A Fiducial site is a geographic location that is used as a benchmark for the long-term monitoring of processes, both natural and anthropogenic, associated with the causes and effects of global environmental change. The word fiducial carries multiple meanings with regard to the GFL. Fiducials are marks or points of reference applied to images to present a fixed standard of reference, so in the GFL they refer to the identification of a place on the Earth. The term fiducial may also be interpreted to refer to a long-term trust, where one may be holding something in trust for another. Both references aptly apply, as the GFL maintains a long-term record of data over specific places on the Earth to be available for scientific investigations. Fiducial sites are associated with Earth processes and environmentally sensitive areas that are being monitored so that scientists can better understand and model the dynamic systems and changes that are occurring. The sites are located around the globe and are distributed among environmental topics and processes within five major disciplines: Ocean Processes; Ice and Snow Dynamics; Atmospheric Processes; Land Use/Land Cover; and Geologic Processes.

The data are organized by geographic region and image release date. Start by selecting a geographic region from the home page links:


Each geographic location page will contain a drop-down list on the top-right that contains all the sites available in that region. Just below the drop-down list of GFL sites, is a site description with a link to a data image gallery. When you select a GFL site from the list, the description block will jump to the site description of the selected site. The map on the left will highlight in red the point location of the site selected.

Click on the 'View and Download Data' link for the selected site. A thumbnail image gallery will open. All images are organized by the year they were collected. Click on any thumbnail to enlarge and access the download links. Click on the right and left arrows on the enlarged thumbnail to move through the available images.

Each of the GFL images in the gallery are available in two different formats, a GeoTIFF (..tif.zip) and a GeoPDF (..pdf.zip). In addition, to these actual data files, a metadata file is also available for each image (.xml). All three files are available for download for each GFL image.

Use the 'Help' link on any image gallery to get detailed information on each file available for download.