Analyses of agroclimatic indices applied to Croatian grapevine growing regions in present and in the future climate

The factors which significantly affect the viticulture are temperature and precipitation. Consequently, viticulture is highly affected by climate change. The agroclimatic indices describe the suitability of particular region for wine production. For the purpose of this study six indices (Average growing season temperature, Growing degree days, Huglin index, Dryness index, Cool night index and Composite index) were calculated using daily output from three CORDEX Regional Climate Models’ (RCMs) simulations (CLMcom-CCLM4-8-17, SMHI-RCA4, CNRM-ALADIN5.3) for Croatian domain and using daily near-surface measurements (minimum, maximum and mean temperature, relative humidity, wind speed and total precipitation). All RCMs are forced by Global Climate Models (GCMs) with a moderate (RCP4.5) and a high-end (RCP8.5) greenhouse gass (GHG) scenario. All the simulations have horizontal grid spacing of 0.11◦. First historical analysis was done comparing two periods (1961-1990 and 1988-2017) to establish present situation and to determine changes in indices so far. Then, in order to determine future changes in agroclimatic indices, spatial distribution of the indices in historical runs (1971-2000) is compared to three different 30-year periods (2011-2040, 2041-2070 and 2070-2099). The sign and the robustness of future changes depend on the location/region analyzed. The results revealed good skill of the RCM in simulating bioclimatic characteristics. The results also show, whether the part of the country, which is suitable for grape cultivation in present climate (1971-2000) continues to be favorable in the future. We can also reveal whether some other parts of Croatia become suitable for cultivating grapevine in the future climate.