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Historical Hydrographic Data

From: “Data Base Description for the Generalized Digital Environmental Model -Variable Resolution (GDEM-V),” Version 2.1, published August 1998, Naval Oceanographic Office Systems Integration Division, Stennis Space Center, MS.

The Generalized Digital Environmental Model — Variable resolution version 2.1 from August 1998 is developed by the Naval Oceanographic Office and consists of a database of different resolutions of gridded synthetic oceanographic data.

GDEM is constructed from a set of four-dimensional steady-state digital models of ocean temperature and salinity. These models consist of gridded sets of temperature and salinity with a spatial grid resolution of 20 arc-minutes, a temporal spacing of 12 months, and 34 depths from the sea surface to the ocean bottom. The data exists in all ocean areas in water depths deeper than 100 meters.

The original source of data for the construction of these climatological models is the Master Oceanographic Observation Data Set (MOODS), which contains over 5.5 million profiles of temperature/salinity dating back to 1920. This database is maintained by NAVOCEANO and is continually updated by data from the National Oceanographic Data Center, NAVOCEANO survey assets, and restricted/classified data from other sources.