Geospatial information for sustainable food systems

Remote sensing determination of evapotranspiration

Year published: 30/10/2023

The Near East and North Africa (NENA) Region has long faced water scarcity due to natural causes. Still, factors like population growth, food security policies, and socioeconomic development have worsened the situation in recent decades. Climate change and the food insecurity resulting from the war in Ukraine have further strained the already limited water resources in the region.

To address these challenges, countries in the NENA Region seek ways to allocate scarce water resources effectively. They aim to improve water accounting, monitor water usage in strategic hydrological systems, and enhance water productivity and efficiency to save and redistribute water. One crucial aspect to consider in these efforts is water consumption, particularly in irrigated agriculture, which utilizes over 85 percent of renewable freshwater resources while remaining vital to the sustainability of the food sector and farming systems.

Given the significant spatial scales involved, satellite remote sensing technology has become a valuable tool in determining evapotranspiration–water consumption. The Food and Agriculture Organization (FAO) Regional Initiative on Water Scarcity for the Near East and North Africa (WSI) has gathered top experts in evapotranspiration determination through satellite remote sensing to guide water stakeholders in the region. This initiative has also expanded to other FAO regions through the inter-Regional Technical Platform on Water Scarcity (iRTP-WS).

To facilitate knowledge sharing, a series of twenty-five webinars were organized, fostering dialogue between experts and water actors. Additionally, this publication summarizes the outcomes of the webinars and provides further analysis and insights on satellite remote sensing determination of evapotranspiration.

The publication aims to update the knowledge and enhance the capacity of water professionals, raise awareness of the strengths and limitations of remote sensing models and databases for evapotranspiration, and clarify operational aspects such as spatial and temporal resolutions and accuracy. Ultimately, it serves as a valuable reference for water actors and professionals working towards sustainable water resource management.