Applying satellite measurements to assess irrigation needs and support agricultural sustainability in Central Chile

Global food demand is expected to rise substantially in the coming decades and require increased agricultural production. However, agroecosystems are already facing more frequent, more intense extreme events. This is a particularly critical issue in Central Chile, whose agricultural sector depends heavily on irrigation and surface flow withdrawals. For more than a decade, the region has been affected by a megadrought, which poses a risk to irrigated agriculture. In this context, managing water resources and evaluating irrigation needs are vital. Because in-situ measurements of evapotranspiration are scarce, satellite-based methods have the potential to fill gaps in coverage and augment existing monitoring capabilities. For these reasons, we explored how publicly available Earth observations from space can be best utilized to accurately assess crop water use. Our study leveraged evapotranspiration measurements from the Terra Moderate Resolution Imaging Spectroradiometer (MODIS) and ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) along with vegetation greenness from NASA Landsat 8 and 9 Operational Land Imagers. We compared and validated the remotely sensed information acquired against in-situ data. We then expanded our analyses more broadly to capture regional patterns across the Aconcagua and Maipo basins, whose rivers irrigate some of the most populous parts of Chile. In addition, we investigated potential temporal trends to better understand crop-water dynamics and climate-related changes. Harnessing the high resolution of satellite observations, this study provided new information on irrigation needs and has the potential to inform decisions for shared prosperity around limited water resources in Central Chile. This work was made possible by Chile's Centro de Información de Recursos Naturales (CIREN) and the University of Virginia's Center for Global Health Equity.