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Alan Mark Dwyer, Hughes STX

Richard A. Bolton, Office of Satellite Data Processing and Distribution, NOAA/NESDIS

Users around the world are now able to access data easily from NOAA's polar-orbiting satellites via NOAA's new Satellite Active Archive (SAA). The SAA system enables users on the Internet to quickly search, browse, order, and receive satellite data. The data can be delivered over the network or be mailed to users on various media. Initially, AVHRR (Advanced Very High Resolution Radiometer) data are available via SAA (Table 1). In coming months, additional satellite and ground truth data will become available through the SAA.

Although users can interact with the SAA through an ASCII interface, an X Windows interface is necessary to use SAA's full functionality. SAA is based on client/server technology, resides on a cluster of IBM RS/6000 workstations, and uses the UNIX/AIX operating system and Informix DBMS. StorageTek 4400 and IBM 3495 robotic mass storage systems are connected by fiber optics to NOAA's primary satellite product generation system, CEMSCS (Central Environmental Satellite Computer System), for the primary storage of up to 7 terabytes of near online data.

The SAA is also a node on the World Wide Web (WWW) on the Internet. Mosaic client software developed by the National Center for Supercomputing Applications is an effective tool for navigating the Internet and accessing the ever-expanding universe of WWW hypertext and hypermedia information resources. WWW users will be able to access the SAA from the SAA home page and thereby greatly increase the number of its potential users. SAA will also be accessible from the NESDIS and OSDPD home pages.

The development and management of the SAA is being led by the Office of Satellite Data Processing and Distribution (OSDPD) within the NOAA National Environmental Satellite, Data, and Information Service (NESDIS). User assistance and data order distribution functions are supported by the Satellite Data Services Division of NOAA's National Climatic Data Center (NCDC). NCDC's accounting system is also being integrated into SAA to provide a robust user registration and accounting capability. Development of the SAA has also been coordinated with the NCDC, the National Geophysical Data Center (NGDC), the National Oceanographic Data Center (NODC), and NASA's EOSDIS program.

One of the methods by which NOAA, NASA, and other partners in the U.S. Global Change Research Program are addressing the need to gain a greater understanding of the planet Earth is by participating in the Earth Observing System (EOS) program. Interoperability between the SAA and EOSDIS will enable NESDIS to make its data - continued on page 12

To provide Internet users with ready access to its data and information resources, the National Geophysical Data Center has created GOLD, the Geophysical OnLine Data system. The purpose of GOLD is to facilitate dissemination of data, metadata, and information to customers on the Internet via Mosaic (http://www.ngdc.noaa.gov/), Gopher (gopher.ngdc.noaa.gov), and anonymous FTP (ftp.ngdc.noaa.gov).

NGDC manages environmental data in the fields of solar-terrestrial physics, solid earth geophysics, marine geology and geophysics, paleoclimatology, and glaciology (snow and ice). In each of these fields, it also operates discipline centers of World Data Center A. In addition, NGDC maintains the Defense Meteorological Satellite Program Data Archive and integrates global ecological and environmental data.

NGDC has long served its customers via the Internet, installing anonymous FTP services for colleagues and customers in 1986. In the past few years, NGDC has increased its commitment to providing Internet services. In December 1992, NGDC implemented the Washington University (St. Louis) version of anonymous FTP, which provides user authentication, automatic compression and "tar"-ing of files, and expanded accounting capabilities. Over the last year, GOLD/anonymous FTP customer usage, as measured in host accesses, has increased 1200 percent.

In October 1993, the NGDC announced its Gopher services, providing a graphical, menu-driven interface to the Center's anonymous FTP system. Although Gopher is much easier to use than anonymous FTP, NGDC has seen a steady increase in usage of both services. Over the last six months, GOLD/Gopher usage-measured in host-accesses-has increased 400 percent.

Continuing to build momentum, on February 5, 1994, the NGDC announced its World Wide Web (WWW) server, providing some of the first Mosaic access to information and data in NOAA. As part of the NGDC's strategy of complementary GOLD components, linkages to both NGDC's Gopher and

anonymous FTP are provided within the WWW server. In addition, there are GOLD links to other servers at NOAA headquarters, other NOAA line offices, and other sources of geophysical data within government, industry, and academia. Clearly, NGDC's GOLD is an active element in the World Wide Web. To provide the human touch to NGDC's customers, however, GOLD also provides point-of-contact information for NGDC personnel such as name, phone number, and electronic mail address. Over the last four months, GOLD/ WWW has logged an average of almost 1000 host accesses per week.

Recent GOLD/WWW efforts at NGDC have been directed towards providing interactive applications online. Current online applications include: ■Full menu-driven access to the Index to Marine Geological Samples database and NGDC's Marine Geological Digital Inventory (GEOLIN) using a fill-in, forms-based user interface with an underlying commercial, cross-platform search and retrieval library developed cooperatively by NGDC and Dataware Technologies, Inc.

■The NGDC HDF (Hierarchical Data Format) Translation Demonstration, which translates data into HDF using the FREEFORM Data Description Language and "makeHDF."

Planned GOLD/WWW interactive online applications include:

Access to metadata using the interactive, platform-independent, GeoVu compatible menu systems. ■Dynamic retrievals from point/image data sets in many formats.

On March 25, 1994, NGDC announced the creation of the "NOAAOnline" mail list, a forum for NOAA administrators of online services to exchange information quickly and consult with their peers on the issues of the World Wide Web installation, configuration, security, and innovations. To request a subscription to this list, send an electronic mail message to:

listproc@ngdc.noaa.gov

with the message body (beginning in column 1) containing the following:

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