Future shifting of grapevine phenological phases: Simulation using STICS model

Due to the increase in temperature in recent decades, the onset of the phenological phase in the grapevine is also getting earlier. Earlier occurrences of phenological phases make the vines more vulnerable to frost, increase the risk of temperature stress in the last stages of development, and affect the quality of the final harvest. Considering that the temperature will continue to rise in the future, further changes in the phenological cycle of the vines are also expected. Therefore, it is important to model the future appearances of phenological phases as accurately as possible. One of the ways to succeed in this is to use the crop model, such as the STICS (Simulateur mulTIdisciplinaire pour les Cultures Standard) model. STICS model has been developed since 1996 at INRA and has been widely used for grapevine phenology prediction.

In this research, the STICS model is coupled with daily output from climate models; three CORDEX Regional Climate Models’ (RCMs) simulations (CLMcom-CCLM4-8-17, SMHI-RCA4, CNRM-ALADIN5.3) for Croatian domain and varieties. All RCMs are forced by output from Global Climate Models (GCMs) with a moderate (RCP4.5) and a high-end (RCP8.5) greenhouse gas (GHG) scenarios. SMHI-RCA4 is driven by five different GCMs (CNRM-CERFACS-CNRM-CM5, ICHEC-EC-EARTH, IPSL-IPSL-CM5A-MR, MOHC-HadGEM2-ES and MPI-M-MPI-ESM-LR), CLM by four (CNRM-CERFACS-CNRM-CM5, ICHEC-EC-EARTH and MOHC-HadGEM2-ES, MPI-M-MPI-ESM-LR), and CNRM-ALADIN5.3 with one (CNRM-CERFACS-CNRM-CM5). All the simulations have horizontal grid spacing of 0.11◦. Phenological phases in the STICS model, for 4 cultivars (Graševina, Plavac Mali, Chardonnay, and Merlot) were parameterized using meteorological measurements and observations of phenological phases. Once satisfactory results have been obtained in the present climate, the STICS model was used to study the differences in the occurrence of phenological phases in the future climate compared to the controlled period 1971-2000. The results show that a shift in phenological phases is expected in the future, regardless of the cultivar. The robustness of future changes depends on the localization analyzed.