## 3 Results
### Grape Berry Parameters versus Climate
#### 3.2.1 Berry Weight  
The TON berry weight at maturity was negatively correlated with monthly temperatures of June, July and August in the four vineyards (Dao, Alentejo, Douro-C and Douro-D, Figure 2). Moderate to very strong negative correlations were observed with TG (\(-0.50\) to \(-0.83\)) and TX (\(-0.56\) to \(-0.81\)) in Alentejo, with August temperatures showing more influence on berry weight. Moreover, in Dao and Douro-C, moderate negative correlations were also found with TG and TX in July. In Douro-D, correlations were weak for all temperatures and months analysed. In general, in all sites, TN showed a much weaker influence on berry weight than TG and TX. Precipitation during the maturation period (July to September) increased berry weight, except in the Dao region, while a very strong positive correlation was observed in Alentejo (0.81). Similar to TON, the ARA berry weight tended to be negatively correlated with temperatures but, in general, correlations were weak to moderate (Figure 3). Berry weights in Alentejo and Douro-C were more correlated to June temperatures, while in Dao, July temperatures were more influential. In Douro-D, very weak correlations were observed between temperature and berry weight. A strong positive correlation between berry weight and precipitation during the maturation period (July to September) was only observed in Douro-C (0.79).  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Vineyard** & **GST (\({}^{\circ}\)C)** & **JJA TG (\({}^{\circ}\)C)** & **JJA TX (\({}^{\circ}\)C)** & **JJA TN (\({}^{\circ}\)C)** & **RR (mm)** \\ \hline
**1. Douro-D** & 20.5 & 24.4 & 31.8 & 16.2 & 563 \\
**2. Douro-C** & 18.2 & 21.9 & 29.0 & 14.0 & 681 \\
**3. Dão** & 18.1 & 21.3 & 29.5 & 12.9 & 992 \\
**4. Alentejo** & 21.1 & 24.2 & 33.1 & 15.5 & 637 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Climatic characterization of the studied sites over the baseline period of 1991–2017. RR: annual mean precipitation (in mm); GST: growing season (April–October) mean temperature (in \({}^{\circ}\)C); JJA TG/TX/TN: summertime mean (June–August) of the daily mean (TG), maximum (TX) and minimum (TN) temperature (in \({}^{\circ}\)C).  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & **Weight of** & **Titatable** & & **Potential** & & **Anthocyanins** \\
**Vineyard** & **100 Berries** & **Acidity** & **pH** & **Alcohol** & **TPI** & **Anthocyanins** \\  & **(g)** & **(g/L T.A.) * & & **(17 g/1\%)** & & **(mg/L)** \\ \hline
**Douro-D (TON)** & 135 & 4.35 & 3.85 & 12.70 & 40.80 & 282 \\
**Douro-C (TON)** & 189 & 5.80 & 3.55 & 12.80 & 41.25 & 301 \\
**Dão (TON)** & 150 & 5.05 & 3.72 & 12.00 & 40.95 & 426 \\
**Alentejo (TON)** & 135 & 4.10 & 3.86 & 13.50 & 55.50 & 419 \\
**Douro-D (ARA)** & 163 & 3.40 & 3.94 & 14.70 & 40.90 & 306 \\
**Douro-C (ARA)** & 222 & 4.40 & 3.77 & 14.40 & 39.80 & 369 \\
**Dão (ARA)** & 219 & 4.35 & 3.86 & 13.90 & 37.80 & 399 \\
**Alentejo (ARA)** & 167 & 3.70 & 4.06 & 14.75 & 53.30 & 503 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Characterization of the selected berry quality parameters. The values represent the average of each berry quality parameter. TON—Touriga Nacional; ARA—Aragonez; * g of tartaric acid equivalents per L of juice.