Best Practice for Creating Model Metadata

Overview of the Global Change Master Directory (GCMD)

From the GCMD website (http://gcmd.nasa.gov): 

Mission

The mission of the Global Change Master Directory (GCMD) is to enable the scientific community to discover and access Earth science data and services through distributed, integrated information technology systems. The GCMD offers authoring tools to achieve this mission, which conform to international standards. Tools are available to write, directly submit, and directly update metadata records.
http://gcmd.nasa.gov/Aboutus/mission.html

The Global Change Master Directory is an extensive directory of descriptive and locational information about data sets and services relevant to global change research. At present in the GCMD database there are over 19,000 of these metadata descriptions of datasets and data services from over 1200 government agencies, research institutions, archives and universities worldwide.

The GCMD has made it very easy for the public to locate the data sets they desire. All the metadata are stored in a relational database that is accessed via several search interfaces. Searching the GCMD is completely free and requires no user registration.

• Search the GCMD using Earth science keywords. Search results can be modified by geographic location, platform/source, or instrument. Or try the map/date combo data search.

• The Full-Text Search allows a query on user specified keywords. This can be of use when searching for metadata on specific topics (e.g., El Niño or Global Warming).

What are GCMD Portals?

GCMD has recognized the importance of customization for partner organizations and is generating subset views of the GCMD directory through portals. Portals have made it easier for organizations to maintain and document their data in one place without duplicating the effort to create another online directory.

Using a portal to search a virtual subset is advantageous in that as metadata is added to the subset, it is also freely available from the GCMD general search pages for scientists in other disciplines to access and use. Usage statistics are also regularly tracked and available. Several portals are already in use (see GCMD Portals ). Currently free-text and/or a keyword interface are offered.

Why add a dataset or data service description to the GCMD?

If you have a data set or service that is relevant to global change, consider advertising to the scientific community through the GCMD. The GCMD is not limited to governmental datasets nor is it restricted to freely distributed data. It is open to anyone having data or services that may advance our understanding of Earth and its systems, from the smallest, micro-scale dataset to the largest global satellite downloads. All are welcome.

In addition, you as the data holder both maintain control of the data and its distribution (the GCMD is a data locator) as well as receive credit for the data. For holders of a great deal of data or services, the GCMD is a convenient way to maintain a descriptive index of your data or service for your own reference as well. Best of all, both searching for and including dataset and service descriptions is completely free.

GCMD contains two types of metadata records:

1. a DIF (Directory Interchange Format) describes data / data products such as model output;

2. a SERF (Service Entry Resource Format) describes a data service such as a model.

Creating a DIF:

1. Check out the DIF Writer's Guide or go directly to the

2. DIF online authoring tool

3. To automatically include record in the GoMODP portal, select “Gulf of Maine” for a Location Name and “Gulf of Maine Ocean Data Partnership” as a Project.
   note: more than one Location and Project can be added

Creating a SERF:

1. Check out the SERF Writer's Guide or go directly to the

2. SERF online authoring tool

3. To automatically include record in the GoMODP portal, select “Gulf of Maine” for a Location Name and “Gulf of Maine Ocean Data Partnership” as a Project.
   note: more than one Location and Project can be added

Examples of DIF records for Model Output:

• Princeton ocean model (POM)

• Massachusetts Bay Circulation and Effluent Modeling

• Global ocean model (OCCAM)

Examples of SERF records for Models:

• The GFDL Modular Ocean Model (MOM4)

• HYbrid Coordinate Ocean Model (HYCOM)

Additional Resources

• GoMODP Technical Guidance for Data Sharing: Check out the section, "Data Discovery – Constructing and Registering Metadata."

• Melanie Meaux at GCMD (Melanie.F.Meaux@nasa.gov)

• Nick Wolff (nwolff@usm.maine.edu)