Water Stress Detection Over Irrigated Wheat Crops in Semi-Arid Areas using the Diurnal Differences of Sentinel-1 Backscatter

This work aims to investigate the sensitivity of the diurnal differences of radar backscatter to diurnal changes in the vegetation water content (VWC). Sentinel-1 backscattering coefficient differences between two orbits (morning and evening) are analyzed over an irrigated and voluntarily stressed wheat field. A physical model of backscatter prediction is evaluated for wheat and used to examine the sensitivity of radar differences to the VWC for a range of surface soil moisture and biomass conditions. Results highlight the potential of C-band diurnal differences for the monitoring the water stress over agricultural canopies