Analysis of the impact of climate change on grapevines in Turkey using heat unit accumulation-based indices

Temperature is the most important factor influencing grapevine phenology and yield. Various indices have been developed that deal with the temperature sums that grapevines are exposed to during growth and maturation. With the help of these indices, predictions are made about whether the grapes will grow in a certain region and the quality of the grapevines. In this study, the future impacts of climate change on viticultural conditions in Turkey were projected by using Huglin index (HI), Winkler index (WI), and cool night index (CI). Under the RCP8.5 scenario, HI, WI, and CI indices for the future period of 2022-2050 were calculated for Turkey at 10 km spatial resolution with the RegCM4.4 model and compared with the 1972-2000 reference period. As a result of the study, a substantial increase in CI, HI, and WI and at least one level of categorical change were observed in the climatic conditions of the next 30 years in Turkey. These categorical shifts in CI, HI, and WI indicate that there may be changes in the geographical pattern of grapevine species grown in Turkey as well as the aroma and quality.