Hyperspectral chlorophyll indices sensitivity analysis to soil backgrounds in agrirultural aplications using field, Probe-1 and Hyperion data

This paper focuses on the evaluation and comparison of the sensitivity of several chlorophyll indices to bare soils optical property variations. To achieve our goal, field spectroradiometric measurements were used as well as hyperspectral data acquired with the Probe-1 airborne and Hyperion EO-1 satellite sensors. The field-based reflectance measurements were acquired above 90 bare soil plots with various optical properties and selected from different agricultural lands. Probe-1 and Hyperion data were spectrally and radiometrically calibrated as well as atmospherically corrected. After these pre-processing steps, sixty spectra of different bare soils with various optical properties were extracted from each dataset for use in the analysis. The obtained results show an excellent agreement between the accuracies estimated from field, airborne and satellite data. Independently from the data source and from the bare soil background, CARI, MCARI and TCARI indices are basically not sensitive to changes in soil optical properties with an RMSE less than 1% and will permit a better estimation of chlorophyll content in sparse crop cover environment.