Influence of woody elements of a Norway spruce canopy on nadir reflectance simulated by the DART model at very high spatial resolution

Z. Malenovsky, E. Martin, L. Homolova, J.P. Gastellu-Etchegory, R. Zurita Milla, M.E. Schaepman, R. Pokorny, J.G.P.W. Clevers, P. Cudlin

Research output: Contribution to journalArticleAcademicpeer-review

80 Citations (Scopus)

Abstract

A detailed sensitivity analysis investigating the effect of woody elements introduced into the Discrete Anisotropic Radiative Transfer (DART) model on the nadir bidirectional reflectance factor (BRF) for a simulated Norway spruce canopy was performed at a very high spatial resolution (modelling resolution 0.2 m, output pixel size 0.4 m). We used such a high resolution to be able to parameterize DART in an appropriate way and subsequently to gain detailed understanding of the influence of woody elements contributing to the radiative transfer within heterogeneous canopies. Three scenarios were studied by modelling the Norway spruce canopy as being composed of i) leaves, ii) leaves, trunks and first order branches, and finally iii) leaves, trunks, first order branches and small woody twigs simulated using mixed cells (i.e. cells approximated as composition of leaves and/or twigs turbid medium, and large woody constituents). The simulation of each scenario was performed for 10 different canopy closures (CC = 50¿95%, in steps of 5%), 25 leaf area index (LAI = 3.0¿15.0 m2 m¿ 2, in steps of 0.5 m2 m¿ 2), and in four spectral bands (centred at 559, 671, 727, and 783 nm, with a FWHM of 10 nm). The influence of woody elements was evaluated separately for both, sunlit and shaded parts of the simulated forest canopy, respectively. The DART results were verified by quantifying the simulated nadir BRF of each scenario with measured Airborne Imaging Spectroradiometer (AISA) Eagle data (pixel size of 0.4 m). These imaging spectrometer data were acquired over the same Norway spruce stand that was used to parameterise the DART model.
Original languageEnglish
Pages (from-to)1-18
JournalRemote Sensing of Environment
Volume112
Issue number1
DOIs
Publication statusPublished - 2008

Keywords

  • leaf-area index
  • radiative-transfer models
  • net primary production
  • gross primary production
  • remotely-sensed data
  • modis-lai product
  • vegetation indexes
  • bidirectional reflectance
  • biophysical variables
  • spectral properties

Fingerprint Dive into the research topics of 'Influence of woody elements of a Norway spruce canopy on nadir reflectance simulated by the DART model at very high spatial resolution'. Together they form a unique fingerprint.

Cite this