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GCN Home > 05/24/04 issue

Weather agency goes first-CLASS

By Susan M. Menke, GCN Staff

One of the world’s largest stores of environmental data is now online at a dual-sited federal portal called CLASS.

The Comprehensive Large Array-data Stewardship System in March began serving up more than 41T—that’s terabytes—worth of National Oceanic and Atmospheric Administration environmental data collected from satellite and ground observations. CLASS operates out of the National Climatic Data Center in Asheville, N.C., and the Office of Satellite Data Processing and Distribution in Suitland, Md.

Each site has two dual-processor IBM p660 eServers running AIX, plus a robotic tape library, said Charles Bryant, a computer specialist at Suitland.

Both sites share the same data catalog and are synchronized in near-real time so either site can fail over to the other if necessary. The eServers communicate over a 45-Mbps T3 channel on a 155-Mbps Synchronous Optical Network OC-3 dedicated connection.

IBM Informix Dynamic Server Enterprise Edition replication keeps the two archives synchronized “within a few seconds of real time,” Bryant said.

“Browse images” of large satellite data sets, such as oceans or continents, also stay synced. At class.noaa.gov, users can search and order from 28 available types of atmospheric, coastal, ocean and other data products.

Bryant said requests are filled in minutes, hours or days depending on the size of the data sets. “We try to be flexible with our user community within the confines of our resources.”

CLASS has about 24,600 registered users—a mixture of public- and private-sector climatic researchers and weather forecasters. Eventually they will be able to order and pay for their data sets online.

Because the data sets are so large and varied, CLASS must use spatial extensions to standard relational database management system formats, NOAA IT specialist David J. Vercelli—the original CLASS program manager—told the American Meteorological Society last year.

In addition to building CLASS, NOAA is “developing tools to extract spatial information stored in the file record headers, and to ingest that data into the geospatial databases as [satellite] orbits and scan lines,” Vercelli said. Users will immediately benefit, he said, if they can make general Structured Query Language queries as well as geospatial ones.

By fiscal 2011, NOAA will have spent $117 million on CLASS development, compared with “an estimated cost of $212 million to maintain the status quo” of data dissemination, agency spokesman John Leslie said.

The 10-year total cost to operate individual archive systems would have been more than $400 million, compared with $180 million for CLASS, Leslie said.

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