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    • Ocean currents from lowered acoustic Doppler current profilers (LADCP) aboard various cruises of the World Ocean Circulation Experiment (WOCE) project from 1991 to 1997

    Metadata Updated: December 1, 2023

    This collection holds the Lowered Acoustic Doppler Current Profile (LADCP) estimates of ocean currents collected for the World Ocean Circulation Experiment (WOCE) project. LADCPs estimate deep ocean absolute currents and shear. The project has been completed (WOCE ended in 1999).

    ADCPs use the Doppler shift of an outgoing frequency along a beam to return measured velocity along that beam. ADCPs typically have 4 beams, allowing measurement of velocity in 3 dimensions, in bins of varying distance from the transducer head. In this application, the ADCP is mounted on a CTD rosette frame and lowered along with the rest of the package, hence called Lowered ADCP ("LADCP"). LADCP requires less ship time in estimating deep currents as compared to historic measuring systems such as Pegasus systems. The goal is to determine water velocities to the full depth of the ocean for each LADCP deployment. Ocean velocities are very small (few cm/s), especially in the deep water. The package is typically lowered or raised at 1m/s for much of the water column, creating a challenging data processing situation. To reduce the LADCP measurements, one must utilize other data streams such as CTD at both standard levels and at the highest frequency of recording, GPS positions, ship navigation, ocean depth, and shipboard ADCP.

    Lowered ADCP data requires ancillary information to improve the processed data product. Over generations, the processing has improved and these ancillary components are systematically collected along with the LADCP data. In older datasets, they may be missing entirely. The directory structure and naming convention for the submitted LADCP datasets attempt to rationalize 20 years of data acquisition and processing by a collection of scientists who were inventing the field of LADCP acquisition and processing, so there is some variety in the organization and naming of the original datasets. Evolution of the instrumentation and processing techniques have continued.

    For the NCEI archive, three levels are defined: 1) Level-0, raw LADCP and ancillary data streams of the down- and up-cast, 2) Level-1, processed LADCP and ancillary data streams for the down-, up-, and averaged cast, and 3) Level-2 science-ready subset of select parameters. Presently only Levels 0 and 1 will be archived since work continues for defining error associated with Level 3. Note, Level 1 data are "as processed" based on the processing code pertinent at that time. There is one processed file per station cast. The ancillary streams of Level-1 are the basic oceanographic variables of interest, and may also include a variety of additional fields associated with the processing.

    Access & Use Information

    License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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    Dates

    Metadata Date 2023-09-06T19:09:49Z
    Metadata Created Date December 4, 2020
    Metadata Updated Date December 1, 2023
    Reference Date(s) October 2, 2019 (publication), May 7, 2020 (revision)
    Frequency Of Update asNeeded

    Metadata Source

    Harvested from NOAA/NESDIS/ncei/accessions

    Other Data Resources

    Graphic Preview

    Preview graphic

    Additional Metadata

    Resource Type Series
    Metadata Date 2023-09-06T19:09:49Z
    Metadata Created Date December 4, 2020
    Metadata Updated Date December 1, 2023
    Reference Date(s) October 2, 2019 (publication), May 7, 2020 (revision)
    Responsible Party (Point of Contact)
    Contact Email
    Guid gov.noaa.nodc:WOCE-LADCP
    Access Constraints Cite as: Chereskin, Teresa K.; Firing, Eric; Hacker, Peter; Hummon, Julia M.; Kosro, P. Michael (2019). Ocean currents from lowered acoustic Doppler current profilers (LADCP) aboard various cruises of the World Ocean Circulation Experiment (WOCE) project from 1991 to 1997. [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://www.ncei.noaa.gov/archive/accession/WOCE-LADCP. Accessed [date]., 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.
    Bbox East Long -9.335
    Bbox North Lat 64.902
    Bbox South Lat -67.
    Bbox West Long 30.338
    Coupled Resource
    Frequency Of Update asNeeded
    Graphic Preview Description Preview graphic
    Graphic Preview File https://www.ncei.noaa.gov/access/metadata/landing-page/bin/gfx?id=gov.noaa.nodc:WOCE-LADCP
    Graphic Preview Type PNG
    Harvest Object Id e5641105-5807-402f-8c9a-f14cf336af20
    Harvest Source Id c084a438-6f6b-470d-93e0-16aeddb9f513
    Harvest Source Title NOAA/NESDIS/ncei/accessions
    Licence accessLevel: Public
    Lineage
    Metadata Language eng
    Metadata Type geospatial
    Old Spatial {"type": "Polygon", "coordinates": [[[30.338, -67.0], [-9.335, -67.0], [-9.335, 64.902], [30.338, 64.902], [30.338, -67.0]]]}
    Progress completed
    Spatial Data Service Type
    Spatial Reference System
    Spatial Harvester True
    Temporal Extent Begin 1991-05-31
    Temporal Extent End 1997-11-19

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