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Full-Text Articles in Medicine and Health Sciences
Modelling Plant Species Distribution In Alpine Grasslands Using Airborne Imaging Spectroscopy, Julien Pottier, Zbynek Malenovký, Achilleas Psomas, Lucie Homolova, Michael E. Schaepman, Philippe Choler, Wilfried Thuiller, Antoine Guisan, Niklaus E. Zimmermann
Modelling Plant Species Distribution In Alpine Grasslands Using Airborne Imaging Spectroscopy, Julien Pottier, Zbynek Malenovký, Achilleas Psomas, Lucie Homolova, Michael E. Schaepman, Philippe Choler, Wilfried Thuiller, Antoine Guisan, Niklaus E. Zimmermann
Faculty of Science, Medicine and Health - Papers: part A
Remote sensing using airborne imaging spectroscopy (AIS) is known to retrieve fundamental optical properties of ecosystems. However, the value of these properties for predicting plant species distribution remains unclear. Here, we assess whether such data can add value to topographic variables for predicting plant distributions in French and Swiss alpine grasslands. We fitted statistical models with high spectral and spatial resolution reflectance data and tested four optical indices sensitive to leaf chlorophyll content, leaf water content and leaf area index. We found moderate added-value of AIS data for predicting alpine plant species distribution. Contrary to expectations, differences between species distribution …
Minimizing Measurement Uncertainties Of Coniferous Needle-Leaf Optical Properties. Part Ii: Experimental Setup And Error Analysis, Lucia Yanez-Rausell, Zbynek Malenovsky, Jan G. P. W Clevers, Michael E. Schaepman
Minimizing Measurement Uncertainties Of Coniferous Needle-Leaf Optical Properties. Part Ii: Experimental Setup And Error Analysis, Lucia Yanez-Rausell, Zbynek Malenovsky, Jan G. P. W Clevers, Michael E. Schaepman
Faculty of Science, Medicine and Health - Papers: part A
We present uncertainties associated with the measurement of coniferous needle-leaf optical properties (OPs) with an integrating sphere using an optimized gap-fraction (GF) correction method, where GF refers to the air gaps appearing between the needles of a measured sample. We used an optically stable artificial material simulating needle leaves to investigate the potential effects of: 1) the sample holder carrying the needles during measurements and 2) multiple scattering in between the measured needles. Our optimization of integrating sphere port configurations using the sample holder showed an underestimation of the needle transmittance signal of at least 2% in flat needles and …
Minimizing Measurement Uncertainties Of Coniferous Needle-Leaf Optical Properties, Part I: Methodological Review, Lucia Yanez-Rausell, Michael E. Schaepman, Jan G. P. W Clevers, Zbynek Malenovsky
Minimizing Measurement Uncertainties Of Coniferous Needle-Leaf Optical Properties, Part I: Methodological Review, Lucia Yanez-Rausell, Michael E. Schaepman, Jan G. P. W Clevers, Zbynek Malenovsky
Faculty of Science, Medicine and Health - Papers: part A
Optical properties (OPs) of non-flat narrow plant leaves, i.e., coniferous needles, are extensively used by the remote sensing community, in particular for calibration and validation of radiative transfer models at leaf and canopy level. Optical measurements of such small living elements are, however, a technical challenge and only few studies attempted so far to investigate and quantify related measurement errors. In this paper we review current methods and developments measuring optical properties of narrow leaves. We discuss measurement shortcomings and knowledge gaps related to a particular case of non-flat nonbifacial coniferous needle leaves, e.g., needles of Norway spruce (Picea abies …