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 25,000 of these metadata descriptions of datasets and data services from over 1200 government agencies, research institutions, archives and universities worldwide.

What scientific disciplines are included in the GCMD?
The GCMD contains descriptions of data sets covering all disciplines that produce and use data to help us understand our changing planet. The GCMD includes metadata from disciplines including atmospheric science, biology, oceanography, ecology, geology, hydrology, and human dimensions of climate change. This interdisciplinary focus is aimed at researchers exploring the interconnections and interrelations of mulitdisciplinary variables on global changes (e.g., How global warming may impact human health).

How to use the GCMD?
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).

How to 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.

Are you still unsure? Take a look at some common misconceptions about the GCMD.

Go to the GCMD Home Page to try it out.

If you still have questions, send an e-mail to the GCMD staff at: gcmduso@gcmd.nasa.gov
Thanks!