gov.noaa.nodc:0208105 eng utf8 dataset NOAA National Centers for Environmental Information ncei.info@noaa.gov https://www.ncei.noaa.gov/contact HTTPS NOAA Contact Information Information for contacts at NCEI. information custodian 2026-04-02T17:05:54Z ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) Global monthly climatology of deep sound channel axis, sonic layer depth, and other underwater acoustic parameters, total of 14, derived from World Ocean Atlas 2018 (NCEI Accession 0208105) 2019-12-18 publication 2019-12-13 creation International DOI Foundation (IDF) 10.25921/2x35-sc93 NOAA National Centers for Environmental Information gov.noaa.nodc:0208105 NCEI Archive Management System 0208105 NOAA National Centers for Environmental Information ncei.info@noaa.gov https://www.ncei.noaa.gov/contact HTTPS NCEI Contact Information Information for contacts at NCEI. information publisher Peter C. Chu US Navy/Naval Postgraduate School pcchu@nps.edu resourceProvider US Navy/Naval Postgraduate School resourceProvider Peter Chu US Navy/Naval Postgraduate School pcchu@nps.edu pointOfContact Chenwu Fan US Navy/Naval Postgraduate School fan@nps.edu collaborator Chu, Peter C US Navy; Naval Postgraduate School author Fan, Chenwu US Navy; Naval Postgraduate School fan@nps.edu author tableDigital This dataset contains global monthly climatology of sonic layer depth, surface sound speed, and other underwater acoustic parameters, total of 14, derived from World Ocean Atlas 2018 profile data. Data are partitioned into 12 monthly and annual mean files. Acoustics is most effective in undersea detection, localization, and communication. However, there is no global climatology of underwater acoustic parameters. A multiple gradient method is used to analyze the sound speed profile, which is calculated from temperature and salinity profiles using the Thermodynamic Equation of Seawater-2010 (TEOS-10) to get the sonic layer depth (SLD), deep sound channel (DSC) axis depth, and second sound channel (SSC) axis depth from the gridded (0.25 degree, and 1 degree) temperature and salinity fields of the National Centers for Environmental Information (NCEI) world ocean atlas 2018. With the given (SLD, DSC axis depth, SSC axis depth), the other acoustic parameters are calculated such as sound speed at the surface, sound speed at the SLD, sound speed at the DSC axis, sound speed at the SSC axis, minimum cut-off frequency, in-layer gradient, below-layer gradient, surface duct cut-off frequency, deep sound channel strength, critical depth of the DSC, depth excess, and second sound channel strength. Data are in netcdf. Enhancement of WOA18 usage into underwater acoustics completed historicalArchive NOAA National Centers for Environmental Information ncei.info@noaa.gov https://www.ncei.noaa.gov/contact HTTPS NCEI Contact Information Information for contacts at NCEI. information pointOfContact asNeeded https://www.ncei.noaa.gov/access/metadata/landing-page/bin/gfx?id=gov.noaa.nodc:0208105 Preview graphic PNG 0208105 NCEI ACCESSION NUMBER 2019-12-07 publication SOUND VELOCITY theme NODC DATA TYPES THESAURUS bathythermograph - MBT bathythermograph - XBT buoy - moored buoy CTD profiling float instrument NODC INSTRUMENT TYPES THESAURUS derived products physical theme NODC OBSERVATION TYPES THESAURUS US Navy/Naval Postgraduate School dataCentre NODC SUBMITTING INSTITUTION NAMES THESAURUS World-Wide Distribution place NODC SEA AREA NAMES THESAURUS oceanography theme WMO_CategoryCode 2012-09-15 publication DOD/USNAVY/NPS > Naval Postgraduate School, U.S. Navy, U.S. Department of Defense dataCentre Global Change Master Directory (GCMD) Data Center Keywords 2026 revision 24 Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA) Greenbelt MD https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords HTTPS GCMD Keyword Forum Page Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords information custodian EARTH SCIENCE > OCEANS > OCEAN ACOUSTICS > ACOUSTIC VELOCITY theme Global Change Master Directory (GCMD) Science Keywords 2026 revision 24 Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA) Greenbelt MD https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords HTTPS GCMD Keyword Forum Page Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords information custodian CTD > Conductivity, Temperature, Depth MBT > Mechanical Bathythermographs XBT > Expendable Bathythermographs instrument Global Change Master Directory (GCMD) Instrument Keywords 2026 revision 24 Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA) Greenbelt MD https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords HTTPS GCMD Keyword Forum Page Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords information custodian GEOGRAPHIC REGION > GLOBAL OCEAN place Global Change Master Directory (GCMD) Location Keywords 2026 revision 24 Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA) Greenbelt MD https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords HTTPS GCMD Keyword Forum Page Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords information custodian DK19XR Send2NCEI Submission Package ID accessLevel: public otherRestrictions Cite as: Chu, Peter C; Fan, Chenwu (2019). Global monthly climatology of deep sound channel axis, sonic layer depth, and other underwater acoustic parameters, total of 14, derived from World Ocean Atlas 2018 (NCEI Accession 0208105). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://doi.org/10.25921/2x35-sc93. Accessed [date]. Distribution liability: NOAA and NCEI make no warranty, expressed or implied, regarding these data, nor does the fact of distribution constitute such a warranty. NOAA and NCEI cannot assume liability for any damages caused by any errors or omissions in these data. If appropriate, NCEI can only certify that the data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives. otherRestrictions Use liability: NOAA and NCEI cannot provide any warranty as to the accuracy, reliability, or completeness of furnished data. Users assume responsibility to determine the usability of these data. The user is responsible for the results of any application of this data for other than its intended purpose. Chu, Peter C.; Fan, Chenwu (2019). Mixed layer depth, isothermal layer depth, barrier layer depth, and other upper ocean thermohaline parameters, total of 17, derived from climatological gridded vertical profiles from the World Ocean Atlas 2018 (NCEI Accession 0205198). NOAA National Centers for Environmental Information. Dataset. https://doi.org/10.25921/j3v2-jy50. 2019-10-23 publication International DOI Foundation (IDF) https://doi.org/10.25921/j3v2-jy50 NOAA National Centers for Environmental Information gov.noaa.nodc:0205198 https://doi.org/10.25921/j3v2-jy50 HTTPS https://doi.org/10.25921/j3v2-jy50 Related dataset information Chu, Peter C. US Navy; Naval Postgraduate School author Fan, Chenwu US Navy; Naval Postgraduate School fan@nps.edu author NOAA National Centers for Environmental Information (NCEI) publisher tableDigital crossReference collection eng; USA utf8 environment oceans -180 180 -90 90 1950-01-01 2018-12-31 NOAA National Centers for Environmental Information +1-301-713-3277 ncei.info@noaa.gov pointOfContact In most cases, electronic downloads of the data are free. However, fees may apply for custom orders, data certifications, copies of analog materials, and data distribution on physical media. Contact NCEI for other distribution options and instructions. Originator data format 784.596 https://doi.org/10.25921/2x35-sc93 HTTPS Web browser NCEI Dataset Landing Page Navigate directly to the URL for a descriptive web page with download links. information https://www.ncei.noaa.gov/archive/accession/oas/208105 HTTPS Web browser Descriptive Information Navigate directly to the URL for a descriptive web page with download links. information https://www.ncei.noaa.gov/archive/accession/download/208105 HTTPS Web browser HTTPS Navigate directly to the URL for data access and direct download. download ftp://ftp-oceans.ncei.noaa.gov/nodc/archive/arc0151/0208105/ FTP Any FTP client FTP These data are available through the File Transfer Protocol (FTP). FTP is no longer supported by most internet browsers. You may copy and paste the FTP link to the data into an FTP client (e.g., FileZilla or WinSCP). download dataset NCEI Accession 0208105 v1.1 was published. 2019-12-18T19:55:47Z NCEI Accession 0208105 v1.1 publication https://www.ncei.noaa.gov/archive/accession/0208105/1.1 HTTPS NCEI Accession 0208105 v1.1 published 2019-12-18T19:55:47Z download dataset Parameter or Variable: acoustic parameters (calculated); Units: m; Observation Category: other; Sampling Instrument: WOA 2018; Sampling and Analyzing Method: Same as WOA18; Data Quality Method: same as WOA18 asNeeded Metadata are developed, maintained and distributed by NCEI. Updates are performed as needed to maintain currentness. NOAA National Centers for Environmental Information custodian bathythermograph - MBT bathythermograph - MBT Mechanical BathyThermograph bathythermograph - XBT bathythermograph - XBT eXpendable BathyThermograph buoy - moored buoy buoy - moored buoy a moored buoy does not measure anything. it is a platform for instruments, which do measure things. CTD CTD Conductivity-Temperature-Depth probe profiling float profiling float PALACE and other types of profiling drifters any one of several types of free-drifting (floating) instrument packages that measure one or more water column parameters, such as temperature, salinity, etc., along with reporting the date, time, and location of the measurements taken over time. Examples include the P-ALACE or PALACE floats, drifting buoys, etc.