NASA established its free and open Earth science data and information policy in the early 1990s, and the Earth Observing System Data and Information System (EOSDIS) Distributed Active Archive Centers (DAACs) conform to this policy. EOSDIS data usage metrics illustrate the benefits of making NASA data openly available to the public and show a rapid growth in data distribution to a worldwide community of data users. In fact, each year since 2014 the EOSDIS has distributed over one billion data files of products from satellite, aircraft, and in situ observations.
Over the last two decades, many other organizations around the world also have adopted open data policies. NASA’s Earth Science Data and Information System (ESDIS) Project, which manages the EOSDIS data systems, participates as a member in several national and international data systems communities, all of which promote openness in data sharing.
Notable among these data system communities is the International Council for Science (ICSU) World Data System (WDS). The ICSU, which was founded in 1931 and is headquartered in Paris, France, is devoted to international cooperation in the advancement of science. The ICSU established a set of World Data Centers to archive and distribute data collected from the observational programs of the 1957-1958 International Geophysical Year. All data held in the World Data Centers were available to users for the cost of reproduction and fulfilling their requests. Over time, the World Data Centers broadened their coverage of scientific disciplines and expanded to include 52 centers in 12 countries.
In 2009, the ICSU replaced the existing, stand-alone World Data Centers with the unified World Data System (WDS). The WDS is a common globally interoperable distributed data system incorporating emerging technologies and new scientific data activities. The objectives of the WDS are to:
- Enable universal and equitable access to quality-assured scientific data, data services, products, and information;
- Ensure long-term data stewardship;
- Foster compliance to agreed-upon data standards and conventions; and
- Provide mechanisms to facilitate and improve access to data and data products.
These objectives mirror those of the EOSDIS, and the NASA Advisory Committee recommended in 2012 that the ESDIS Project and the DAACs should become members of the WDS.
There are four types of WDS membership – Regular, Network, Partner, and Associate. Of these, Regular and Network memberships are most applicable to the ESDIS Project and the DAACs. Regular Members are organizations that are data stewards and/or data analysis services. These include data centers and services that support scientific research by holding and providing data or data products (such as the EOSDIS DAACs). Network Members are umbrella bodies representing groups of data stewardship organizations and/or data analysis services (such as the ESDIS Project). As of March 21, 2018, the WDS comprises 111 worldwide member organizations, with 72 Regular Members and 11 Network Members.
Organizations become WDS members by going through a formal application process that includes submission of a letter of intent and a formal application, a response to review questions posed by the WDS Scientific Committee, and the signing of a Letter of Agreement between the applicant organization and the WDS.
An updated application process for WDS Regular Members now entails a self-evaluation through a new international organization called CoreTrustSeal. Certification under CoreTrustSeal requires organizations petitioning for WDS Regular Membership to review their end-to-end data management processes in the context of relevant international standards and best practices, a review by the CoreTrustSeal board (which includes members of the WDS Scientific Committee), certification by CoreTrustSeal, and a Letter of Agreement between the applicant organization and the WDS.
The ESDIS Project became a WDS Network Member in 2012 and is actively involved in WDS activities. In addition, 10 of the 12 EOSDIS DAACs are WDS Regular Members (the exceptions being the Physical Oceanography DAAC [PO.DAAC] and the Level 1 and Atmosphere Archive and Distribution System [LAADS] DAAC). LAADS DAAC is in the process of becoming a WDS Regular Member.
The EOSDIS DAACs also are represented on the WDS Scientific Committee. The deputy manager of the EOSDIS Socioeconomic Data and Applications Center (SEDAC), Dr. Alex de Sherbinin, has served as an elected member of the WDS Scientific Committee since 2015, a term that has been renewed in 2018. As the WDS governing body, the Scientific Committee develops and prioritizes plans for the WDS, guides the implementation of these plans, and publicizes the results.
Membership in the WDS provides numerous benefits for member organizations, many of which complement EOSDIS goals and objectives. These general member benefits and their application to the EOSDIS and the DAACs include:
- Demonstrated commitment to open science – Since its establishment in 1958, NASA has been a pioneer in its commitment to open science. This commitment is clearly stated in the agency’s free and open data and information policy for Earth science that has existed since the beginning of the Earth Observing System (EOS) Program in 1990. This is commensurate with the WDS Data Sharing Principles. Continuing to affirm this commitment through recognized international scientific organizations such as the WDS provides assurance to the worldwide scientific community that NASA remains fully committed to open data sharing, even when governments may place restrictions on direct bilateral scientific interactions. Further, this commitment affords the EOSDIS DAACs additional opportunities to engage with other science data systems and archives outside of their current discipline-oriented connections. This could be especially beneficial to an EOSDIS that must engage in more international interactions and data reciprocity than has been done in previous decades. For newer members of the WDS, signing up to these WDS principles demonstrates their commitment to open science and offers a greater short-term benefit than it does to the EOSDIS. The WDS website publicizes its members with brief introductions and pointers to their respective websites. Additionally, obtaining certification as a trusted data repository permits members to display the WDS (or CoreTrustSeal) logo on their websites.
- Certification as a trusted digital repository – Many data users, especially in the private sector, are increasingly interested in identifying “trusted” data sources that they can depend on under emergency conditions or when legal liability may be an issue. Additionally, certification as a trusted digital repository is potentially an important factor in a decision to use or not use a particular data source. In light of the rapid increase in the variety and volume of Earth observation data from both public and private sources, the peer review process provided by the WDS CoreTrustSeal certification (and the requirement for recertification every three years) may be valuable in further assuring EOSDIS data users of the long-term integrity, quality, reliability, accessibility, transparency, and usability of EOSDIS data.
- Increased performance and agility – For organizations without the strong infrastructure enjoyed by the EOSDIS, the ability to include their data holdings in the WDS catalog is a significant benefit. For the EOSDIS, if the metadata querying interfaces between the WDS catalog and the EOSDIS Common Metadata Repository (CMR) are fully implemented, an even broader community visibility could be realized. Collaborations and exchange of information about best practices at venues such as the annual WDS and Committee on Data (CODATA) of the International Council for Science (ICSU) SciDataCon meetings as well as regular webinars hosted by the WDS are an additional benefit. These interactions enable the EOSDIS, the ESDIS Project, and member DAACs to learn about new data science and data management approaches and improve interoperability with peer data networks, centers, and services around the world. For example, the WDS and other international scientific groups are promoting data citations and the use of Digital Object Identifiers (DOIs) for data and data sets, as is the EOSDIS. These efforts are expected to facilitate a broader and more consistent use of data citations in publications and applications across disciplines as well as internationally. The WDS CoreTrustSeal certification/recertification process itself may be valuable in requiring EOSDIS DAACs to periodically review their end-to-end data management processes in the context of relevant international standards and best practices. This, in turn, should lead to improved data quality and documentation, expanded capabilities and interoperability, and increased efficiency and usability. As with other peer-review processes in science, regular peer review of data center processes and management is likely to benefit both reviewees and reviewers.
- The WDS Data Stewardship Award – Each year, the WDS solicits nominations for the organization’s Data Stewardship Award. This award highlights “exceptional contributions to the improvement of scientific data stewardship by early career researchers through their (1) engagement with the community, (2) academic achievements, and (3) innovations.” The award provides early-career staff in WDS member organizations significant visibility in the international community, and award winners are invited to present at WDS conferences and are provided travel support to attend WDS international meetings. The 2015 award recipient, Dr. Yaxing Wei, is a geospatial information scientist at the EOSDIS Oak Ridge National Laboratory (ORNL) DAAC and made a presentation to the plenary session of the WDS SciDataCon 2016 meeting in Denver, CO, USA.
- Opportunities for interaction with WDS members through international meetings – The WDS Scientific Committee organizes biennial meetings of WDS members, generally in concert with ICSU CODATA scientific conferences. These meetings provide an opportunity to interact and exchange ideas with data managers from around the world and cover a wide variety of scientific disciplines. The ESDIS Project and EOSDIS DAACs have participated in these conferences since 2014. The next WDS members’ meeting will be held in conjunction with International Data Week (November 5-8, 2018), and takes place in Gaborone, Botswana.
As an early adopter of a free and open data policy, NASA’s Earth Science Data System (ESDS) Program, including the EOSDIS, the ESDIS Project, and the individual EOSDIS DAACs, shares a common set of objectives with the WDS. Through its active participation on the WDS Scientific Committee and in WDS initiatives, the EOSDIS and the DAACs are helping ensure not only the proper archiving of Earth science data, but also fostering sound data management strategies. The result is better Earth science data that are scientifically reliable and more easily available to an ever-growing worldwide data user community.