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Focus Area on Leaf Area Index (LAI) Product Validation

Hongliang Fang, Chinese Academy of Sciences, China
Sylvain Leblanc, Natural Resources Canada


LAI Definition

Leaf area index is defined as one half the total green (i.e., photosynthetically active) leaf area per unit horizontal ground surface area.

Units: LAI is a non-dimensional quantity, although units of m2/m2 are often quoted.
This definition, based on Chen and Black (1992), was accepted by GCOS, GTOS and CEOS in 2010.

Highest Validation Stage Currently Reached for Satellite-Derived LAI Products

Validation stage 2 (LPV validation stage hierarchy) - The highest LPV validation stage reached for satellite-derived LAI products. Limitations to reach higher validation stage include limited number of validation sites, spatial and temporal gaps of in situ reference data coverage. LPV is collaborating with NEON, TERN, and ICOS to improve coverage of in situ reference data.

Validation Good Practices

The LPV Subgroup has just published a Good Practices Protocol document for validation of LAI Products. The document is available for download along with associated documents:

Fernandes, R., Plummer, S., Nightingale, J., Baret, F., Camacho, F., Fang, H., Garrigues, S., Gobron, N., Lang, M., Lacaze, R.,   LeBlanc, S., Meroni, M., Martinez, B., Nilson, T., Pinty, B., Pisek, J., Sonnentag, O., Verger, A., Welles, J., Weiss, M., &   Widlowski, J.L. (2014). Global Leaf Area Index Product Validation Good Practices. Version 2.0.  In G. Schaepman-Strub, M.   Román, & J. Nickeson (Eds.), Best Practice for Satellite-Derived Land Product Validation (p. 76): Land Product Validation   Subgroup (WGCV/CEOS), doi:10.5067/doc/ceoswgcv/lpv/lai.002
  (Download CEOS_LAI_PROTOCOL_Aug2014_v2.0.1.pdf, 5MB)

LAI Validation Reference Data Sets

Currently the best in situ reference data set for satellite-derived LAI product validation is available on the On Line Interactive Validation Exercise (OLIVE) validation platform (Weiss et al., 2014) . The objective of this platform is to provide the user community consistent and reliable information on the accuracy and associated uncertainty of EO products. Two datasets, the BELMANIP-2 and DIRECT set of sites are used within the validation exercise.


LPV Focus Areas



Recent Developments in LAI and FAPAR Estimation and Validation, July 28 - August 2, 2019 Yokohama, Japan.

EGU 2017, 23-28 April 2017, Vienna, Austria. Abstract submission due 11 Jan 2017, details here.

ESA Annouces first gathering of the Sentinel-2 Validation Team (S2VT), 8-29 November 2016, at ESRIN, Frascati, Italy.

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