Close relationship between spectral vegetation indices and V cmax in deciduous and mixed forests

摘要: Seasonal variations of photosynthetic capacity parameters, notably the maximum carboxylation rate, V cmax , play an important role in accurate estimation CO 2 assimilation gas-exchange models. Satellite-derived normalised difference vegetation index (NDVI), enhanced (EVI) and model-data fusion can provide means to predict seasonal variation . In this study, was obtained from a process-based model inversion, based on ensemble Kalman filter (EnKF), gross primary productivity, sensible latent heat fluxes measured using eddy covariance technique at two deciduous broadleaf forest sites mixed site. Optimised showed considerable inter-annual both ecosystems. There noticeable hysteresis relation EVI NDVI 8 d composites satellite data during growing period. When period phenologically divided into phases (increasing VIs decreasing phases), significant correlations were found between VIs, mostly showing R >0.95. varied exponentially with increasing first phase VIs), but second third-order polynomials provided best fits (decreasing VIs). The relationships different. Further efforts are needed investigate –VIs more ecosystem use satellite-based for estimating Keywords: spectral indices, filter, BEPS (Published: 15 April 2014) Citation: Tellus B 2014, 66, 23279, http://dx.doi.org/10.3402/tellusb.v66.23279