Links between large-scale anomalies, rainfall and wine quality in the Iberian Peninsula during the last three decades

Recent strong El Nino-Southern Oscillation (ENSO) signals have been identified in precipitation records from the Iberian Peninsula. Interannual association with ENSO accounts for more than half the total annual variance in selected stations of the south-east, with ENSO leading rainfall by one year. In contrast, association with the North Atlantic Oscillation (NAO) at the Westernmost stations is much lower (25%). The potential of simple linear models is tested in the ENSO-sensitive area, suggesting high capability of the Southern Oscillation Index (SOI) for predicting interannual rainfall fluctuations (mainly droughts and floods). Wine quality is associated with several factors, e.g. grape variety, soil type and processing, which can be considered invariable, mainly due to the strict regulations imposed by the quality regulating councils. Climate, however, has a great influence on resulting wine quality, and represents the most important source of variability at both short (day-to-day) and long (interannual) time scales. Over the last 30 years, high-quality harvests in the five main wine regions in Spain, show a high probability (P < 0.0002) of being associated with an El Nino event occurring the same year or the year before. NAO influence is not significant during the same period. Thus, apart from considering the role of local climatic conditions in certain regions, which favour the production of excellent wines, larger-scale climatic phenomena appear responsible for the year-to-year variations in quality.