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The Committee on Earth Observation Satellites (CEOS), defines validation as the process of assessing, by independent means, the quality of the data products derived from the system outputs.

The MODIS Land Validation Strategy

MODIS Land (MODLAND) product quality is ensured by Calibration, Quality Assurance (QA) and Validation.  The MODIS land validation effort will contribute to and leverage off of international validation activities, helping to establish standards and protocols through close coordination with the CEOS Land Product Validation (LPV) subgroup, under its Working Group on Calibration and Validation ( WGCV).

MODLAND uses several validation techniques to develop uncertainty information for its products. These include comparisons with in situ data collected over a distributed set of validation test sites, comparisons with data and products from other sensors (e.g., ASTER, AVHRR, MISR, TM/ETM+), intercomparison of trends derived from independently-obtained reference data, and analysis of process model results.

MODLAND's primary validation technique includes the collection of field and aircraft data, and comparison with these and with products from other satellites.  The infrastructure for these efforts has resulted in the establishment of a semi-permanent array of EOS Land Validation image of Core Sites button,  most of which include a flux tower for extended temporal measurement of terrestrial biophysical dynamics over a range of landcover types.  Field data are archived in cooperation with the Oak Ridge DAAC's Mercury system.  Results of all validation activities are conveyed to the end-user through both published literature and the MODLAND product image of Val Status button pages.


Validation Hierarchy (updated Sept 2009)

  • Stage 1 Validation:  Product accuracy has been estimated using a small number of independent measurements obtained from selected locations and time periods and ground-truth/field program efforts.
  • Stage 2 Validation: Product accuracy is estimated over a significant set of locations and time periods by comparison with reference in situ or other suitable reference data.
    Spatial and temporal consistency of the product and with similar products has been evaluated over globally representative locations and time periods.
    Results are published in the peer-reviewed literature.
  • Stage 3 Validation: Uncertainties in the product and its associated structure are well quantified from comparison with reference in situ or other suitable reference data. Uncertainties are characterized in a statistically rigorous way over multiple locations and time periods representing global conditions.
    Spatial and temporal consistency of the product and with similar products has been evaluated over globally representative locations and periods.
    Results are published in the peer-reviewed literature.
  • Stage 4 Validation: Validation results for stage 3 are systematically updated when new product versions are released and as the time-series expands.

More on validation ...

   Announcements:


  • MODIS Science Team meeting, April 29 - May 1, 2014, Sheraton Columbia Town Center Hotel, Columbia, MD. Register here by April 22.
  • GV2M: Global Vegetation Monitoring and Modelling, 3rd - 7th February 2014, Palais des Papes, Avignon, France. Abstracts due October 21st.
  • Land Product Validation & Evolution workshop, January 28-30, 2014, Frascati (Rome), Italy. The abstract submission deadline is 30 September 2013.
  • MODIS Science Team meeting, April 15-17, 2013, Silver Spring Civic Building at Veterans Plaza. Register here.
  • Envisat-MERIS 10-Daily composite (EM10) data available, free download via the VITO website, 2010 through March 2012, back dates being processed.
  • MODIS Science Team Meeting, May 7-9, 2012, Silver Spring Civic Building at Veterans Plaza.
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Curator: Jaime Nickeson
NASA Official: Robert Wolfe
Last Updated: May 22, 2014

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