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A new technique to measure the spectral properties of conifer needles
- Daughtry, C.S.T., Biehl, L.L., Ranson, K.J.
- Remote sensing of environment 1989 v.27 no.1 pp. 81
- Picea mariana, Magnolia grandiflora, spectral analysis, remote sensing, reflectance
- Careful measurements of the spectral properties of individual leaves are required to understand interactions of radiation with vegetation and to use effectively the data from future sensors with increasingly finer spectral resolution. Instruments capable of measuring the optical properties of leaves typically have integrating spheres with sample parts at least 10 mm in diameter. However, the leaves of many grasses and conifers are too small to cover completely the sample port. We describe a technique that enables the measurements of reflectance and transmittance of narrow leaves or needles with spectroradiometers equipped with a light source and integrating sphere. Measurement procedures and formulae for optical property calculations are presented. A test of the techniques resulted in absolute reflectance differences of 3 % or less when comparing optical properties measured for whole leaves and narrow strips cut from the leaves. Thus, these techniques can accurately estimate the spectral properties of small leaves.