Retrieval and validation of forest background reflectivity from daily Moderate Resolution Imaging Spectroradiometer (MODIS) bidirectional reflectance distribution function (BRDF) data across European forests

Research output: Contribution to journalArticle


Information about forest background reflectance is needed for accurate biophysical parameter retrieval from forest canopies (overstory) with remote sensing. Separating under- and overstory signals would enable more accurate modeling of forest carbon and energy fluxes. We retrieved values of the normalized difference vegetation index (NDVI) of the forest understory with the multi-angular Moderate Resolution Imaging Spectroradiometer (MODIS) bidirectional reflectance distribution function (BRDF)/albedo data (gridded 500 m daily Collection 6 product), using a method originally developed for boreal forests. The forest floor background reflectance estimates from the MODIS data were compared with in situ understory reflectance measurements carried out at an extensive set of forest ecosystem experimental sites across Europe. The reflectance estimates from MODIS data were, hence, tested across diverse forest conditions and phenological phases during the growing season to examine their applicability for ecosystems other than boreal forests. Here we report that the method can deliver good retrievals, especially over different forest types with open canopies (low foliage cover). The performance of the method was found to be limited over forests with closed canopies (high foliage cover), where the signal from understory becomes too attenuated. The spatial heterogeneity of individual field sites and the limitations and documented quality of the MODIS BRDF product are shown to be important for the correct assessment and validation of the retrievals obtained with remote sensing.


  • Jan Pisek
  • Angela Erb
  • Lauri Korhonen
  • Arnaud Carrara
  • Edoardo Cremonese
  • Matthias Cuntz
  • Silvano Fares
  • Giacomo Gerosa
  • Thomas Grünwald
  • Niklas Hase
  • Michal Heliasz
  • Andreas Ibrom
  • Alexander Knohl
  • Johannes Kobler
  • Bart Kruijt
  • Holger Lange
  • Leena Leppänen
  • Jean-Marc Limousin
  • Francisco Ramon Lopez Serrano
  • Denis Loustau
  • Petr Lukeš
  • Lars Lundin
  • Riccardo Marzuoli
  • Leonardo Montagnani
  • Johan Neirynck
  • Matthias Peichl
  • Corinna Rebmann
  • Eva Rubio
  • Margarida Santos-Reis
  • Crystal Schaaf
  • Marius Schmidt
  • Guillaume Simioni
  • Kamel Soudani
  • Caroline Vincke
External organisations
  • University of Tartu
  • University of Massachusetts
  • University of Eastern Finland
  • Fundacion Centro de Estudios Ambientales del Mediterraneo (CEAM)
  • Environmental Protection Agency of Aosta Valley
  • University of Lorraine
  • Catholic University of the Sacred Heart, Brescia
  • Dresden University of Technology
  • Helmholtz Centre for Environmental Research (UFZ)
  • Technical University of Denmark
  • University of Göttingen
  • Austrian Federal Environmental Agency
  • Wageningen University
  • Norwegian Institute of Bioeconomy Research (Nibio)
  • Finnish Meteorological Institute
  • University of Castilla La Mancha
  • Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE)
  • Swedish University of Agricultural Sciences
  • Free University of Bozen-Bolzano
  • Research Institute for Nature and Forest
  • Jülich Research Centre
  • University of Paris-Saclay
  • Catholic University of Louvain
  • CNR: National Research Council of Italy
  • Paul Valéry University of Montpellier
  • Global Change Research Centre of the Czech Academy of Sciences
  • Forest Services, Autonomous Province of Bolzano
  • University of Lisbon
  • Agro ParisTech
  • University of Montpellier
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Forest Science
  • Physical Geography
Original languageEnglish
Article number34
Pages (from-to)621-635
Number of pages15
Issue number2
Publication statusPublished - 2021 Jan 27
Publication categoryResearch