Characterization of extreme climate events over four winegrowing regions in Portugal

Abstract

Grape and wine production, an important economic activity in Portugal, is strongly affected by weather and climate and thus highly vulnerable to climate change. Increased risk of drought, especially in the Mediterranean region, northward shift of isotherms for killing winter frost and prolonged warmer growing seasons are expected to continue throughout the twenty-first century and are of relevance for viticulture. Grapevine phenology, quality and yield are very dependent on climate at regional scale, local scale (mesoclimate: influenced by altitude, slope aspect and nearness to water, wind) and microclimate scale (influenced by vine spacing, reflectance of radiation from soil, and canopy management). Regional climate has been the focus of climate change impacts’ assessments. At the local level, the impact of site selection and management increases, and this is important for potential adaptations to climate change. The present work aims at identifying weather extremes, occurring at vineyard scale in four Portuguese winegrowing regions: Alentejo, Dão, Douro and Vinho Verde. Climate data collection and analysis, from 2010 up to 2014, through a network of weather stations (3 per vineyard, 1 vineyard per region) was performed, each of the winegrowing Regions displaying very different weather patterns and geo-morphologies. Vineyard-scale incidence of extreme weather-related events (heat, drought, frost, wind, heavy downpour and hail) was evaluated and statistically analyzed. Within-vineyard measurements, and its mesoclimate modeling, together with the genetic diversity of the Portuguese grape varieties (343 different grape varieties officially allowed in Portugal for winemaking – Portaria n. 380/2012) should represent a significant advantage in facing the challenge of climate change.