Structure and trends in climate parameters affecting winegrape production in northeast Spain

This study examined the structure and trends of climate parameters important to winegrape production from 1952 to 2006 in the Alt Penedes, Priorat, and Segria regions of NE Spain. Average and extreme temperature and precipitation characteristics from 3 stations in the regions were organized into annual, growing season, and phenological growth stage periods and used to assess potential impacts on vineyard and wine quality, and changes in varietal suitability. Results show an overall growing season warming of 1.0 to 2.2 degrees C, with significant increases in heat accumulation indices that are driven mostly by increases in maximum temperature (average Tmax, number of days with Tmax > 90th percentile, and number of days with Tmax > 30 degrees C). Changes in many temperature parameters show moderate to strong relationships with vine and wine parameters in the 3 regions, including earlier phenological events concomitant with warmer growing seasons, higher wine quality with higher ripening diurnal temperature ranges, and reduced production in the warmest vintages. While trends in annual and growing season precipitation were not evident, precipitation during the bloom to veraison period declined significantly for all 3 sites, indicating potential soil moisture stress during this critical growth stage. Shorter-term analysis of crop evapotranspiration (ETc) reveals that the current impact per 1 degrees C of growing season (Apr to Oct) warming is an increase in water demands in the region by 6 to 14%. These observations, combined with climate projections, indicate potential disruption of climate-variety balance, increasing water stress, and challenges in producing quality wines without the adoption of appropriate adaptive measures.