Comparative Analysis of the Sensitivity of SAR Data in C and L Bands for the Detection of Irrigation Events

Comprehensive knowledge about irrigation timing is crucial for water resource management. This paper presents a comparative analysis between C- and L-band Synthetic Aperture Radar (SAR) data the detection of events. The was performed using C-band time series derived from Sentinel-1 (S1) satellite two images PALSAR-2 (ALOS-2) sensor acquired over irrigated grassland plots in Crau plain southeast France. S1 first analyzed as function rainfall backscattering coefficients both L C bands were then compared to difference date SAR image last event occurring before acquisition (Δt). Sensitivity 2 classes Normalized Difference Vegetation Index (NDVI ≤0.7 NDVI >0.7). main results showed that when vegetation moderately developed ≤0.7), temporal variation remains sensitive soil moisture dynamics events could be detected. C-VV signal decreases due drying out increases. For well-developed cover >0.7), sensitivity becomes dependent on crop type. Gramineae grass with longs stalks seedheads, band shows no correlation Δt absence contribution backscattered signal, contrary legume type, where good correspondence > 0.7. In contrast, coefficient regardless development characteristics, thus being more suitable than band. L-HH or types same decreasing pattern increase Δt, NDVI-values, presenting decrease high radar parameters. Finally, co-polarizations (L-HH C-VV) tend adequate HV cross-polarization, they show higher values.