TY - GEN ID - blackburn1998 AU - Blackburn, G. A. TI - Spectral indices for estimating photosynthetic pigment concentrations: A test using senescent tree leaves UR - http://dx.doi.org/10.1080/014311698215919 DO - 10.1080/014311698215919 PR - Taylor & Francis T2 - International Journal of Remote Sensing PY - 1998 DA - 1998/01/01 SN - 0143-1161 VL - 19 IS - 4 SP - 657-675 AB - Abstract The possibility of estimating the concentration of individual photosynthetic pigments within vegetation from reflectance spectra offers great promise for the use of remote sensing to assess physiological status, species type and productivity. This study evaluates a number of spectral indices for estimating pigment concentrations at the leaf scale, using samples from deciduous trees at various stages of senescence. Two new indices (PSSR and PSND) are developed which have advantages over previous techniques. The optimal individual wavebands for pigment estimation are identified empirically as 680nm for chlorophyll a, 635nm for chlorophyll b and 470nm for the carotenoids. These wavebands are justified theoretically and are shown to improve the performance of many of the spectral indices tested. Strong predictive models are demonstrated for chlorophyll a and b, but not for the carotenoids and the paper explores the reasons for this. ER - TY - JOUR ID - kooistra2003 AU - Kooistra, L. AU - Leuven, R. S. E. W. AU - Wehrens, R. AU - Nienhuis, P. H. AU - Buydens, L. M. C. TI - A comparison of methods to relate grass reflectance to soil metal contamination UR - http://dx.doi.org/10.1080/0143116031000080769 DO - 10.1080/0143116031000080769 T2 - International Journal of Remote Sensing PY - 2003 DA - 2003/01/01 SN - 0143-1161 VL - 24 IS - 24 SP - 4995-5010 AB - Grass-dominated vegetation covers large areas of the Dutch river floodplains. Remotely sensed data on the conditions under which this vegetation grows may yield information about the degree of soil contamination. This paper explores the relationship between grassland canopy reflectance and zinc (Zn) contamination in the soil under semi-field conditions. A field radiometer was used to record reflectance spectra of perennial ryegrass (Lolium perenne) in an experimental field with Zn concentrations in the soil ranging from 32 to 1800mgkg?1. Several spectral vegetation indices (VIs) and a multivariate approach using partial least squares (PLS) regression were investigated to evaluate their potential use in estimating Zn contamination levels. Compared to the best PLS model (RMSEP = 181.4 mg kg?1), the narrow band vegetation index MSAVI2mm performed better (RMSEP = 162.9 mg kg?1). Both MSAVI2mm and PLS gave a high user accuracy for the strongly contaminated soil class (100% and 91%, respectively), while the total accuracy was satisfactory (60% and 55%, respectively). Results from this feasibility study indicate the potential of using remote sensing techniques for the classification of contaminated areas in river floodplains. But as the results from this study may be both resolution- and location-dependent, research on field and image scale is now required to test the established relations and to assess their susceptibility to seasonal influences, species heterogeneity, and increased levels of spectral noise. ER - TY - JOUR ID - richardson2002 AU - Richardson, Andrew D. AU - Duigan, Shane P. AU - Berlyn, Graeme P. TI - An evaluation of noninvasive methods to estimate foliar chlorophyll content UR - http://dx.doi.org/10.1046/j.0028-646X.2001.00289.x DO - 10.1046/j.0028-646X.2001.00289.x PR - Blackwell Science Ltd T2 - New Phytologist PY - 2002 SN - 1469-8137 VL - 153 IS - 1 SP - 185-194 AB - Over the last decade, technological developments have made it possible to quickly and nondestructively assess, in situ, the chlorophyll (Chl) status of plants. We evaluated the performance of these optical methods, which are based on the absorbance or reflectance of certain wavelengths of light by intact leaves. * •As our benchmark, we used standard extraction techniques to measure Chla, Chlb, and total Chl content of paper birch (Betula papyrifera) leaves. These values were compared with the nominal Chl index values obtained with two hand-held Chl absorbance meters and several reflectance indices correlated with foliar Chl. * •The noninvasive optical methods all provided reliable estimates of relative leaf Chl. However, across the range of Chl contents studied (0.0004–0.0455 mg cm−2), some reflectance indices consistently out-performed the hand-held meters. Most importantly, the reflectance indices that performed best were not those most commonly used in the literature. * •We report equations to convert from index values to actual Chl content, but caution that differences in leaf structure may necessitate species-specific calibration equations. KW - absorbance KW - chlorophyll KW - Chla : Chlb leaf optical properties KW - pigment KW - red edge KW - reflectance KW - spectral index ER - TY - ELEC ID - idb AU - Henrich, V. AU - Krauss, G. AU - Götze, C. AU - Sandow, C. TI - The IndexDatabase UR - https://www.indexdatabase.de/ CY - Bonn PY - 2011 DA - 2011 ER -