A focused activity of the CEOS WGCV Land Product Validation (LPV) Subgroup
The LPV LAI Intercomparison Sites
Land Product Validation participants have recommended several activities deserving immediate attention. One prominent need is for an intercomparison of both research and operational LAI products, together with the development and assessment of standards for field measurement of LAI and the scaling of these measurements to remotely sensed imagery.
Toward this need, investigators with field measurements have agreed to share their data sets for the purpose of intercomparison. An October 2000 survey indicated that field data from at least 22 sites were available. Further, remote sensing data from at least 10 different sensors have been collected in association with these field efforts. These data will serve as the basis for the intercomparison activity. To date, most investigators worked exclusively on their own data sets.
Scroll the menu to the left for a list of LAI intercomparison sites and access to more detailed site information and available data.
LPV LAI Intercomparison Activity
- Data Access Page
Addressing this question requires a methodical, quantitative intercomparison of similar products, such as the pathfinding work by the CEOS Land Product Validation subgroup on the intercomparison of global LAI products, presented at the 2006 Global Vegetation workshop by Sebastien Garrigues. You may download Sebastien's presentation here.
A list of intercomparison sites used in the overview paper for the IEEE TGARS Special Issue on Land Product Validation, Validation of global moderate resolution LAI Products: a framework proposed within the CEOS Land Product Validation subgroup is available for view or download . A global map that includes the set of intercomparison sites is also available via the pull-down 'Sites' menu to the left. Select the 'Site'Map' item in the list (first in list) to go to the map page.
A related paper led by Frederic Baret of the INRA/France, is also included in this special issue. In this paper he proposes a network of sites dedicated to the intercomparison of land biophysical products. This network of sites, the CEOS Benchmark Land Multisite Analysis and Intercomparison of Products (BELMANIP), is a globally distributed set of sites built on existing networks such as EOS Core Sites, Bigfoot, and VALERI where direct biophysical measurements were available, FLUXNET and AERONET sites, where some ground data also existed, and finally the set was completed with additional sites selected to improve the representivity of the latitudinal distribution of domiant surface types. See the manuscript for details of the selection process. A list of the BELMANIP sites can be viewed here.
The basis for this activity was formed at an initial meeting hosted by ESA, in Frascati, Italy, in June of 2001. This meeting provided an opportunity to share insights and evaluate progress on LAI product validation and to place this work in the context of the Global Observation of Forest Cover (GOFC) program. Based on the discussion and presentations at the meeting, the LPV subgroup would like to prepare a manuscript of best-practice strategies for validating satellite-derived LAI products. Once completed, this paper will be submitted for publication in a peer-reviewed journal and made available on the LPV site.
This ESA kick-off meeting was documented in The Earth Observer article "Summary of the International Workshop on LAI Product Validation."
A follow-up LAI Intercomparison meeting was held in the summer of 2004 at the University of Montana prior the the MODIS Vegetation Workshop II (also found on the Biophysical Meetings page via the 'Biophysical' pull-down menu). See the Earth Observer summary article of the meeting in the Sept/Oct 2004 issue.