ALACE subsurface drifter data in South Pacific, for March 1995 (NODC Accession 9500149)

browse graphicPreview graphic
The ALACE (Autonomous LAgrangian Circulation Explorer) is a subsurface drifter, periodically rising to the surface to relay data to ARGOS. Instrument location is then obtained from ARGOS. An ALACE profiler collects data on ascent and relays a compressed data set to ARGOS. The amount of time spent at its neutrally-buoyant depth, and then at the surface, is variable, dependent upon the deployment site and the main scientific objective of the ALACE. Profiling ALACEs generally complete a cycle every 8-10 days, spending 24 hours at the surface transmitting to ARGOS.
  • Cite as: Sherman, Jeff; University of California - San Diego > Scripps Institution of Oceanography (2010). ALACE subsurface drifter data in South Pacific, for March 1995 (NODC Accession 9500149). Version 1.2. National Oceanographic Data Center, NOAA. Dataset. [access date]
gov.noaa.nodc:9500149
Download Data
  • HTTPS (download)
    Navigate directly to the URL for data access and direct download.
  • FTP (download)
    These data are available through the File Transfer Protocol (FTP). You may use any FTP client to download these data.
Distribution Formats
  • Originator data format
Ordering Instructions Data may be searched and downloaded using online services provided by NCEI using the online resource URLs in this record. Contact NCEI Information Services for custom orders. When requesting data from NCEI, the desired data set may be referred to by the unique package identification number listed in this metadata record.
Distributor DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
301-713-3277
NCEI.Info@noaa.gov
Dataset Point of Contact Information Services
DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
301-713-3277
NCEI.Info@noaa.gov
Time Period 1995-03-01 to 1995-03-22
Spatial Bounding Box Coordinates
N: 35.12
S: -70.46
E: 10.48
W: -155.26
Spatial Coverage Map
General Documentation
Publication Dates
  • publication: 2010-12-18
  • revision: 2013-03-19
Edition 1.2
Data Presentation Form Digital table - digital representation of facts or figures systematically displayed, especially in columns
Dataset Progress Status Complete - production of the data has been completed
Data Update Frequency As needed
Supplemental Information
DEPTH-AVERAGING

A profile is taken on ascent, with T sampled every 3 s while ALACE is
ascending at 10-15 cm/s. The data is depth-averaged and compressed for
transmission through ARGOS. The degree of averaging increases with depth.
For instance, a profile might start out with 5 m resolution from 0-200 m
depth, switching to 10 m resolution from 200-800 m, followed by 20 m
resolution to 1200 m.

SENSOR DESCRIPTION

TEMPERATURE: A thermistor bead from YSI (YSI-44016) is used, having a
typical drift of <0.01 deg. C over 1 year, increasing to 0.02 deg. C over 8
years.
Laboratory calibration of thermistors typically have less than 0.002 deg. C
standard deviation. The largest error comes from the 12-bit a/d (Linear
Technology's LTC1290) which resolves T to 0.01-0.02 deg C, with better
resolution obtained at low temperatures.

PRESSURE: A Paines 210-38 with 0-3000 PSI range is used. Quoted accuracy
from thermal drift, non-linearity, hysteresis, and repeatability is ~10
dBar. Observations of a few units in laboratory testing suggest an
accuracy of ~5 dBar.


OTHER PROFILING ALACEs: At this time, there are a few CTD ALACEs.
Sampling and data format are the same as the temperature profiler, with the
addition of conductivity also being transmitted. The units have not been
thoroughly tested for long-term accuracy, and thus their data sets are not
ready for release.

SUBSURFACE DRIFT RATE
The difference in locations between profiles includes the subsurface drift
and the 24 hour surface drift in one complete ALACE cycle. Therefore the
NODC data set itself could be used to estimate deep currents, but accuracy
would be limited by the unknown surface drift. Dr. Davis uses a fairly
sophisticated algorithm to extrapolate the surface drift from the set of
ARGOS fixes for the 24 hours ALACE is transmitting.

I believe Russ Davis's intent is to provide temperature profiles in the
same format as the NODC XBT data set, so people can readily use the ALACE
data without requiring any further programming.
Purpose Basic research
Use Limitations
  • accessLevel: Public
  • 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 data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives.
Dataset Citation
  • Cite as: Sherman, Jeff; University of California - San Diego > Scripps Institution of Oceanography (2010). ALACE subsurface drifter data in South Pacific, for March 1995 (NODC Accession 9500149). Version 1.2. National Oceanographic Data Center, NOAA. Dataset. [access date]
Cited Authors
Contributors
Resource Providers
Publishers
Theme keywords NODC DATA TYPES THESAURUS NODC OBSERVATION TYPES THESAURUS WMO_CategoryCode
  • oceanography
Global Change Master Directory (GCMD) Science and Services Keywords
  • EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PRESSURE
  • EARTH SCIENCE > OCEANS > OCEAN PRESSURE > WATER PRESSURE
  • EARTH SCIENCE > OCEANS > OCEAN TEMPERATURE > WATER TEMPERATURE
Data Center keywords Global Change Master Directory (GCMD) Data Center Keywords
  • DOC/NOAA/NESDIS/NODC > National Oceanographic Data Center, NESDIS, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
NODC COLLECTING INSTITUTION NAMES THESAURUS NODC SUBMITTING INSTITUTION NAMES THESAURUS
Instrument keywords NODC INSTRUMENT TYPES THESAURUS Global Change Master Directory (GCMD) Instrument Keywords
  • BATHYTHERMOGRAPHS
  • CTD > Conductivity, Temperature, Depth
Place keywords NODC SEA AREA NAMES THESAURUS Global Change Master Directory (GCMD) Location Keywords
  • OCEAN > ATLANTIC OCEAN > NORTH ATLANTIC OCEAN
  • OCEAN > ATLANTIC OCEAN > SOUTH ATLANTIC OCEAN
  • OCEAN > PACIFIC OCEAN > SOUTH PACIFIC OCEAN
Keywords NCEI ACCESSION NUMBER
Use Constraints
  • Cite as: Sherman, Jeff; University of California - San Diego > Scripps Institution of Oceanography (2010). ALACE subsurface drifter data in South Pacific, for March 1995 (NODC Accession 9500149). Version 1.2. National Oceanographic Data Center, NOAA. Dataset. [access date]
Access Constraints
  • 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.
Fees
  • Digital data may be downloaded from NCEI at no charge in most cases. For custom orders of digital data or to obtain a copy of analog materials, please contact NCEI Information Services for information about current fees.
Lineage information for: dataset
Processing Steps
  • 2010-12-18T17:52:13 - NCEI Accession 9500149 v1.1 was published.
  • 2013-03-19T17:48:15 - NCEI Accession 9500149 was revised and v1.2 was published.
    Rationale: Updates were received for this data set. These updates were copied into the data/0-data/ directory of this accession. These updates may provide additional files or replace obsolete files. This version contains the most complete and up-to-date representation of this archival information package. All of the files received prior to this update are available in the preceding version of this accession.
Output Datasets
Lineage information for: repository
Processing Steps
  • 2015-04-22T00:00:00 - NOAA created the National Centers for Environmental Information (NCEI) by merging NOAA's National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC), and National Oceanographic Data Center (NODC), including the National Coastal Data Development Center (NCDDC), per the Consolidated and Further Continuing Appropriations Act, 2015, Public Law 113-235. NCEI launched publicly on April 22, 2015.
Acquisition Information (collection)
Instrument
  • bathythermograph - uBT
  • CTD
Last Modified: 2017-11-01T12:26:24
For questions about the information on this page, please email: NODC.DataOfficer@noaa.gov