TY - JOUR
T1 - A note on upscaling coniferous needle spectra to shoot spectral albedo
AU - Rautiainen, Miina
AU - Mõttus, Matti
AU - Yáñez-Rausell, Lucia
AU - Homolová, Lucie
AU - Malenovský, Zbyněk
AU - Schaepman, Michael E.
PY - 2012/2/15
Y1 - 2012/2/15
N2 - Mutual shading of needles in coniferous shoots and small-scale variations in needle area density both within and between shoots violate conventional assumptions used in the definition of the elementary volume in radiative transfer models. In this paper, we test the hypothesis if it is possible to scale needle spectral albedo up to shoot spectral albedo using only one structural parameter: the spherically averaged shoot silhouette to total area ratio (STAR). To test the hypothesis, we measured both structural and spectral properties of ten Scots pine (Pinus sylvestris) shoots and their needles. Our results indicate that it is possible to upscale from needle to shoot spectral albedo using STAR. The upscaling model performed best in the VIS and SWIR regions, and for shoots with high STAR values. As STAR is linearly related to photon recollision probability, it is also possible to apply the upscaling model as integral part of radiative transfer models.
AB - Mutual shading of needles in coniferous shoots and small-scale variations in needle area density both within and between shoots violate conventional assumptions used in the definition of the elementary volume in radiative transfer models. In this paper, we test the hypothesis if it is possible to scale needle spectral albedo up to shoot spectral albedo using only one structural parameter: the spherically averaged shoot silhouette to total area ratio (STAR). To test the hypothesis, we measured both structural and spectral properties of ten Scots pine (Pinus sylvestris) shoots and their needles. Our results indicate that it is possible to upscale from needle to shoot spectral albedo using STAR. The upscaling model performed best in the VIS and SWIR regions, and for shoots with high STAR values. As STAR is linearly related to photon recollision probability, it is also possible to apply the upscaling model as integral part of radiative transfer models.
KW - Photon recollision probability
KW - Pinus sylvestris
KW - Spectral invariants
KW - STAR
UR - http://www.scopus.com/inward/record.url?scp=84855448948&partnerID=8YFLogxK
U2 - 10.1016/j.rse.2011.10.019
DO - 10.1016/j.rse.2011.10.019
M3 - Article
AN - SCOPUS:84855448948
SN - 0034-4257
VL - 117
SP - 469
EP - 474
JO - Remote Sensing of Environment
JF - Remote Sensing of Environment
ER -