| Titre | Validation and intercomparison of global Leaf Area Index products derived from remote sensing data |
| Auteur | Garrigues, S; Lacaze, R; Baret, F; Morisette, J T; Weiss, M; Nickeson, J E; Fernandes, R; Plummer, S; Shabanov, N V; Myneni, R B; Knyazikhin, Y; Yang, W |
| Source | Journal of Geophysical Research, Biogeosciences vol. 113, no. 2, G02028, 2008., https://doi.org/10.1029/2007JG000635 (Accès ouvert) |
| Année | 2008 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20181084 |
| Éditeur | Wiley-Blackwell |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1029/2007JG000635 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Sujets | télédétection; géophysique |
| Programme | Géosciences de changements climatiques |
| Diffusé | 2008 06 11 |
| Résumé | (disponible en anglais seulement)
This study investigates the performances of four major global Leaf Area Index (LAI) products at 1/11.2° spatial sampling and a monthly time step: ECOCLIMAP
climatology, GLOBCARBON (from SPOT/VEGETATION and ATSR/ AATSR), CYCLOPES (from SPOT/VEGETATION) and MODIS Collection 4 (main algorithm, from MODIS/TERRA). These products were intercompared during the 2001-2003 period over the BELMANIP network of
sites. Their uncertainty was assessed by comparison with 56 LAI reference maps derived from ground measurements. CYCLOPES and MODIS depict realistic spatial variations at continental scale, while ECOCLIMAP poorly captures surface spatial
heterogeneity, and GLOBCARBON tends to display erratic variations. ECOCLIMAP and GLOBCARBON show the highest frequency of successful retrievals while MODIS and CYCLOPES retrievals are frequently missing in winter over northern latitudes and over the
equatorial belt. CYCLOPES and MODIS describe consistent temporal profiles over most vegetation types, while ECOCLIMAP does not show any interannual variations, and GLOBCARBON can exhibit temporal instability during the growing season over forests.
The CYCLOPES, MODIS, and GLOBCARBON LAI values agree better over croplands and grasslands than over forests, where differences in vegetation structure representation between algorithms and surface reflectance uncertainties lead to substantial
discrepancies between products. CYCLOPES does not reach high enough LAI values to properly characterize forests. In contrast, the other products have sufficient dynamic range of LAI to describe the global variability of LAI. Overall, CYCLOPES is the
most similar product to the LAI reference maps. However, more accurate ground measurements and better representation of the global and seasonal variability of vegetation are required to refine this result. |
| GEOSCAN ID | 311438 |
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