., 6, pp. 187-194. , doi:10.5194/asr-6-187-2011; 
Matsangouras, I.T., Nastos, P.T., Sioutas, M.V., 300 Years historical records of tornadoes, waterspouts and funnel clouds over Greece (2011) 6th European Conference on Severe Storms (ECSS 2011), , Palma de Mallorca Balearic Islands, Spain, 3-7 October 2011, ECSS2011-215; 
Matsangouras, I.T., Nastos, P.T., Pytharoulis, I., Numerical investigation of the role of topography in tornado events in greece (2012) Advances in Meteorology, Climatology and Atmospheric Physics, pp. 209-215. , edited by: Helmis C. G. and Nastos, P. T, Springer Berlin Heidelberg, doi:10.1007/978-3-642-29172-2-30; 
Matsangouras, I.T., Nastos, P.T., Bluestein, H.B., Sioutas, M.V., A climatology of tornadic activity over Greece based on historical records (2014) Int. J. Climatol., 34, pp. 2538-2555. , doi:10.1002/joc.3857; 
Meaden, G., Tornadoes in Britain: Their intensities and distribution in space and time (1976) J. Meteorol., 1, pp. 242-251; 
Mellor, G.L., Yamada, T., Development of a turbulence closure model for geophysical fluid problems (1982) Rev. Geophys., 20, pp. 851-875. , doi:10.1029/RG020i004p00851; 
Miao, J.-F., Kroon, L.J.M., Vilaguerau De Arellano, J., Holt-Slag, A.A.M., Impacts of topography and land degradation on the sea breeze over eastern Spain (2003) Meteorol. Atmos. Phys., 84, pp. 157-170. , doi:10.1007/s00703-002-0579-1; 
Miglietta, M.M., Regano, A., An observational and numerical study of a flash-flood event over south-eastern Italy (2008) Nat. Hazards Earth Syst. Sci., 8, pp. 1417-1430. , doi:10.5194/nhess-8-1417-2008; 
Moncrieff, M.W., Green, J.S.A., The propagation and transfer properties of steady convective overturning in shear (1972) Q. J. Roy. Meteor. Soc., 98, pp. 336-352; 
Monteverdi, J.P., Doswell Iii., C.A., Lipari, G.S., Shear parameter thresholds for forecasting tornadic thunderstorms in northern and central California (2003) Weather Forecast., 18, pp. 357-370; 
Nastos, P.T., Matsangouras, J.T., Tornado activity in Greece within the 20th century (2010) Adv. Geosci., 26, pp. 49-51. , doi:10.5194/adgeo-26-49-2010; 
Nastos, P.T., Matsangouras, I.T., Composite Mean and Anomaly of Synoptic Conditions for Tornadic Days over North Ionian Sea (NW Greece) (2012) Advances in Meteorology, Climatology and Atmospheric Physics, pp. 639-645. , edited by: Helmis C. G. and Nastos, P. T, Springer Berlin Heidelberg, doi:10.1007/978-3-642-29172-2-91; 
Paul, F., A developing inventory of tornadoes in France (2000) Atmos. Res., 56, pp. 269-280; 
Paul, J.F., An inventory of tornadoes in France (1999) Weather, 54, pp. 217-219; 
Papadopoulos, A., Katsafados, P., Verification of operational weather forecasts from the POSEIDON system across the Eastern Mediterranean (2009) Nat. Hazards Earth Syst. Sci., 9, pp. 1299-1306. , doi:10.5194/nhess-9-1299-2009; 
Pytharoulis, I., High-resolution operational numerical weather forecasts for agrometeorological applications (2009) 6th Hellenic Conference of Agricultural Engineering, pp. 75-82. , 8-10 October, Thessaloniki, Greece, (in Greek); 
Rasmussen, E.N., Refined supercell and tornado forecast parameters (2003) Weather Forecast., 18, pp. 530-535; 
Rasmussen, E.N., Blanchard, D.O., A baseline climatology of sounding-derived super-cell and tornado forecast parameters (1998) Weather Forecast., 13, pp. 1148-1164; 
Schaefer, J.T., Severe thunderstorm fore-casting: A historical perspective (1986) Weather Forecast., 1, pp. 164-189; 
Shafer, C.M., Mercer, A.E., Doswell Iii., C.A., Richman, M.B., Leslie, L.M., Evaluation of WRF forecasts of tornadic and nontornadic outbreaks when initialized with synoptic-scale input (2009) Mon. Weather Rev., 137, pp. 1250-1271; 
Sioutas, M.V., A tornado and waterspout climatology for Greece (2011) Atmos. Res., 100, pp. 344-356; 
Sioutas, M.V., Nastos, P.T., Matsangouras, I.T., Floca, H.A., Meteorological Conditions Associated with Strong Tornadoes in Greece (2012) Advances in Meteorology, Climatology and Atmospheric Physics, pp. 293-299. , edited by: Helmis C. G. and Nastos, P. T, Springer Berlin Heidelberg, doi:10.1007/978-3-642-29172-2-42; 
Skamarock, W.C., Klemp, J.B., Dudhia, J., Gill, D.O., Barker, D.M., Duda, M.G., Huang, X.-Y., Powers, J.G., (2008) A Description of the Advanced Research WRF Version 3, , NCAR/TN-475; 
Stathopoulos, C., Kaperoni, A., Galanis, G., Kallos, G., Wind power prediction based on numerical and statistical models (2013) J. Wind Eng. Ind. Aerod., 112, pp. 25-38; 
Thompson, R.L., Edwards, R., Hart, J.A., Elmore, K.L., Markowski, P., Close proximity soundings within supercell environments obtained from the Rapid Update Cycle (2003) Weather Forecast., 18, pp. 1243-1261; 
Wang, W., Bruyere, C., Duda, M., Dudhia, J., Gill, D., Lin, H.-C., Michalakes, J., Mandel, J., (2010) ARW Version 3 Modeling System User{\textquoteright}s Guide, p. 352. , NCAR-MMM; 
Weisman, M.L., Klemp, J.B., The dependence of numerically simulated convective storms on vertical wind shear and buoyancy (1982) Mon. Weather Rev., 110, pp. 504-520; 
Weisman, M.L., Klemp, J.B., The structure and classification of numerically simulated convective storms in directionally varying wind shear (1984) Mon. Weather Rev., 112, pp. 2479-2498
},
	month = {2014},
	pages = {1905 - 1919},
	publisher = {Copernicus GmbH},
	abstract = {Tornadoes have been reported in Greece over recent decades in specific sub-geographical areas and have been associated with strong synoptic forcing. While it has been established that meteorological conditions over Greece are affected at various scales by the significant variability of topography, the Ionian Sea to the west and the Aegean Sea to the east, there is still uncertainty regarding topography{\textquoteright}s importance on tornadic generation and development. The aim of this study is to investigate the role of topography in significant tornadogenesis events that were triggered under strong synoptic scale forcing over Greece. Three tornado events that occurred over the last years in Thebes (Boeotia, 17 November 2007), Vrastema (Chalkidiki, 12 February 2010) and Vlychos (Lefkada, 20 September 2011) were selected for numerical experiments. These events were associated with synoptic scale forcing, while their intensities were T4-T5 (on the TORRO scale), causing significant damage. The simulations were performed using the non-hydrostatic weather research and forecasting model (WRF), initialized by European Centre for Medium-Range Weather Forecasts (ECMWF) gridded analyses, with telescoping nested grids that allow for the representation of atmospheric circulations ranging from the synoptic scale down to the mesoscale. In the experiments, the topography of the inner grid was modified by: (a) 0\% (actual topography) and (b)-100\% (without topography), making an effort to determine whether the occurrence of tornadoes-mainly identified by various severe weather instability indices-could be indicated by modifying topography. The principal instability variables employed consisted of the bulk Richardson number (BRN) shear, the energy helicity index (EHI), the storm-relative environmental helicity (SRH), and the maximum convective available potential energy (MCAPE, for parcels with maximum (θe). Additionally, a model verification was conducted for every sensitivity experiment accompanied by analysis of the absolute vorticity budget. Numerical simulations revealed that the complex topography constituted an important factor during the 17 November 2007 and 12 February 2010 events, based on EHI, SRH, BRN, and MCAPE analyses. Conversely, topography around the 20 September 2011 event was characterized as the least significant factor based on EHI, SRH, BRN, and MCAPE analyses. {\textcopyright} 2014 Author(s).},
	keywords = {atmospheric circulation, complex terrain, Greece, numerical model, Synoptic meteorology, topographic effect, tornado},
	isbn = {15618633 (ISSN)},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-84905216605\&partnerID=40\&md5=a3f4e0c3dc67292f7409e82f095fae85},
	author = {Matsangouras, I. T. and Pytharoulis, I. and Nastos, P. T.}
}
