Natural Hazards and Earth System Science www.nat-hazards-earth-syst-sci.net 1561-8633 1684-9981 7 1 2007 10.5194/nhess-7-41-2007 http://www.nat-hazards-earth-syst-sci.net/7/41/2007/ http://www.nat-hazards-earth-syst-sci.net/7/41/2007/nhess-7-41-2007.html http://www.nat-hazards-earth-syst-sci.net/7/41/2007/nhess-7-41-2007.pdf 41 56 2007-01-15 Analysis of the environments of seven Mediterranean tropical-like storms using an axisymmetric, nonhydrostatic, cloud resolving model L. Fita lluis.fita@uib.es R. Romero A. Luque K. Emanuel C. Ramis Grup de Meteorologia, Departament de Física, Universitat de les Illes Balears, Palma de Mallorca, Spain Program in Atmospheres, Oceans, and Climate, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA Tropical-like storms on the Mediterranean Sea are occasionally observed on satellite images, often with a clear eye surrounded by an axysimmetric cloud structure. These storms sometimes attain hurricane intensity and can severely affect coastal lands. A deep, cut-off, cold-core low is usually observed at mid-upper tropospheric levels in association with the development of these tropical-like systems. In this study we attempt to apply some tools previously used in studies of tropical hurricanes to characterise the environments in which seven known Mediterranean events developed. In particular, an axisymmetric, nonhydrostatic, cloud resolving model is applied to simulate the tropical-like storm genesis and evolution. Results are compared to surface observations when landfall occurred and with satellite microwave derived wind speed measurements over the sea. Finally, sensitivities of the numerical simulations to different factors (e.g. sea surface temperature, vertical humidity profile and size of the initial precursor of the storm) are examined. Bister, M. and Emanuel, K A.: Dissipative Heating and Hurricane Intensity, Meteor. Atmos. Physics, 50, 2662–2682, 1998. Campins, J., Genovés, A., Jansà, A., Guijarro, J A., and Ramis, C.: A catalogue and a classification of surface cyclones for the western Mediterranean, Int. J. Climatol., 20, 969–984, 2000. Emanuel, K.: Tropical Cyclones, Annu. Rev. Earth. Planet. Sci., 31, 75–104, 2003. Emanuel, K A.: An Air-Sea Interaction Theory for Tropical Cyclones. Part I: Steady-State Maintenance, J.Atmos. Sci., 43, 585–604, 1986. Emanuel, K A.: Genesis and maintenance of "Mediterranean hurricanes", Adv. in Geos., 2, 217–220, 2005. Grell, G., Dudhia, J., and Stauffer, D.: A description of the fifth-generation Penn State/NCAR mesoscale model (MM5), NCAR Technical Note, NCAR/TN-398+STR, 117pp, 1994. Homar, V., Romero, R., Stensrud, D., Ramis, C., and Alonso, S.: Numerical diagnosis of a small, quasi-tropical cyclone over the western Mediterranean: Dynamical vs. boundary factors, Q. J. R. Meteorol. Soc., 129, 1469–1490, 2003. Hoskins, B J., McIntyre, M E., and W., R A.: On the use and significance of isentropic potential vorticity maps, Q. J. R. Meteo. Soc., 111, 877–946, 1985. Jordan, C L.: Mean Soundings for the West Indies Area, J. Meteor., 15, 91–97, 1958. Lagouvardos, K., Kotroni, V., Nickovic, S., Jovic, D., and Kallos, G.: Observations and model simulations of a winter sub-synoptic vortex over the central Mediterranean, Meteorol. Appl., 6, 371–383, 1999. Pytharoulis, I., Craig, G C., and Ballard, S P.: The hurricane-like Mediterranean cyclone of January 1995, Meteorol. Appl., 7, 261–279, 2000. Rasmussen, E. and Zick, C.: A subsynoptic vortex over the Mediterranean with some resemblance to polar lows, Tellus A, 39, 408–425, 1987. Reiter, E R.: Handbook for Forecasters in the Mediterranean: Weather Phenomena of the Mediterranean Basin, Environmental Prediction Research Facility, Naval Postgraduate School, Monterey, CA, 1975. Romero, R. and Emanuel, K.: Space-time probability density of Mediterranean hurricane genesis in the light of an empirical tropical index, 5a Assamble Hispano-Portuguesa de Geodesia y Geofisica, (Spanish), 4, 2006. Rotunno, R. and Emanuel, K.: An Air-Sea Interaction Theory for Tropical Cyclones. Part II: Evolutionary Study Using a Nonhydrostatic Axisymmetric Numerical Model, J. Atmos. Sci., 44, 542–561, 1987. Thorpe, A J.: Synoptic scale disturbances with circular symmetry, Mon. Wea. Rev., 114, 1384–1389, 1986. Tudur\'\i E. and Ramis, C.: The Enviromments of Significant Convective Events in the Western Mediterranean, Weather and Forecasting, 12, 294–306, 1997.