Solar induced fluorescence measurements using a field spectroradiometer

This work analyses the capability of estimating solarinduced vegetation fluorescence with general purpose field spectroradiometers. The most common approach to measure vegetation fluorescence under field conditions is by means of the Fraunhoffer LineDepth (FLD) method. The objective of this work is to check the applicability of this method at the two oxygen absorption bands when using an ASD FieldSpec PRO spectrometer. To accomplish this goal, two types of measurements are acquired. The first one is the spectral curve of the leaf radiance, which is used by the FLD method and consists on the solar reflected light plus the induced vegetation fluorescence emission. The second measurement is the actual spectral curve of the solar induced fluorescence emission from plant leaves when filtering the incident solar radiation with a cyan filter. Based on these measurements some improvements in the FLD method are proposed to increase the accuracy of the retrieved values, which include more realistic hypotheses on th...