Measurements of Seasonal Changes in Vegetation Reflectance Spectra

Seasonal changes in leaf reflectance and spectral indices are measured for leaves from a Norway maple tree growing in eastern New England. Measurements were made in the laboratory between September 11 and November 2, 2007. Reflectance measurements of one and four leaf stacks were made using an ASD spectrometer. The four leaf stacks were optically thicker than one leaf stacks and appear to be closer to typical canopy reflectance. Time series measurements for NDVI and water indices show very small standard deviation for individual days, with greater variability between measurement days. Compared to measurements reported in the literature, the measurements show a relatively small seasonal range. Much of the observed day-to-day variability may be due to differences between individual leaves.