title: The normalised difference vegetation index obtained from agrometeorological standard radiation sensors: A comparison with ground-based multiband spectroradiometer measurements during the phenological development of an oat canopy.
abstract: Following the methodology of K. F. Huemmrich and colleagues [Huemmrich et al. (1999) J Geophys Res 104:27,935-27,944], agrometeorological standard radiation sensors, i.e. two photosynthetically active radiation sensors and an albedometer, were used to measure the broadband visible and optical-infrared reflectance of an oat plot during its whole growth period. From these reflectance data - recorded as 15-min averages and pooled to daily means - the seasonal cycle of the normalised difference vegetation index (NDVI) was calculated. In addition, a ground-based multi-channel spectroradiometer was used as a reference to estimate narrowband "green" and "red" NDVIs at weekly intervals near noon. The narrowband "green" NDVI was shown to be consistent with the simultaneous broadband 15-min NDVI. This shows that the configuration of agrometeorological radiation sensors is suitable to adequately track phenological crop dynamics.
authors.affiliation: Agrarmeteorologische Forschung, Deutscher Wetterdienst, Braunschweig, Germany. klaus-peter.wittich@dwd.de
authors.forename: Klaus-Peter
authors.initials: KP
authors.lastname: Wittich
authors.forename: Martin
authors.initials: M
authors.lastname: Kraft
mesh_terms: D000383:Agriculture / Q000295:instrumentation* / Q000379:methods; D000465:Algorithms; D018554:Avena / Q000254:growth & development*; D003627:Data Interpretation, Statistical; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007259:Infrared Rays; D008027:Light; D055904:Meteorology / Q000295:instrumentation* / Q000379:methods; D011874:Radiometry / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000295:instrumentation* / Q000379:methods