Naval Research Laboratory

Oceanography Division
Ocean Dynamics and Prediction Branch

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NRL DBDB2

Global 2-Minute Topography

DBDB2 v2.0

            The Naval Research Laboratory Digital Bathymetry Data Base 2-minute resolution (NRL DBDB2) is a global topography data set on a 2-min by 2-min uniform grid developed for the ocean model.
            The NRL DBDB2 is based on the Navval Oceanographic Office (NAVO) global 5-min DBDBV/DBDB5 bathymetry and includes all the DBDBV high resolution data. Other high resolution bathymetry data sets such as IBCAO (Artic), DAMEE (Atlantic), MMS GOM01 (GOM), NAVO NGLI (NGOM), Choi's (JES/YES) and GA ABTG (Australia), are also incorporated. The Smith & Sandwell (1997) global seafloor topography from satellite altimetry and ship depth soundings was used for the deep water. The finest GMT (The Generic Mapping Tools) vector coastline data are applied to generate the land-sea mask. The GMT coastline data are a processed mix of the CIA's global coastline and the WVS (World Vector Shoreline) global coastline.
            To map the bathymetry data onto NRL DBDB2 grid two schemes have been applied. For those data which have lower than or compatible to 2-min resolution, a cub-spline method (Akima, 1970) was used. And for those data with a higher than 2-min resolution, a weighted average with a 2D Gaussian weighting function was applied. A creeping scheme is used to merge the bathymetry data sets. (see a 3D topography)
            The global land elevation data from NOAA NGDC GLOBE (based on USGS GTOPO30) was used on land.

DBDB2 v3.0

1. Below 60S the SCAR (Scientific Committee on Antarctic Research) coastline data are used to generate the land-sea mask. The GMT coastline used in the DBDB2 v2.0 in general following the ice edge.
2. The irregularities in the GA ABTG (Australia) were removed.
3. The mismatch on the northwestern shelf of the Sea of Okhotsk was removed by removing IBCAO data in SOK.
4. An 1-min NCOR topography data set covering the Luzon Strait at the West Pacific was added.
5. The USGS GTOPO30 30-sec land elevation data replaced the NOAA GLOBE data on the land. (An irregularities in the GLOBE)

DBDB2 v4.0

1. Assimilated sounding data from NGDC and NGA. (See improvments in Taiwan Strait, Suda Shelf and Bahama Banks)
2. Added topography for Caspian Sea from Caspian Environment Programme.

Data Sets

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