Advances in Geosciences www.adv-geosci.net 1680-7340 1680-7359 12 Mediterranean storms and extreme events in an era of climate change 2007 10.5194/adgeo-12-27-2007 http://www.adv-geosci.net/12/27/2007/ http://www.adv-geosci.net/12/27/2007/adgeo-12-27-2007.html http://www.adv-geosci.net/12/27/2007/adgeo-12-27-2007.pdf 27 32 2007-06-28 Atmospheric patterns for heavy rain events in the Balearic Islands A. Lana lana@cmima.csic.es J. Campins A. Genovés A. Jansà Centre Meteorològic de les Illes Balears, Instituto Nacional de Meteorología, Spain The Balearic Islands, as well as other Mediterranean regions, are occasionally affected by heavy rain events, which can produce numerous damages. This study contributes to improve the understanding of the dynamical mechanisms that produce heavy rain events by means of a classification of their related atmospheric patterns. Heavy rainfall dataset for the Balearic Islands and some gridded atmospheric parameters, derived from the HIRLAM-INM-0.5° analyses, were the data used in this study. Heavy rain events were recorded at a set of pluviometric stations along the Balearics for a period of 9 years, from June 1995 to May 2004. The 1000 hPa and 500 hPa geopotential heights (hereafter φ1000 and φ500), as well as the 850 hPa temperature (T850) were the fields utilized in the classification. By means of a principal components analysis (PCA) the number of variables was reduced. The cluster analysis (CA) was then applied on those new variables and eight atmospheric patterns were finally obtained. Most of the patterns showed a strong relationship between heavy rain events and cyclones. Anderberg, M. R.: Cluster Analysis for Applications, Academic Press, New York, 1973. Campins, J., Jansà , A., and Genovés, A.: Heavy rain and strong wind events and cyclones in the Balearics, Adv. Geosci., 7, 73–77, 2006. Campins, J., Jansà, A., and Genovés, A.: Three-dimensional structure of Western Mediterranean cyclones, Int. J. Climatol., 26, 323–343, 2006. Houssos, E. and Bartzokas, A.: Extreme precipitation events in NW Greece, Adv. Geosci., 7, 91–96, 2006. Jansà, A., Genovés, A., and Garc\'ia-Moya, J. A.: Western Mediterranean cyclones and heavy rain. Part I: Numerical experiment concerning the Piedmont flood case, Meteorol. Appl., 7, 323–333, 2000. Jansà, A., Genovés, A., Picornell, M. A., Campins, J., Riosalido, R., and Carretero, O.: Western Mediterranean cyclones and heavy rain. Part II: Statistical approach, Meteorol. Appl., 8, 43–56, 2001. Romero, R., Sumner, G., Ramis, C., and Genovés, A.: A classiﬁcation fo the atmospheric circulation patterns producing significant daily rainfall in the Spanish Mediterranean area, Int. J. Climatol., 19, 765–785, 1999. Yarnal, B.: Synoptic Climatology in Environmental Analysis, Belhaven Press, London, 1993.