AIR FORCE CAMBRIDGE RESEARCH CENTER BEDFORD MA GEOPHYSICS RESEARCH DIV
The spectral reflectance of natural objects is taken from Krinovs measurements. Based on these data, the luminous reflectance albedo and the color parameters are computed for these objects. The results are compared with other published data. It is shown that most natural objects possess a dominant wavelength between 5700A and 5900A, i.e. in the greenish yellow part of the spectrum. Even for vegetative formations, as seen from a distance, the dominant wavelength is also in the greenish yellow spectral range, which is a surprising fact because one would expect a dominant green. This color is, however, a mixture of brown and green. The excitation purity of bare areas and soils is low 15-30, but it is higher for vegetative formations 25-50. Vertical formations such as forests, seen from directly above, reflect only a very small amount 2-3 of the light which falls upon them from the sun and sky, but as seen from the ground their reflectance is much higher about 8.