Characterizing the spatial and temporal variability of biophysical variables of a wheat crop using hyper-spectral measurements

The spatial extension to field scale of biophysical variables retrieval from radiometric measurements is addressed. Hyper-spectral measurements were acquired over a wheat field on 4 dates in 2000 with a CASI sensor. In 2002, the XYBION multi-spectral sensor (6 bands) was used to acquire images on 5 dates. For each year, ground measurements were performed at ground level to estimate green leaf area index and Cab (leaf chlorophyll content). Two methods of retrieving biophysical variables were tested. The inversion through radiative transfer modeling was used with hyperspectral measurements, whereas empirical relationships were used to estimate variables from XYBION data. The results were discussed in terms of spatial and temporal variations of the estimates.