The Global Change Master Directory: Connecting Users of Climate Data with Producers of Climate Data

Presently, the Internet provides access to thousands of climate related data sets. However, because conventional search engines reference millions of World Wide Web documents, locating a specific data set is challenging. The Global Change Master (GCMD), http://gcmd.nasa.gov, is a project funded by NASA that is designed to assist scientists in locating Earth Science data sets. The GCMD is a free on-line service providing over 8500 data set descriptions of atmospheric, oceanographic, geologic, geographic, ecological, and socioeconomic data holdings from around the world. In order to search the data set descriptions, the user may apply two principal search tools. The Science Keyword Search interface allows the user to search via a set of controlled vocabulary words that are hierarchically arranged. Searches may then be further refined by Location, Platform, Sensor, and Project. The Free-Text Search interface resembles the conventional search engine in that the user can perform a search using any word or phrase. Data holders are encouraged to register their data with the GCMD using on-line metadata writing tools. Data set descriptions from recent NASA missions including TERRA, TRMM, and LANDSAT-7 are currently available. The GCMD Home Page also features links to over 1200 Earth Science servers, a global change conference calendar, and a global environmental change learning center. The GCMD is the American coordinating node of the Committee on Earth Observation Satellites (CEOS) International Directory Network (IDN).