Online access to weather satellite imagery through the World Wide Web

Both Global Area Coverage (GAC, 4 km) and High Resolution Picture Transmission (HRPT, 1 km) data from the Advanced Very High Resolution Radiometer (AVHRR) are made available to Internet users through an online data access system. Created as a "testbed" data system for the National Aeronautics and Space Administration's (NASAs) future Earth Observing System Data and Information System (EOSDIS), this testbed provides an opportunity to test both the technical requirements of an online data system and the different ways in which the user community would employ such a system. Initiated in December, 1991 the basic data system experienced 5 major evolutionary changes in response to user requests. Features added with these changes were online browse, user subsetting, dynamic image processing/navigation, a stand-alone data storage system and movement from an X-windows GUI interface to a WWW interface. Over its lifetime the system has had as many as 2,500 registered users. Recent additions include a realtime 7-day, northwestern U.S. Normalized difference vegetation index (NDVI) composite, a GAC SST composite, a daily image of Colorado and an NDVI image for North America.