WINETECH Technical Yearbook 2020

FIGURE 4. Heat map: November 2018 to March 2019: Hours experienced below 20°C, the areas less favourable for optimal photosynthetic activity (green). The greener areas could require more management practices for more optimal grapevine functioning.

FIGURE 5. Heat map: November 2018 to March 2019: Hours experienced between 25-30°C. More hours at 25-30°C (greener) are areas of optimal photosynthetic areas, the red areas have less hours at 25-30°C, hence would require more management inputs to ensure optimal photosynthesis.

between 15-30°C. Relative humidity showed the inverse trend, with observations at lower relative humidity increasing. The summer wind speeds were the highest in the first three seasons, with less light breezes at 0-2 m/s, but more hours at higher wind speeds of 4-10 m/s. The study confirmed the hypothesis that grapevine will respond to climate change

and continue to do so in the expression of phenology, growth and ripening. Grapevine performances are affected by the constant environmental parameters, despite the differences on vineyard and site level. The finer scale analysis of the climate profile, considering and accounting for the amount of hours at specific classes of temperature, wind and relative humidity with no

(10-20°C) decreased, and observations at warmer temperatures (20-40°C) increased over the four seasons. December cooler over the four seasons, less hours at higher temperatures (20-35°C), March warmed, decreased hours at lower temperatures. The winter months, July showed a slight trend of cooling, more hours at 5-10°C. Spring, September warmed withmore hours

Seasonal and within season variation (vintage effect) is better understood reviewing the hourly profile for each month. This highlights what part of the season is changing in the context of climate change, information that can be more closely linked to the grapevine responses (figure 3). January showed more noticeable seasonal and site differences, cooler temperatures

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