Figure 4.

Illustration of the processed radar signal differences (dB) for all dates, with the driest radar signals shown as a function of NDVI for all (100 m × 100 m) cells in the Urgell area. Each point corresponds to a single radar signal difference $\mathsf{\Delta }{\mathsf{\sigma }}_{{}_{(\mathrm{i},\mathrm{j})}}^{\mathrm{NDVI}}$ for a cell (i,j).