Atmospheric patterns for heavy rain events in the Balearic Islands

摘要

The Balearic Islands, as well as other Mediterranean regions, are occasionally affectedby heavy rain events, which can produce numerous damages. This study contributes toimprove the understanding of the dynamical mechanisms that produce heavy rain eventsby means of a classification of their related atmospheric patterns.Heavy rainfall dataset for the Balearic Islands and some gridded atmosphericparameters, derived from the HIRLAM-INM-0.5° analyses, were the data used in thisstudy. Heavy rain events were recorded at a set of pluviometric stations along the Balearicsfor a period of 9 years, from June 1995 to May 2004. The 1000 hPa and 500 hPageopotential heights (hereafter φ₁₀₀₀ and φ₅₀₀),as well as the 850 hPa temperature (T₈₅₀) were the fields utilizedin 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 atmosphericpatterns were finally obtained. Most of the patterns showed a strong relationship betweenheavy rain events and cyclones.