Using Multispectral and Radar Imagery to Estimate Citrus Water Requirements in the Context of Climate Change in the MENA Region

Citrus farming in the MENA region faces increasing challenges due to climate-induced water scarcity. Ensuring precise and efficient irrigation is essential to sustain production under semi-arid conditions. This chapter presents a remote sensing-based method that combines multispectral (Sentinel-2) and radar (Sentinel-1) imagery to estimate the water requirements (ETc) of citrus trees in southern Morocco over a five-year period. Vegetation indices such as NDVI and radar-based indices like VH-VV were used to compute crop coefficients (Kc), which were then coupled with meteorological data to estimate ETc. Radar imagery, less affected by weather conditions, provided high accuracy (RMSE = 0.050) and continuous monitoring. Spatial and temporal variability in water demand was effectively captured, enabling targeted irrigation strategies. This approach offers a scalable and cost-effective tool to improve water management and resilience in agriculture, contributing to key climate adaptation priorities in the MENA region.