High-Resolution (1km Daily) Potential Evapotranspiration Dataset Over Europe and the Mediterranean Region

High-resolution climate data significantly enhance the accuracy and understanding of water budgets, particularly in mountainous regions. Evapotranspiration (ET), the largest terrestrial water flux, is a critical parameter for surface water modelling and monitoring climate change impacts on water resources and agriculture. Its influence is especially pronounced in Europe and the Mediterranean, recognized as climate change hotspots.

This study presents a high-resolution (1 km daily) Potential Evapotranspiration (PET) dataset, derived from a combination of ground-based and remote sensing data and adjusted with daily crop growth coefficients. Covering Europe and the Mediterranean region from 2004 to 2022, the dataset is validated through regional, basin, and local scales. Validation is performed using triple collocation metrics combining the PET-1km product, GLEAM (28 km) and hPET (11 km), as well as with daily measurements from 38 eddy covariance (EC) flux tower stations within the study domain. At the basin scale, the Adige River basin in the Italian Alps is modeled using the Adige Hydrological Digital Twin, incorporating PET-1 km as an input component.

Regional-scale validation highlights the superior performance of the PET-1 km dataset, achieving better results in 86.7% of the study area compared to GLEAM and hPET. Site-scale validation against EC measurements indicates a high correlation coefficient (0.82) and a low RMSE (1.08 mm/day). Basin-scale validation in the Adige basin reveals improved modelling of water cycle components compared to previous findings on the same study area.

This high-resolution PET dataset offers valuable insights for climate and hydrological studies, advancing water resource management and climate adaptation strategies in this crucial region.