Mercury, a Web-based search system at the ORNL DAAC, provides a window into land validation data from around the world. The data are primarily collected at field sites for comparison with satellite-derived products.
A total of 51 land validation data sets are currently registered in Mercury. The data include land cover, net primary productivity, leaf area index, and fluxes of carbon dioxide, water, and energy, as well as characteristics of the land validation sites. The land validation products are particularly useful for developing, calibrating, and validating ecosystem models.
Among the registered data sets are three collections of ASCII subsets derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra satellite. The three collections pertain to leaf area index and fraction of photosynthetically absorbed radiation, vegetation indices, and net photosynthesis at 25 validation sites and flux tower sites. Each subset contains 1- by 1-km pixel values representing an 8-day or 16-day composite for a 7- by 7-km area centered on a field site or flux tower. See http://public.ornl.gov/fluxnet/modis.cfm for more information about the subsets.
To search for land validation data in Mercury, visit http://mercury.ornl.gov/ornldaac/ and click on the box next to "Land Validation Data." Then select one or more search terms--textual, spatial, or temporal.
For additional land validation data archived at the ORNL DAAC, visit http://www.daac.ornl.gov, open the drop-down menu for "Available Data," and click on "Land Validation Data."