Assessing future irrigation needs in vineyard living labs through microclimate modelling and climate projections

Understanding vineyard scale microclimate variability is essential for adapting viticulture to climate change and increasing water scarcity. This study applies a high-resolution microclimate modelling framework to assess future irrigation requirements in two Mediterranean vineyard living labs, in the Douro Region and Alentejo. The approach integrates the NicheMapR microclimate model, hourly local meteorological observations, ERA5-Land reanalysis, and a high-resolution Digital Elevation Model to generate climate variables at 10m spatial resolution. Local station data are used to bias-correct ERA5-Land through quantile mapping, while topographic effects (elevation, slope, aspect, shading and horizon angles) are explicitly represented via the Digital Elevation Model. The resulting 10 m microclimate outputs are then used to bias-correct EURO-CORDEX regional climate model ensembles, producing vineyard-specific future climate projections. These climate datasets are subsequently used in the STICS crop model to simulate vineyard water balance and irrigation requirements. Irrigation needs are assessed for four climate scenarios (RCP4.5 and RCP8.5, mid- and end-century) under four water stress levels (20%, 40%, 60% and 80%). Results show increasing irrigation demand and variability under higher radiative forcing, with distinct responses between the two vineyards reflecting differences in local microclimate and atmospheric demand. In addition, viticulture climate extreme and bioclimatic indices are derived at the 10m scale, providing insights for vineyard-scale irrigation planning and climate adaptation. Differences between the Douro and Alentejo vineyards emphasise the role of local microclimate in modelling irrigation needs, reinforcing the importance of site-specific adaptation strategies. This work highlights the value of combining microclimate modelling, crop modelling, and bias-corrected climate projections to support sustainable vineyard management under future climate change.

Acknowledgements: Research funded by Vine & Wine Portugal–Driving Sustainable Growth Through Smart Innovation, PRR & NextGeneration EU, Agendas Mobilizadoras para a Reindustrialização, Contract Nb. C644866286-011. The authors acknowledge National Funds by FCT – Portuguese Foundation for Science and Technology, under the projects UID/04033/2025: Centre for the Research and Technology of Agro-Environmental and Biological Sciences (https://doi.org/10.54499/UID/04033/2025) and LA/P/0126/2020 (https://doi.org/10.54499/LA/P/0126/2020).