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World Data Centers

Prepared from publications of the World Data Centers with additional input from the National Academy of Sciences. The WDC system includes components in the An Introduction

The World Data Centers (WDCs) were established in 1957 to provide archives for the data gathered during the International Geophysical Year (IGY). Initially, the academies of science participating in the IGY established WDCs for one or more IGY disciplines, operated them at their own expense in accord with the principles laid down by the Comite Special de I'Annee Geophysique Internationale (CSAGI), archived the IGY data specified in the IGY Guide, and served the scientific community with IGY data. In 1960, the International Council of Scientific Unions (ICSU) Comite International de Geophysique (CIG), invited the scientific community to continue to send data to the WDCs and it issued a Guide to International Data Exchange to support that purpose. Thus, the WDCs have been serving the scientific community continuously since the IGY, and many of them archive selected data from earlier periods.

Many countries offered to establish and operate WDCs, and the CSAGI decided to recognize three duplicate WDCs for each discipline to avoid data loss in case of a catastrophe at one WDC and to make data exchange more convenient for data suppliers and data users. The academies of sciences of the USA and the USSR each offered to establish WDCs for each of the IGY disciplines. These were identified as WDC-A and WDC-B, respectively. The academies of other countries offered to establish WDCs for some individual disciplines; these became known as WDC-C. In some cases, similar centers were established in Western Europe (designated WDC-C1) and in Asia and Australia (designated WDC-C2). Thus some disciplines (e.g., Ionosphere and Geomagnetism) had four duplicate WDCs while others (e.g., Oceanogaphy) had only two.

To meet scientific and economic excigencies, the Guide for data exchange was revised repeatedly by the relevant ICSU bodies with advice from data suppliers and data users. Since 1968, the WDC system has been guided and coordinated by the ICSU Panel on WDCs, made up of representatives from the ICSU organizations concerned and from the WDCs themselves. The Panel oversees the revisions to the Guide and the establishment of new WDCs or international progams. It sponsors open meetings on data-exchange matters, recognizes changes in the roster of WDCs, and facilitates the transfer of archives among WDCs.

The effectiveness of the WDC system has been enhanced by the interaction among the personnel of the WDCs through visits of WDC leaders to other centers, through interactions at international scientific meetings, and through formal working visits of WDC personnel to another WDC. The last have been especially valuable because they involve working-level staff and include hands-on treatment of data.

Another positive feature of the WDC system has been the production in several disciplines of joint catalogs of available data. These compilations have been greatly assisted by electronic communications among the centers, and the ICSU Panel on WDCs has encouraged further joint catalog production.

Changes Since the International Geophysical Year

Over the years, the list of World Data Centers (WDCs) and their functions have changed somewhat. Many of the features of the original WDC system set up during the International Geophysical Year (IGY) are still useful, while some are no longer necessary. For example, the need to duplicate all data sets at different WDCs is obsolete. Communication between WDCs is now fast and effective, and good user services can be provided if catalogs are exchanged regularly. On the other hand, having more than one WDC for a discipline still gives some security against catastrophic loss, and is convenient for both users and suppliers.

For highly specialized data sets, however, centralization in a WDC is not always practicable. Generally, the WDCs should know where these data are located, and act as referral rather than archival centers. Maintaining a large number of separate WDCs has not proved economical. Some of the centers established during the IGY could not accept the long-term commitment and the larger data sets of the post-IGY era. They have either closed or been consolidated into larger centers. Now the day-to-day management of WDCs is usually in the hands of professional data managers, while the overall direction is retained by a scientist active in some of the WDC's disciplines.

Principles of Operation

WDCs now operate under the auspices of the International Council of Scientific Unions (ICSU) for the benefit of the international scientific community and provide a mechanism for international exchange of data in all disciplines related to the Earth, its environment, and the Sun.

An individual WDC may treat one or several of the disciplines or programs covered in the Guide to the World Data Center System. The host country or institution agrees to provide the resources required for the activities of a WDC on a long-term basis. The coordination of WDC activities within a country is the responsibility of the appropriate national committee or scientific institution under which it is established. Institutions are designated as WDCs by the host country with the approval of the ICSU Panel. A WDC that is unable to continue its activities and services is expected to make its holdings and records available to another WDC in the same discipline.

Responsibilities of WDCs

WDCs exchange data among themselves (without charge, when possible). The provision of WDC data to an individual scientist or institution will normally require a charge to cover the costs of duplication and handling. A WDC may also help a scientist to obtain data not explicitly described in the Guide to the World Data Center System.

Each WDC must be open to visitors and guest workers from any country, and all data held under WDC auspices must be accessible to such visitors and workers. Each WDC has a responsibility to make available to other WDCs and the scientific community a detailed description of the data available through the WDC.

Where a WDC maintains a data collection, it must provide proper facilities for data storage and maintenance and ensure that data copies are subject to adequate standards of accuracy, clarity, and durability. WDCs explore the use of modern technology for data storage, data communications, and user access. Where more than one WDC holds or has access to data in a given discipline, joint data catalogs or inventories are compiled. WDCs coordinate their activities, standardize data formats, and cooperate in international projects.

Although WDCs make every attempt to assure reasonable standards of data quality and related documentation, the ultimate responsibility for data reliability lies with the data contributor.

Contribution of Data

World Data Centers (WDCs) receive data from individual scientists, projects, institutions, local and national data centers, and other WDCs as a result of (1) statements or recommendations of international scientific organizations, (2) data management plans of major international projects, or (3) voluntary data contributions made by agreement with a WDC.

Contributors are expected to provide relevant data to the WDCs in a specified format, with full documentation, and in accord with a prearranged schedule. The contributor is expected to pay careful attention to the quality control of the data. WDCs do not pay for data supplied but may offer other data or services in exchange.

Once data are received, the WDCs are responsible for their assimilation, compilation, inventory preparation, archiving, retrieval, and dissemination.

Exchange of Data among the WDCs

Maintaining duplicate collections of all data in WDCs A, B, C, and D is not always feasible. Rather, data in certain limited fields are routinely exchanged when usage justifies the costs of duplication. Data are provided upon request from one WDC to another, and the preparation of joint catalogs that list the holdings of all WDCs in a particular discipline is encouraged.

The WDCs have thus evolved into an integrated system. Data held in any WDC are, in principle, available to any other WDC. Centers taking part in international geophysical experiments receive various data sets collected during those experiments from other centers on request usually without charge. The exchange between centers of other types of data sets must be seen as mutually beneficial, and so requests for unusually large transfers may have to bear a charge.

Data Dissemination

A scientist who needs data should contact a WDC in the appropriate discipline by letter, telex, electronic mail, telephone, or personal visit. If the data requested are held at that WDC, they can normally be provided immediately. If, as is often the case, the data are held in another country, the WDC may communicate the request to another WDC. If the second center is able to obtain the data, they will be forwarded to the originating center and then to the user. If they are not held in the WDC system, the center may refer the requester to other sources where the data might be obtained.

WDCs may recover from users the cost of copying and transmitting data. Additional costs may arise when special services are required or when data are acquired from outside the WDC system. WDCs commonly provide services at no charge to scientists or institutions that provide data to the WDC.

Other Activities

Some centers have unique scientific experience and technical competence for performing special data-processing services. For example, because the systematic derivation of the auroral electrojet magnetic index requires laborious magnetogram digitization and extensive computation, it is calculated at WDC-C2 at Kyoto, which also derives the Dst storm-time index.

Publications are issued jointly by one or more WDCs, often in cooperation with sources of the data.

And most WDCs have programs for maintaining effective contact with the user community. Some WDCs have guest-scientist programs providing extended stays that allow a visitor to use data and interact with staff, and many conduct workshops to discuss data issues in a particular discipline or to analyze a specific data set.