Development of these data sets is intended to provide research-quality, consistently structured time-series data sets that will be useful for global change research. This section provides summary descriptions of selected satellite image data-set collections that are likely to be of interest to researchers studying the human dimensions of global environmental change. For example, the Earth Observing System (EOS) Reference Handbook (Asrar and Dokken 1993) describes the National Aeronautics and Space Administration (NASA) Pathfinder Data Set Program, which currently includes development of six data sets, each comprising the data gathered by a different sensor. Four of the Pathfinder data sets will be primarily useful for natural science studies of the Earth's atmosphere and oceans, but the NOAA/NASA Pathfinder Advanced Very High Resolution Radiometer (AVHRR) Land Data Set and particularly the Landsat PathfinderData Set will be useful for land-related research in global change motivated by both natural science and human dimensions issues.
Much activity is also associated with the development of repetitive data sets for major land regions at 1-km spatial resolution using AVHRR data. The rationale for these data sets is provided in Advanced Very High Resolution Radiometer 1-km Land Data Sets. Significant programs include the Conterminous U.S. Advanced Very High Resolution Radiometer Data Set, the Alaska Advanced Very High Resolution Radiometer Data Set, the Tropical Resources and Environment Monitoring by Satellite Project Advanced Very High Resolution Radiometer Data Set, and the International Geosphere-Biosphere Program Global 1-Km Advanced Very High Resolution Radiometer Data Base.