ABSTRACT: Sugar and acid accumulation dynamics in grapes Vitis vinifera L. play a key role in the production of high-quality wines, and changes in mean climate and variability, expected in the coming decades, may affect these dynamics and result in poor grape yield and quality. Simulation models may be useful tools for predicting grape quality changes under warmer conditions and thus provide fundamental information to winemakers for future vineyard management. The grape simulation model UNIFI.GrapeML was calibrated to predict the performances of the Sangiovese grape variety under different climate forcing. The model was calibrated and validated against observed data (i.e. phenology, sugar and acid content) of Sangiovese grapes at 2 Italian sites (Susegana and Montalcino), showing satisfactory performances in predicting the main phenological phases and sugar and acid contents. Future climate was simulated using the LARS-WG downscaling procedure by considering possible increases of yearly temperature (ΔT) ranging from +1°C to +3°C (step = 0.5°C) with respect to the baseline. For each step, we considered that the temperature increase can be constant every month or can exhibit seasonality, i.e. the increase in temperature is more evident in spring-summer than autumn-winter, as projected for the Mediterranean region. The results indicate that, on average, a progressive increase of temperatures resulted in earlier phenological phases and an increasing trend of sugar content while acid content showed the opposite. This trend is more evident as seasonality in the change of temperature increases, highlighting possible distortion in the impact assessment of climate change when seasonality is not accounted for.

中文翻译：

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在未来气候下模拟桑娇维塞葡萄中糖和酸的含量：意大利案例研究

摘要：糖和酸积累动态葡萄葡萄L.在高品质葡萄酒的生产中起着关键作用，预计未来几十年平均气候和变异性的变化可能会影响这些动态，并导致葡萄单产和质量下降。仿真模型可能是预测温暖条件下葡萄品质变化的有用工具，因此可以为酿酒师提供基础信息，以进行未来的葡萄园管理。对葡萄模拟模型UNIFI.GrapeML进行了校准，以预测不同气候强迫下桑娇维塞葡萄品种的性能。该模型已针对意大利2个地点（Susegana和Montalcino）的桑娇维塞葡萄的观测数据（即物候，糖和酸含量）进行了校准和验证，在预测主要物候期以及糖和酸含量方面表现出令人满意的性能。T）相对于基准范围为+ 1°C至+ 3°C（步进= 0.5°C）。对于每个步骤，我们认为温度升高可以每月保持恒定，或者可以表现出季节性，即，如地中海地区所预计的那样，春夏季比秋冬季的温度升高更为明显。结果表明，平均而言，温度的逐渐升高导致物候早期，糖含量呈上升趋势，而酸含量则相反。随着温度变化的季节性增加，这种趋势更加明显，这突出了在不考虑季节性的情况下气候变化影响评估中可能出现的失真。