The OLIVE kernel is the MVCC (Matlab Validation Core Code) which is designed to evaluate and compare land products (LAI, FAPAR, FCOVER) derived from medium resolution sensors.It follows the standards defined by the CEOS (Committee on Earth Observation Satellites)-LPV (Land Product Validation) subgroup described in Weiss et al, 2007 and Garrigues et al, 2008. It relies on the use of two independent datasets (BELMANIP2 and DIRECT). Land products are derived from medium resolution sensors. BELMANIP2 and DIRECT sites correspond to extracts of 49x49 pixels of the different product at the dates they are available.
Comparisons are then performed by providing statistics on the product, drawing histograms, scatterplots,….The MVCC generates an html report including the validation exercise characteristics and the associated results (figures and tables)
compiled in an HTML report:

1. Evaluation of the product continuity
       a. Fraction of valid data for the considered period and products at the site, continental, biome type and global levels.
     b. statistical distribution of gaps (fraction of invalid data) as a function of QA levels
     c. Spatio-temporal distribution (function of latitude and months) for the QA threshold specified   in the validation exercise
     d. Statistical distribution of the Length of Gaps (LoG),
Verger al  2008
2. Evaluation of the product temporal consistency (temporal smoothness) Weiss et al 2007
3. Generation of the temporal profiles over the period of interest
4. Evaluation of the temporal stability (spatial and spatio-temporal product climatologies)
5. Evaluation of the product statistical distribution per biome or per continent, as well as the global scale
6. Comparison with other similar products: generation of the scatterplots and associated statistics between pairs of products per biome and per continent (as well as the global scale)
7. Accuracy assessment: comparison against ground measurements

 

REFERENCES

A full description of the MVCC functionalities, inputs and outputs is available here. Further, the OLIVE paper is published in open access since May 2014: 

Weiss, M.; Baret, F.; Block, T.; Koetz, B.; Burini, A.; Scholze, B.; Lecharpentier, P.; Brockmann, C.; Fernandes, R.; Plummer, S.; Myneni, R.; Gobron, N.; Nightingale, J.; Schaepman-Strub, G.; Camacho, F.; Sanchez-Azofeifa, A. On Line Validation Exercise (OLIVE): A Web Based Service for the Validation of Medium Resolution Land Products. Application to FAPAR Products. Remote Sens. 20146, 4190-4216. URL

 

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. and Yang, W., 2008. Validation and intercomparison of global Leaf Area Index products derived from remote sensing data. J. Geophys. Res., 113, G02028: doi:10.1029/2007JG000635
 

Verger, A., Baret, F. and Weiss, M., 2008. Performances of neural networks for deriving LAI estimates from existing CYCLOPES and MODIS products. Remote Sensing of Environment, 112(6): 2789-2803.[http://www.sciencedirect.com/science/article/B6V6V-4S02TFK-3/1/b6764429074052edc88cbc88af6d42b2 ]
 

Weiss, M., Baret, F., Garrigues, S. and Lacaze, R., 2007. LAI and fAPAR CYCLOPES global products derived from VEGETATION. Part 2: validation and comparison with MODIS collection 4 products. Remote Sensing of Environment, 110(3): 317-331.[http://www.sciencedirect.com/science/article/B6V6V-4NKB1YP-1/2/7fc55dac10c40359f085241851a6fa37 ]