Systematic review of thermal remote sensing for water status and evapotranspiration assessment in vineyard

Vineyards are among the most globally significant cropping systems, and water stress is one of the major abiotic factors influencing both yield and grape quality. Adequate diagnosis of vine water status is, thus, imperative for efficient water management. In this context, thermal remote sensing enables monitoring large areas and the retrieval of indicators related to plant water stress and water use, providing useful information for decision support. This systematic review synthesizes the main applications of thermal remote sensing in viticulture for assessing vine water status and estimating Evapotranspiration (ET), using satellite and aerial platforms, while describing the most widely adopted workflows. These include (i) Surface Energy Balance model approaches for ET estimation, (ii) Crop Thermal Indexes for drought stress level assessment, and (iii) recent advances integrating Machine-Learning techniques. The literature highlights the strong potential of these approaches to identify different severities of water stress and to determine ET in large areas while also revealing recurring limitations associated with processing workflows, data calibration, as well as model transferability across sites and conditions. In addition, the need to identify thermal indicators that are closely linked to physiological variables is highlighted. Future research should focus on integrating these methods into operational Variable-Rate Irrigation strategies and Regulated Deficit Irrigation applications, with the aim of improving grape quality while safeguarding water resources.