NASA and its interagency and international partners are striving to discover patterns in climate that will allow us to predict and respond to environmental events such as floods, drought, hurricanes, wild fires, and severe winters. This requires an understanding of the land, ocean, and atmosphere, at a given time and how they interact with one another. The Earth Observing System (EOS) is targeted to retrieve data on the Greenhouse Effect, Ocean Processes, Vegetation and Hydrology Changes, Ozone Depletion, Global Ice and Sea Level Changes, Cloud Radiative Effects, and the Impact of Volcanoes, which will be utilized in discovering such climate patterns.
EOS involves a series of satellites that orbit the Earth, carrying advanced instruments that have a broad range of spatial and spectral resolutions, and operate passively or actively over the electromagnetic spectrum. This, along with aircraft and ground observing systems currently in operation, will produce datasets on global, regional, and local scales. Two EOS instruments, measuring Earth's radiation balance and lightning, were launched on the Tropical Rainfall Measuring Mission (TRMM) in November 1997. The first comprehensive EOS satellite (EOS AM-1) is scheduled for launch in 1998, with the primary focus on observing the Earth's surface, clouds, aerosols, and radiation balance. It will be followed by other satellites dedicated to other aspects of the Earth system so that there will be a minimum of 15 years of continuous Earth observation.
Key components of the EOS Data and Information System (EOSDIS) framework are the Distributed Active Archive Centers (DAACs), which have the institutional responsibility for holding the archive of data products, and for making these products easily available to anyone who wants them. Each data center specializes in a particular Earth science discipline, providing comprehensive expertise for interdisciplinary studies. These include TOPEX/Poseidon data housed at the Jet Propulsion Laboratory (JPL) DAAC clearly showing the onset of the 97-98 El Nino; the National Snow and Ice Data Center (NSIDC) DAAC monitoring of the growth and decay of ice shelves in Antarctica; and the Oak Ridge National Laboratory (ORNL) DAAC studying Net Primary Production (NPP), the flux of carbon and energy between the atmosphere and green plants, which gives an indication of the conditions of the land.
EOSDIS relies on an automated Information Management System (IMS) to help manage user discovery and distribution of its vast stores of data products. The IMS provides "one stop shopping", allowing users to search for and order data in a single session from any or all of the EOS DAACs, and/or from several collaborating U.S. agencies and international partners. This free service allows easy access to both summary and detailed data descriptions, as well as browse images and fully processed science data products. At present, EOSDIS manages a catalog of over 700 data sets, mostly free of charge. Access to data is currently available through the EOSDIS IMS, operating since August 1994 (http://eos.nasa.gov/v0ims).