Efeito do fenômeno El Niño Oscilação Sul (ENOS) na produtividade e na qualidade de uvas europeias produzidas em Santana do Livramento, Rio Grande do Sul

Abstract

The commercial production of grapes and wines, both from a quantitative and a qualitative point of view, is strongly dependent on meteorological conditions, their average trends and their seasonal and inter-annual variability. The El Niño Southern Oscillation (ENSO) – which comprises three phases, neutral, El Niño and La Niña – is a known source of variability in the climate of southern Brazil, where the municipality of Santana do Livramento is located. The objective of this study was to know the influences of ENSO on the winegrowing climate, as well as on the yield and quality (sugar accumulation) of grapes produced in the Santana do Livramento. This study was divided into three parts, organized into three articles. The first article characterized the regional viticultural climate, especially regarding its variability in relation to the ENSO phases. Large variability associated with the ENSO was observed among the production cycles under study. El Niño events presented conditions of greater humidity and less availability of thermal energy, while the opposite patterns were observed under the influence of La Niña. The second article elucidated the correlations between yield and the temperature of surface waters in the Pacific Ocean (correlating it with the occurrence of El Niño and La Niña events of different intensities). Strong El Niño events showing earlier consolidation were generally the most correlated with large crop failures. On the other hand, this early consolidation also makes it possible to warn, before the beginning of spring, about the potential adverse conditions of the upcoming production cycle. The third article analyzed yield and sugar accumulation and its correlation with of the ENSO. The El Niño events to reduce both yield and sugar accumulation, patterns opposite to those observed in La Niña periods.