Matching the phenology of net ecosystem exchange and vegetation indices estimated with MODIS and FLUXNET in-situ observations
Balzarolo, Manuela (Universiteit Antwerpen. Departement Biologie)
Vicca, Sara (Universiteit Antwerpen. Departement Biologie)
Nguy-Robertsonb, A. L. (University of Nebraska-Lincoln. School of Natural Resource Sciences)
Bonal, Damien (Institut National de la Recherche Agronomique (França))
Elbers, J. A. (Alterra (Organization : Netherlands))
Fu, Y. H. (Universiteit Antwerpen. Departement Biologie)
Grünwald, Thomas (Technische Universität Dresden. Institut für Hydrologie und Meteorologie)
Horemans, Joanna A. (Universiteit Antwerpen. Departement Biologie)
Papale, D. (Università degli studi della Tuscia. Dipartimento per l'Innovazione dei sistemi biologici, agroalimentari e forestali)
Peñuelas, Josep (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Suyker, A. (University of Nebraska-Lincoln. School of Natural Resource Sciences)
Veroustraetej, F. (Universiteit Antwerpen. Department of Bioscience Technik)

Date:	2016
Abstract:	Shifts in ecosystem phenology play an important role in the definition of inter-annual variability of net ecosystem carbon uptake. A good estimate at the global scale of ecosystem phenology, mainly that of photosynthesis or gross primary productivity (GPP), may be provided by vegetation indices derived from MODIS satellite image data. However, the relationship between the start date of a growing (or greening) season (SGS) when derived from different vegetation indices (VI's), and the starting day of carbon uptake is not well elucidated. Additionally, the validation of existing phenology data with in-situ measurements is largely missing. We have investigated the possibility to use different VI's to predict the starting day of the growing season for 28 FLUXNET sites as well as MODIS data. This analysis included main plant functional types (PFT's). Of all VI's taken into account in this paper, the NDVI (Normalized Difference Vegetation Index) shows the highest correlation coefficient for the relationship between the starting day of the growing season as observed with MODIS and in-situ observations. However, MODIS observations elicit a 20-21 days earlier SGS date compared to in-situ observations. The prediction for the NEE start of the growing season diverges when using different VI's, and seems to depend on the amplitude for carbon and VI and on PFT. The optimal VI for estimation of a SGS date was PFT-specific - for example the WRDVI for cropland, but the MODIS NDVI performed best when applied as an estimator for Net Ecosystem Exchange and when considering all PFT's pooled.
Grants:	European Commission 610028
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Vegetation indices (VI's) ; Net Ecosystem Exchange (NEE) ; Start of net carbon uptake (SGSNEE) ; Start of growing season (SGS) ; Plant functional types (PFT's) ; Phenology
Published in:	Remote sensing of environment, Vol. 174 (March 2016) , p. 290-300, ISSN 0034-4257

DOI: 10.1016/j.rse.2015.12.017

Post-print 53 p, 1.4 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > CREAF (Centre de Recerca Ecològica i d'Aplicacions Forestals) > Imbalance-P
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