GEBCO’s current gridded bathymetric data set, the GEBCO_2024 Grid, is a global terrain model for ocean and land, providing elevation data, in meters, on a 15 arc-second interval grid. It is accompanied by a Type Identifier (TID) Grid that gives information on the types of source data that the GEBCO_2024 Grid is based on.

GEBCO releases a new global grid every year, generally in late June. Find out more about the grid generation process.

The global bathymetry and topography grid at 15 Arc Sec is the latest iteration of the SRTM+ digital elevation model (DEM) where the "plus" indicates the addition of ocean bathymetry from shipboard soundings and satellite-derived predicted depths. This DEM is a global elevation grid with a spatial sampling interval of 15 arc seconds (approximately 500 x 500 m pixel size at the equator). New data consists of >33.6 million multibeam and singlebeam measurements collated by several institutions, namely, the National Geospatial-Intelligence Agency, Japan Agency for Marine-Earth Science and Technology, Geoscience Australia, Center for Coastal and Ocean Mapping, and Scripps Institution of Oceanography. New altimetry data consists of 48, 14, and 12 months of retracked range measurements from Cryosat-2, SARAL/AltiKa, and Jason-2, respectively. Onshore, topography data are sourced from previously published digital elevation models, predominately SRTM-CGIAR V4.1 between 60N and 60S. ArcticDEM is used above 60N, while Reference Elevation Model of Antarctica is used below 62S.

For more information on this dataset, see its associated publication:
Tozer, B, Sandwell, D. T., Smith, W. H. F., Olson, C., Beale, J. R., & Wessel, P. (2019). Global bathymetry and topography at 15 arc sec: SRTM15+. Earth and Space Science, 6, 1847. https://doi.org/10.1029/2019EA000658

or visit the project website here for more details.

OpenTopography enabled access to version 2.5.5 of this dataset on November 6th 2023. Previous to this date, OpenTopography was supplying V2.1

The Nippon Foundation-GEBCO Seabed 2030 project has produced a global terrain model for ocean and land. The GEBCO_2023 grid was published in April 2023 and is the fifth GEBCO grid developed through The Nippon Foundation-GEBCO Seabed 2030 Project. This is a collaborative project between the Nippon Foundation of Japan and GEBCO. The Seabed 2030 Project aims to bring together all available bathymetric data to produce the definitive map of the world ocean floor and make it available to all.

The GEBCO_2023 Grid is a continuous, global terrain model for ocean and land with a spatial resolution of 15 arc seconds. Between latitudes of 50° South and 60° North it uses version 2.5.5 of the SRTM15+ dataset as a "base". This data set is a fusion of land topography with measured and estimated seafloor topography. This version of SRTM15+ is similar to version 2.1 [Tozer et al., 2019] but includes additional data sets. It uses predicted depths based on the V32 gravity model [Sandwell et al., 2019]. The SRTM15+ base grid has been augmented with the gridded bathymetric data sets developed by the four Seabed 2030 Regional Centers to produce the GEBCO_2023 Grid. Note: SRTM15+ V2.5.5 is also available through OpenTopography here.

The information for ice-surface elevation and under-ice topography/bathymetry is taken from IceBridge BedMachine Greenland, Version 4.6 (Morlighem, M. et al. 2017) and data based on MEaSUREs BedMachine Antarctica, Version 2 (Morlighem, M. et al 2020).

NOTE: This dataset includes ice sheet topography. For a version of the dataset with under-ice topography see "GEBCO SubIceTopo" below under "Other Available Data Products".

CHS offers 500-metre bathymetric gridded data for users interested in the topography of the seafloor. This data provides seafloor depth in metres and is accessible for download as predefined areas.

Multibeam echo sounders, for Bathymetric survey, use sonar pulses to measure the distance between the survey vessel and the seabed. This instrument collects point data at a resolution of 25cm or better, depending on water depth, vessel speed and bed topography and produces a high resolution elevation dataset of the underwater terrain.

The Environment Agency's Multibeam Bathymetric data archive includes digital elevation data derived from bathymetric surveys carried out for a range of applications and locations where surveys have been previously commissioned. Multibeam data is available at 50cm resolution and supplied as an ESRI ASCII Raster which contains height, relative to Ordnance Survey Newlyn datum.

Data is available in 5km download zip files for each year of survey. Within each downloaded zip file are ASCII files aligned to the Ordinance Survey grid. The size of each tile is dependant upon the spatial resolution of the data. Elevation values are presented in metres.

Please refer to the metadata index catalgoues for the survey date captured and spatial resolution of the imagery.

A global 1-km resolution bathymetric digital elevation model (DEM) grayscale hillshade of the ocean floor. Derived from the SRTM30+ v11 dataset produced at Scripps Institution of Oceanography from United States Geological Survey (USGS) 30 arc-second SRTM30 gridded DEM data, itself a product of NASA's Shuttle Radar Topography Mission (SRTM). Bathymetry are based on the Smith and Sandwell global 1 arc-minute grid between latitudes +/- 81 degrees. Higher resolution grids have been added from the LDEO Ridge Multibeam Synthesis Project, the JAMSTEC Data Site for Research Cruises, and the NGDC Coastal Relief Model. Arctic bathymetry is from the International Bathymetric Chart of the Oceans (IBCAO). For the related dataset containing numeric bathymetry values for this image layer, see http://pacioos.org/metadata/srtm30plus_v11_bathy.html

The "EMODnet Digital Bathymetry (DTM)- 2022" is a multilayer bathymetric product for Europe’s sea and over seas basins covering: • the Greater North Sea, including the Kattegat and stretches of water such as Fair Isle, Cromarty, Forth, Forties,Dover, Wight, and Portland • the English Channel and Celtic Seas
• Western Mediterranean, the Ionian Sea and the Central Mediterranean Sea • Iberian Coast and Bay of Biscay (Atlantic Ocean) • Adriatic Sea (Mediterranean) • Aegean - Levantine Sea (Mediterranean). • Madeira and Azores (Macaronesia) • Baltic Sea • Black Sea • Norwegian and Icelandic Seas • Canary Islands (Macaronesia) • Arctic region and Barentz Sea • Caribbean Sea

The DTM is based upon 21937 bathymetric survey data sets and Composite DTMs that have been gathered from 64 data providers from 28 countries riparian to European seas and beyond. Also Satellite Derived Bathymetry data products have been included fro Landsat 8 and Sentinel satellite images. Areas not covered by observations are completed by integrating GEBCO 2022 and IBCAO V4.

The source reference layer in the portal viewing service gives metadata of the data sets used with their data providers; the metadata also acknowledges the data originators. The incorporated survey data sets itself can be discovered and requested for access through the Common Data Index (CDI) data discovery and access service that in December 2022 contained > 41.000survey data sets from European data providers for global waters. The Composite DTMs can be discovered through the Sextant Catalogue service. Both discovery services make use of SeaDataNet standards and services and have been integrated in the EMODnet portal (https://emodnet.ec.europa.eu/en/bathymetry#bathymetry-services ). In addition, the EMODnet Map Viewer (https://emodnet.ec.europa.eu/geoviewer/ ) gives users wide functionality for viewing and downloading the EMODnet digital bathymetry such as: • water depth (refering to the Lowest Astronomical Tide Datum - LAT) in gridded form on a DTM grid of 1/16 * 1/16 arc minute of longitude and latitude (ca 115 * 115 meters). • option to view depth parameters of individual DTM cells and references to source data • option to download DTM in 58 tiles in different formats: ESRI ASCII, XYZ, EMODnet CSV, NetCDF (CF), GeoTiff, TIFF and SD • option to visualize the DTM in 3D in the browser without plug-in • layer with a number of high resolution DTMs for coastal regions • layer with wrecks from the UKHO Wrecks database.

The EMODnet DTM is also available by means of OGC web services (WMS, WFS, WCS, WMTS), which are specified at the EMODnet Bathymetry portal.
The original datasets themselves are not distributed but described in the metadata services, giving clear information about the background survey data used for the DTM, their access restrictions, originators and distributors and facilitating requests by users to originator.

This part of USGS Data Series 935 (Cochrane, 2014) presents bathymetry and topography data for the Offshore of Seattle, California, map area, a part of the Southern Salish Sea Habitat Map Series. The data for this map area are a combination of topography extracted from a pre-existing Digital Elevation Model (DEM) merged with bathymetry data that were collected by the National Oceanic and Atmospheric Administration (NOAA) using multibeam sonar systems. The merged data are available for download in a single zip file (BathyTopo_OffshoreSeattle.zip).

The General Bathymetric Chart of the Oceans (GEBCO) One Minute Grid is a global terrain model for land and sea at one arc-minute intervals. The grid is largely based on the bathymetric contours contained in the Centenary Edition of the GEBCO Digital Atlas, existing grids are used in some areas. The land areas are based on the Global Land One-km Base Elevation (GLOBE) Project data set. The grid was originally released in 2003 and updated in 2008 to include data from the International Bathymetric Chart of the Arctic Ocean (IBCAO), for the region north of 64N and also updates for shallower water regions off India, the Korean Peninsula and around South Afriaca, using data extracted from Electronic Navigation Charts (ENCs). The grid is available to download, in netCDF format, for free from the internet. Free software is available for viewing and accessing data from the grid in netCDF and ASCII. This includes an option to export the grid in an ASCII form suitable for conversion to an ESRI raster. The grid is also included in the GEBCO Digital Atlas DVD. It is not intended to make any further updates to this data set. In 2009, GEBCO released a new bathymetric grid, the GEBCO_08 Grid. This is a global terrain model at 30 arc-second intervals. It is largely based on a database of ship-track soundings with interpolation between soundings guided by satellite derived-gravity data.

The "EMODnet Digital Bathymetry (DTM)- 2024" is a multilayer bathymetric product for Europe’s sea and oversea basins covering: • the Greater North Sea, including the Kattegat and stretches of water such as Fair Isle, Cromarty, Forth, Forties,Dover, Wight, and Portland • the English Channel and Celtic Seas
• Western Mediterranean, the Ionian Sea and the Central Mediterranean Sea • Iberian Coast and Bay of Biscay (Atlantic Ocean) • Adriatic Sea (Mediterranean) • Aegean - Levantine Sea (Mediterranean). • Madeira and Azores (Macaronesia) • Baltic Sea • Black Sea • Norwegian and Icelandic Seas • Canary Islands (Macaronesia) • Arctic region and Barentz Sea and the Caribbean Sea.

The DTM is based upon 22063 bathymetric survey data sets and Composite DTMs that have been gathered from 66 data providers from 28 countries riparian to European seas and beyond. Also Satellite Derived Bathymetry data products have been included from Landsat 8 and Sentinel satellite images. Areas not covered by observations are completed by integrating GEBCO 2024 and IBCAO V4.

The source reference layer in the portal viewing service gives metadata of the data sets used with their data providers; the metadata also acknowledges the data originators. The incorporated survey data sets itself can be discovered and requested for access through the Common Data Index (CDI) data discovery and access service that icontains > 41.000 survey data sets from European data providers for global waters. The Composite DTMs can be discovered through the Sextant Catalogue service. Both discovery services make use of SeaDataNet standards and services and have been integrated in the EMODnet portal (https://emodnet.ec.europa.eu/en/bathymetry#bathymetry-services ). In addition, the EMODnet Map Viewer (https://emodnet.ec.europa.eu/geoviewer/ ) gives users wide functionality for viewing and downloading the EMODnet digital bathymetry such as: • water depth (refering to the Lowest Astronomical Tide Datum - LAT) in gridded form on a DTM grid of 1/16 * 1/16 arc minute of longitude and latitude (ca 115 * 115 meters). • option to view depth parameters of individual DTM cells and references to source data • option to download DTM in 59 tiles in different formats: ESRI ASCII, XYZ, EMODnet CSV, NetCDF, GeoTiff, RGB and SD • option to visualize the DTM in 3D in the browser without plug-in • layer with a number of high resolution DTMs for coastal regions • layer with wrecks from the UKHO Wrecks database.

The EMODnet DTM is also available by means of OGC web services (WMS, WFS, WCS, WMTS), which are specified at the EMODnet Bathymetry portal.
The original datasets themselves are not distributed but described in the metadata services, giving clear information about the background survey data used for the DTM, their access restrictions, originators and distributors and facilitating requests by users to originator.

We assembled 1.4 million National Ocean Service (NOS) bathymetric soundings from 98 lead-line and single-beam echosounder hydrographic surveys conducted from 1910 to 1999 in Cook Inlet, Alaska. These bathymetry data are available from the National Geophysical Data Center (NGDC: http://www.ngdc.noaa.gov), which archives and distributes data that were originally collected by the NOS and others. While various bathymetry data have been downloaded previously from NGDC, compiled, and used for a variety of projects, our effort differed in that we compared and corrected the digital bathymetry by studying the original analog source documents - digital versions of the original survey maps, called smooth sheets. Our editing included deleting erroneous and superseded values, digitizing missing values, and properly aligning all data sets to a common, modern datum. There were six areas where these older surveys were superseded by compilations of reduced-resolution multibeam surveys. We digitized 12,000 features, such as rocky reefs, kelp beds, rocks and islets, adding them to what was originally available, and creating the most thorough source (n = 18,000) of these typically shallow, inshore features. We also digitized 2,418 km of the mainland and 529 km of island shoreline, generally at a resolution of 1:20,000, and digitized 9,271 verbal surficial sediment descriptions from the smooth sheets. The depth surface, shoreline, inshore features, and sediment data sets are mostly produced at a scale of 1:20,000.

**CHS NONNA Data Portal was last updated: March 30, 2025 ** The Canadian Hydrographic Service (CHS) offers a complete inventory of bathymetric data free to the general public for non-navigational use called 'CHS NONNA' for the 'NON-NAvigational' purpose of the data. The product is available in a spatial resolution of 10 metres or 100 metres. To directly access the CHS NONNA Data Portal please follow this link - https://data.chs-shc.ca/login (Note: The data portal is NOT compatible with Internet Explorer browser). Terms of Use The Canadian Hydrographic Service (CHS) NONNA Data products are for NON-NAVIGATIONAL USE ONLY. Please see the Open Data Licence below and the CHS NONNA LICENCE viewable on https://data.chs-shc.ca/login and downloadable with the NONNA data, for the full terms and conditions governing the use of this data. ----- PRODUCT DESCRIPTION ----- The CHS NONNA-10 NONNA-100 and NONNA Package Bathymetric Data products represent a consolidation of digital bathymetric sources managed by the CHS in Canadian jurisdiction. The « NONNA » refers to NON-NAvigational. The « 10 » or « 100 » references the approximate resolution (in metres) of the data. NONNA Packages A NONNA Package is a ZIP file containing a collection of NONNAP datasets to ease the download of large amounts of high resolution data. Packages are currently available for data sources of approximately 10 metre resolution. The «P10 » refers to the Packages and approximate resolution (in metres) of the data. The CHS NONNA-10 individual product coverage (resolution) is as follows: • South of 68°N the products = 0.1° latitude X 0.1° longitude (0.0001 degrees) • 68°N-80°N the products = 0.1° latitude X 0.2° longitude (0.0002 degrees) • 80°N and north the products = 0.1° latitude X 0.4° longitude (0.0004 degrees) The CHS NONNA-100 individual product coverage (resolution) is as follows: • South of 68°N the products = 1° latitude X 1° longitude (0.001 degrees) • 68°N-80°N the products = 1° latitude X 2° longitude (0.002 degrees) • 80°N and north the products = 1° latitude X 4° longitude (0.004 degrees) The CHS NONNA-P10 Packages are ZIP files that contain product coverage (resolution) defined as: • South of 68°N the products = 1° latitude X 1° longitude (0.0001 degrees) • 68°N-80°N the products = 1° latitude X 2° longitude (0.0002 degrees) • 80°N and north the products = 1° latitude X 4° longitude (0.0004 degrees) ----- DATUM ----- All CHS NONNA data sources are horizontally referenced to the World Geodetic System 1984 (WGS84) ESPG:4326 and vertically referenced to Chart Datum (CD), a tidal or water level datum that is locally derived and, of which, the depth of water should seldom fall below. For more information on vertical references visit: https://tides.gc.ca/tides/en/vertical-datum-chart-references ----- DATA PRESENTATION ----- CHS NONNA products adhere to the following naming convention: NONNAXXX_SouthwestCorner Example: NONNAP10_4360N07940W • NONNAP10 = the product NONNAP10 • 4360N07940W = the southwest corner of the NONNA cell. These products are available to view, query and download via the CHS NONNA Data Portal. The following formats are available for download: • 32-bit GeoTIFF • ASCII++ (XYZ) • CSAR • BAG These formats can be opened using various GIS applications. Alternatively, the CHS NONNA products can be accessed via Web Map Service (WMS), Web Coverage Service (WCS) or Web Map Tile Service (WMTS) links: WMS https://nonna-geoserver.data.chs-shc.ca/geoserver/wms?request=GetCapabilities WMTS https://nonna-geoserver.data.chs-shc.ca/geoserver/gwc/service/wmts?request=GetCapabilities WCS https://nonna-geoserver.data.chs-shc.ca/geoserver/wcs?request=GetCapabilities Note Gaps in the data may be visible where modern surveys have not yet been conducted, the data is not updated to Chart Datum (CD) or where legacy data has not yet been digitized. In addition, there may be data sources removed from the Data Portal for further processing in the CHS’ Bathymetric Database, and will not be available until such work is complete. Data sources included in the NONNA products may not have been subjected to the same level of quality assurance as those in official navigational products. Help New users of the CHS NONNA Data Portal are encouraged to fully review the 'CHS NONNA Data Portal Guidance Document' (PDF) which is available below in the RESOURCES section of this page.

Accurate coastal wave and hydrodynamic modelling relies on quality bathymetric input. Many national scale modelling studies, hindcast and forecast products, have, or are currently using a 2009 digital elevation model (DEM), which does not include recently available bathymetric surveys and is now out of date. There are immediate needs for an updated national product, preceding the delivery of the AusSeabed program’s Global Multi-Resolution Topography for Australian coastal and ocean models. There are also challenges in stitching coarse resolution DEMs, which are often too shallow where they meet high-resolution information (e.g. LiDAR surveys) and require supervised/manual modifications (e.g. NSW, Perth, and Portland VIC bathymetries). This report updates the 2009 topography and bathymetry with a selection of nearshore surveys and demonstrates where the 2009 dataset and nearshore bathymetries do not matchup. Lineage: All of the datasets listed in Table 1 (see supporting files) were used in previous CSIRO internal projects or download from online data portals and processed using QGIS and R’s ‘raster’ package. The Perth LiDAR surveys were provided as points and gridded in R using raster::rasterFromXYZ(). The Macquarie Harbour contour lines were regridded in QGIS using the TIN interpolator. Each dataset was mapped with an accompanying Type Identifier (TID) following the conventions of the GEBCO dataset. The mapping went through several iterations, at each iteration the blending was checked for inconstancy, i.e., where the GA250m DEM was too shallow when it met the high-resolution LiDAR surveys. QGIS v3.16.4 was used to draw masks over inconstant blending and GA250 values falling within the mask and between two depths were assigned NA (no-data). LiDAR datasets were projected to +proj=longlat +datum=WGS84 +no_defs using raster::projectRaster(), resampled to the GA250 grid using raster::resample() and then merged with raster::merge(). Nearest neighbour resampling was performed for all datasets except for GEBCO ~500m product, which used the bilinear method. The order of the mapping overlay is sequential from TID = 1 being the base, through to 107, where 0 is the gap filled values.

Permissions are required for all code and internal datasets (Contact Julian OGrady).

Originally designed for military use, the multibeam echosounder has proved very useful for nautical charting, oceanographic research and modeling, habitat classification, maritime commerce, and recreational applications. The Multibeam Bathymetry Database at NCEI collects and archives multibeam data from the earliest commercial installations (circa 1980) through today's modern high-resolution collections. Data are acquired from a variety of primarily government and academic sources (see individual cruise metadata records for source information) and consist of the raw (as collected) sonar data files. Datasets may also include processed or edited versions of the sonar data, ancillary data, derived products, and/or metadata for the data collection. The Multibeam Bathymetry Database provides data that span the globe and are discoverable and accesible via map interface or text-only search options.

A 1/3 arc-second Mean Lower Low Water bathymetric DEM of NOS hydrographic survey data in Indian River, FL.

The "EMODnet Digital Bathymetry (DTM)- 2022" is a multilayer bathymetric product for Europe’s sea and oversea basins covering: • the Greater North Sea, including the Kattegat and stretches of water such as Fair Isle, Cromarty, Forth, Forties,Dover, Wight, and Portland • the English Channel and Celtic Seas • Western Mediterranean, the Ionian Sea and the Central Mediterranean Sea • Iberian Coast and Bay of Biscay (Atlantic Ocean) • Adriatic Sea (Mediterranean) • Aegean - Levantine Sea (Mediterranean). • Madeira and Azores (Macaronesia) • Baltic Sea • Black Sea • Norwegian and Icelandic Seas • Canary Islands (Macaronesia) • Arctic region and Barentz Sea and the Caribbean Sea. The DTM is based upon 21937 bathymetric survey data sets and Composite DTMs that have been gathered from 64 data providers from 28 countries riparian to European seas and beyond. Also Satellite Derived Bathymetry data products have been included fro Landsat 8 and Sentinel satellite images. Areas not covered by observations are completed by integrating GEBCO 2022 and IBCAO V4. The source reference layer in the portal viewing service gives metadata of the data sets used with their data providers; the metadata also acknowledges the data originators. The incorporated survey data sets itself can be discovered and requested for access through the Common Data Index (CDI) data discovery and access service that in December 2022 contained > 41.000survey data sets from European data providers for global waters. The Composite DTMs can be discovered through the Sextant Catalogue service. Both discovery services make use of SeaDataNet standards and services and have been integrated in the EMODnet portal (https://emodnet.ec.europa.eu/en/bathymetry#bathymetry-services ). In addition, the EMODnet Map Viewer (https://emodnet.ec.europa.eu/geoviewer/ ) gives users wide functionality for viewing and downloading the EMODnet digital bathymetry such as: • water depth (refering to the Lowest Astronomical Tide Datum - LAT) in gridded form on a DTM grid of 1/16 * 1/16 arc minute of longitude and latitude (ca 115 * 115 meters). • option to view depth parameters of individual DTM cells and references to source data • option to download DTM in 58 tiles in different formats: ESRI ASCII, XYZ, EMODnet CSV, NetCDF (CF), GeoTiff and SD • option to visualize the DTM in 3D in the browser without plug-in • layer with a number of high resolution DTMs for coastal regions • layer with wrecks from the UKHO Wrecks database. The EMODnet DTM is also available by means of OGC web services (WMS, WFS, WCS, WMTS), which are specified at the EMODnet Bathymetry portal. The original datasets themselves are not distributed but described in the metadata services, giving clear information about the background survey data used for the DTM, their access restrictions, originators and distributors and facilitating requests by users to originator.

This part of USGS Data Series 935 (Cochrane, 2014) presents bathymetry and topography data for the Offshore of Tacoma, California, map area, a part of the Southern Salish Sea Habitat Map Series. The data for this map area are a combination of topography extracted from a pre-existing Digital Elevation Model (DEM) merged with bathymetry data that were collected by the National Oceanic and Atmospheric Administration (NOAA) using multibeam sonar systems. The merged data are available for download in a single zip file (BathyTopo_OffshoreTacoma.zip).

Second version of a bathymetric map of the Baker-Martinez fjord complex (Chile, 48°S) constructed from multiple data sets: multibeam echosounder data of Baker channel (Harada et al., 2008) and of Steffen fjord and Baker river delta (Vandekerkhove et al.), single beam echosounder data of Martinez channel (R/V Sur-Austral 2015/2016) and Jorge Montt fjord (Rivera et al., 2012, Moffat, 2014 and additional data from C. Moffat) and individual bathymetry points (digitized using Global Mapper software) from two SHOA nautical charts (SHOA, 2001, 2008). The heterogeneous data with distinct spatial resolution was gridded using the kriging method (3.6 arc-second resolution) in Surfer from Golden Software. Compared to the first version (Piret et al., 2017), this new version features improved bathymetry for the Martinez Channel. We intend to update this map when new data sets become available. The data file is in the Golden Software Surfer format 7 grid format and is suitable for import in ODV’s "Section View" windows following sections 3.3 and 3.4 of the Ocean Data View manual version 5.0: https://odv.awi.de/fileadmin/user_upload/odv/misc/HowTo.pdf. Geographic (unprojected lat/lon) Coordinate System – World Geodetic System 1984 (WGS84). The previous version of this bathymetry is available at https://doi.org/10.6084/m9.figshare.5285521.v3 (figshare).

ArcInfo GRID format data generated from the 2000 multibeam sonar survey of Crater Lake, Oregon. The data include high-resolution bathymetry and calibrated acoustic backscatter. Data are also available as ASCII xyz format (see data download page of https://doi.org/10.3133/ds72)

Overview

This dataset contains global bathymetry, or water depth, measurements from the General Bathymetric Chart of the Oceans (GEBCO), converted into the format needed for WRF's Pre-processing System (WPS). The data are read in for the use of a depth-dependent water surface roughness scheme.

Data Details

File is zipped directory topobath_30s which includes the following files: .txt: index

.bil: 08401-09600.13201-14400 10801-12000.15601-16800 14401-15600.13201-14400 18001-19200.15601-16800 20401-21600.15601-16800 22801-24000.15601-16800 25201-26400.15601-16800 08401-09600.14401-15600 10801-12000.16801-18000 14401-15600.14401-15600 18001-19200.16801-18000 20401-21600.16801-18000 22801-24000.16801-18000 25201-26400.16801-18000 08401-09600.15601-16800 12001-13200.13201-14400 14401-15600.15601-16800 18001-19200.18001-19200 20401-21600.18001-19200 22801-24000.18001-19200 25201-26400.18001-19200 08401-09600.16801-18000 12001-13200.14401-15600 14401-15600.16801-18000 18001-19200.19201-20400 20401-21600.19201-20400 22801-24000.19201-20400 26401-27600.16801-18000 09601-10800.13201-14400 12001-13200.15601-16800 15601-16800.15601-16800 19201-20400.14401-15600 21601-22800.14401-15600 24001-25200.14401-15600 26401-27600.18001-19200 09601-10800.14401-15600 12001-13200.16801-18000 15601-16800.16801-18000 19201-20400.15601-16800 21601-22800.15601-16800 24001-25200.15601-16800 27601-28800.16801-18000 09601-10800.15601-16800 13201-14400.13201-14400 15601-16800.18001-19200 19201-20400.16801-18000 21601-22800.16801-18000 24001-25200.16801-18000 27601-28800.18001-19200 09601-10800.16801-18000 13201-14400.14401-15600 16801-18000.16801-18000 19201-20400.18001-19200 21601-22800.18001-19200 24001-25200.18001-19200 10801-12000.13201-14400 13201-14400.15601-16800 16801-18000.18001-19200 19201-20400.19201-20400 21601-22800.19201-20400 24001-25200.19201-20400 10801-12000.14401-15600 13201-14400.16801-18000 18001-19200.14401-15600 20401-21600.14401-15600 22801-24000.14401-15600 25201-26400.14401-15600

Data Quality

The provided 30 arc second GEBCO bathymetry data were masked with WRF's 30-second land mask data and over-water measurements (negative in GEBCO) were converted to depth (positive number relative to water surface). The data were then compared to existing lake depth values in WRF where only minor differences were found.

Uncertainty

The land mask data and bathymetry data are not from the same source but were collected in a similar fashion. Areas may exist where GEBCO is providing over-water information while WRF's land mask shows it is land, and vice-versa. These situations are accounted for by setting the depth to a default value where ever inconsistencies are found.

Constraints

This data are currently set up for ease of use with WRF and proper care should be taken when trying to use the data for other purposes. It is recommended that the GEBCO data be downloaded directly in this case.