Abstract
Forest types differ in their hyperspectral anisotropy patterns mainly due to species-specific geometrical structure, spatial arrangement of canopies and subsequent shadow patterns. This paper examines the multi-angular, hyperspectral reflectance properties of typical hemiboreal forests during summer time using three simultaneous CHRIS PROBA (mode 3) scenes and stand inventory data from the Järvselja Training and Experimental Forestry District in southeastern Estonia. We investigated the magnitude and reasons for the differences in the anisotropy patterns of deciduous and coniferous stands at three backward viewing angles. A forest reflectance model (FRT) was used as a tool to provide a theoretical basis to the discussion, and to estimate the directional contribution of scattering from crowns and ground to total stand reflectance for the two forest types. The FRT model simulated successfully the HDRF (hemispherical-directional reflectance factor) curves of the study stands to match those obtained from the CHRIS image, yet it produced a smaller and less wavelength-dependent angular reflectance effect than was observed in the satellite image. The main results of this study provide new information for separating the spectral contribution of the forest floor (or understory layer) from the tree canopy layer: (1) the red edge domain was identified to have the largest contribution from forest understory, and (2) the more oblique the viewing angle, the smaller the contribution from the understory. In addition, coniferous stands were observed to have a specific angular effect at the red and red edge domain, possibly as a result of the hierarchical structure and arrangement of coniferous canopies.
| Original language | English |
|---|---|
| Pages (from-to) | 2627-2642 |
| Number of pages | 16 |
| Journal | Remote Sensing of Environment |
| Volume | 112 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 15 May 2008 |
| MoE publication type | A1 Journal article-refereed |
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Keywords
- Forest reflectance model
- FRT
- Hemiboreal
- Hyperspectral
- Multi-angular canopy reflectance
- VALERI
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Multi-angular reflectance properties of a hemiboreal forest : An analysis using CHRIS PROBA data. / Rautiainen, Miina; Lang, Mait; Mõttus, Matti; Kuusk, Andres; Nilson, Tiit; Kuusk, Joel; Lükk, Tõnu.
In: Remote Sensing of Environment, Vol. 112, No. 5, 15.05.2008, p. 2627-2642.Research output: Contribution to journal › Article › Scientific › peer-review
TY - JOUR
T1 - Multi-angular reflectance properties of a hemiboreal forest
T2 - An analysis using CHRIS PROBA data
AU - Rautiainen, Miina
AU - Lang, Mait
AU - Mõttus, Matti
AU - Kuusk, Andres
AU - Nilson, Tiit
AU - Kuusk, Joel
AU - Lükk, Tõnu
PY - 2008/5/15
Y1 - 2008/5/15
N2 - Forest types differ in their hyperspectral anisotropy patterns mainly due to species-specific geometrical structure, spatial arrangement of canopies and subsequent shadow patterns. This paper examines the multi-angular, hyperspectral reflectance properties of typical hemiboreal forests during summer time using three simultaneous CHRIS PROBA (mode 3) scenes and stand inventory data from the Järvselja Training and Experimental Forestry District in southeastern Estonia. We investigated the magnitude and reasons for the differences in the anisotropy patterns of deciduous and coniferous stands at three backward viewing angles. A forest reflectance model (FRT) was used as a tool to provide a theoretical basis to the discussion, and to estimate the directional contribution of scattering from crowns and ground to total stand reflectance for the two forest types. The FRT model simulated successfully the HDRF (hemispherical-directional reflectance factor) curves of the study stands to match those obtained from the CHRIS image, yet it produced a smaller and less wavelength-dependent angular reflectance effect than was observed in the satellite image. The main results of this study provide new information for separating the spectral contribution of the forest floor (or understory layer) from the tree canopy layer: (1) the red edge domain was identified to have the largest contribution from forest understory, and (2) the more oblique the viewing angle, the smaller the contribution from the understory. In addition, coniferous stands were observed to have a specific angular effect at the red and red edge domain, possibly as a result of the hierarchical structure and arrangement of coniferous canopies.
AB - Forest types differ in their hyperspectral anisotropy patterns mainly due to species-specific geometrical structure, spatial arrangement of canopies and subsequent shadow patterns. This paper examines the multi-angular, hyperspectral reflectance properties of typical hemiboreal forests during summer time using three simultaneous CHRIS PROBA (mode 3) scenes and stand inventory data from the Järvselja Training and Experimental Forestry District in southeastern Estonia. We investigated the magnitude and reasons for the differences in the anisotropy patterns of deciduous and coniferous stands at three backward viewing angles. A forest reflectance model (FRT) was used as a tool to provide a theoretical basis to the discussion, and to estimate the directional contribution of scattering from crowns and ground to total stand reflectance for the two forest types. The FRT model simulated successfully the HDRF (hemispherical-directional reflectance factor) curves of the study stands to match those obtained from the CHRIS image, yet it produced a smaller and less wavelength-dependent angular reflectance effect than was observed in the satellite image. The main results of this study provide new information for separating the spectral contribution of the forest floor (or understory layer) from the tree canopy layer: (1) the red edge domain was identified to have the largest contribution from forest understory, and (2) the more oblique the viewing angle, the smaller the contribution from the understory. In addition, coniferous stands were observed to have a specific angular effect at the red and red edge domain, possibly as a result of the hierarchical structure and arrangement of coniferous canopies.
KW - Forest reflectance model
KW - FRT
KW - Hemiboreal
KW - Hyperspectral
KW - Multi-angular canopy reflectance
KW - VALERI
UR - http://www.scopus.com/inward/record.url?scp=41449093901&partnerID=8YFLogxK
U2 - 10.1016/j.rse.2007.12.005
DO - 10.1016/j.rse.2007.12.005
M3 - Article
VL - 112
SP - 2627
EP - 2642
JO - Remote Sensing of Environment
JF - Remote Sensing of Environment
SN - 0034-4257
IS - 5
ER -