Natural Hazards and Earth System Science www.nat-hazards-earth-syst-sci.net 1561-8633 1684-9981 9 1 2009 10.5194/nhess-9-241-2009 http://www.nat-hazards-earth-syst-sci.net/9/241/2009/ http://www.nat-hazards-earth-syst-sci.net/9/241/2009/nhess-9-241-2009.html http://www.nat-hazards-earth-syst-sci.net/9/241/2009/nhess-9-241-2009.pdf 241 250 2009-02-26 Indices of precipitation extremes in Southern Portugal – a geostatistical approach R. Durão rmdurao@ist.utl.pt M. J. Pereira A. C. Costa J. M. Côrte-Real A. Soares CERENA, Instituto Superior Técnico, Lisboa, Portugal ISEGI, Universidade Nova de Lisboa, Lisboa, Portugal ICAM, Universidade de Évora, Évora, Portugal Most of the actual studies and previews of future rainfall patterns, based on past observed records for Mediterranean climate areas, focus on the decline of the rainfall amounts over the years, and also on the increase of the frequency of heavy/intense rainfall events particularly in the winter season. These changes in heavy rainfall events may have severe implications and impacts on soil erosion resulting in increased soil degradation risks. <br><br> The objective of the present work is to evaluate the spatial distribution of extreme precipitation events in Southern Portugal, using a geostatistical approach to assess the relationships between spatial and temporal extreme rainfall patterns. The used dataset comprises a set of 105 stations' records of daily precipitation within the period 1960–1999. Two indices of extreme precipitation were selected to be computed based on the daily precipitation observation series: one representing the frequency of extremely heavy precipitation events (R30) and another one characterizing flood events (R5D). <br><br> The space-time patterns of the precipitation indices were evaluated and simulated using a geostatistical approach. 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