Search the data

Metadata Report for BODC Series Reference Number 1763633


Metadata Summary

Data Description

Data Category Bathymetry
Instrument Type
NameCategories
Teledyne RDI Workhorse Navigator 150 kHz Doppler Velocity Log, current profiler and pressure sensor  current profilers; water temperature sensor; altimeters; platform attitude sensors
Instrument Mounting autonomous underwater vehicle
Originating Country United Kingdom
Originator Dr Adrian Jenkins
Originating Organization British Antarctic Survey
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) Ice Sheet Stability (iSTAR) Programme
Ocean under ice (iSTAR B)
 

Data Identifiers

Originator's Identifier JR294_AUTOSUBSEABEDDEPTH_M447
BODC Series Reference 1763633
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2014-02-16 18:13
End Time (yyyy-mm-dd hh:mm) 2014-02-18 03:01
Nominal Cycle Interval 2.0 seconds
 

Spatial Co-ordinates

Start Latitude 75.17005 S ( 75° 10.2' S )
End Latitude 75.02291 S ( 75° 1.4' S )
Start Longitude 101.80157 W ( 101° 48.1' W )
End Longitude 100.58293 W ( 100° 35.0' W )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor or Sampling Depth 26.53 m
Maximum Sensor or Sampling Depth 968.39 m
Minimum Sensor or Sampling Height -
Maximum Sensor or Sampling Height -
Sea Floor Depth -
Sea Floor Depth Source -
Sensor or Sampling Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor or Sampling Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum -
 

Parameters

BODC CODERankUnitsTitle
AADYAA011DaysDate (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ011DaysTime (time between 00:00 UT and timestamp)
ACYCAA011DimensionlessSequence number
ALATZZ011DegreesLatitude north
ALONZZ011DegreesLongitude east
MBANZZZZ1MetresSea-floor depth (below instantaneous sea level) {bathymetric depth} in the water body

Definition of Rank

  • Rank 1 is a one-dimensional parameter
  • Rank 2 is a two-dimensional parameter
  • Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

Problem Reports

No Problem Report Found in the Database


Data Access Policy

Open Data

These data have no specific confidentiality restrictions for users. However, users must acknowledge data sources as it is not ethical to publish data without proper attribution. Any publication or other output resulting from usage of the data should include an acknowledgment.

If the Information Provider does not provide a specific attribution statement, or if you are using Information from several Information Providers and multiple attributions are not practical in your product or application, you may consider using the following:

"Contains public sector information licensed under the Open Government Licence v1.0."


Narrative Documents

Teledyne RD Instruments Workhorse Navigator Doppler Velocity Log

The Workhorse Navigator (WHN) Doppler Velocity Log (DVL) provides precise velocity and altitude information for a variety of underwater tasks, and can be used in a standalone configuration or integrated with other navigation systems. The DVL incorporates a compass, a tilt meter, a temperature sensor and a 4-beam acoustic transducer as standard, providing bottom and water track velocities, four individual measurements of altitude, heading, tilt and acoustic echo intensity. Pressure, depth and current profiling options are also available.

High resolution data are produced using Broadband signal processing and a four-beam solution gives an independent error velocity measurement as an indicator of data quality. The three standard models are the WHN 300, WHN 600 and WHN 1200, as detailed below. Customised transducers with different frequencies are also available.

Specifications

  WHN 300 WHN 600 WHN 1200
Transducer frequency (kHz) 300 600 1200
Depth rating (m) 3000 or 6000 3000 or 6000 3000 or 6000
Temperature range (deg C) -5 to 45 -5 to 45 -5 to 45
Compass accuracy (deg) ±2 at 60 deg dip, 0.5g ±2 at 60 deg dip, 0.5g ±2 at 60 deg dip, 0.5g
Tilt accuracy (deg) ±0.5, up to ±15 ±0.5, up to ±15 ±0.5, up to ±15
Pressure and depth optional optional optional
Current profiling optional optional optional
Velocity range (m s-1) ±10 ±10 ±10
Velocity resolution (cm s-1) 0.1 0.1 0.1
Maximum ping rate (Hz) 7 7 7
Bottom velocity      
Minimum altitude (m) 1.0 0.7 0.5*
Maximum altitude (m) 200 90 30
Accuracy (cm s-1) ±0.4% ±0.2 ±0.2% ±0.1 ±0.2% ±0.1
Water reference velocity      
Minimum range (m) 1.0 0.7 0.25
Maximum range (m) 110 50 18
Layer size selectable selectable selectable
Accuracy (cm s-1) ±0.4% ±0.2 ±0.3% ±0.2 ±0.2% ±0.1

*Enhanced low-altitude tracking down to 0.25 m is available for the WHN 1200.

Further details can be found in the manufacturer's specification sheet.

BODC Processing - Autosub data

Data were received by BODC in Matlab files, with one file containing all data from the Autosub missions. The data were reformatted to QXF (a NetCDF file format) by in house software. A separate QXF file was created for data from each data type from each mission. Metadata were also extracted from the originator's file and used to populate the BODC database.

The following tables shows how the variables within the files were mapped to appropriate BODC parameter codes for each of the data types supplied:

CTD data

Originator's parameter name Origintator's units Description BODC Parameter Code BODC Units Comments
Pasub Decibars Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level PRESPR01 Dbars  
Depthasub Metres Depth below surface of the water body by profiling pressure sensor and converted to seawater depth using UNESCO algorithm DEPHPR01 Metres  
DOasub Millilitres per litre Concentration of oxygen {O2 CAS 7782-44-7} per unit volume of the water body [dissolved plus reactive particulate phase] by in-situ sensor DOXYZZ01 Micromoles per litre Conversion of *44.66 applied.
Latasub Degrees north Latitude north ALATZZ01 Degrees north  
Lonasub Degrees east Longitude east ALONZZ01 Degrees east  
Sasub PSU Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm PSALST01 Dimensionless  
Tasub Degrees Celsius Temperature of the water body TEMPPR01 Degrees Celsius  
Traasub Percent Transmittance (unspecified wavelength) per unspecified length of the water body by transmissometer. POPTZZ01 Percent  
- - Potential temperature of the water body by computation using UNESCO 1983 algorithm POTMCV01 Degrees Celsius Derived by BODC where source variables are available
- - Sigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm SIGTPR01 Kilograms per cubic metre Derived by BODC where source variables are available
- - Saturation of oxygen {O2 CAS 7782-44-7} in the water body [dissolved plus reactive particulate phase] OXYSZZ01 Percent Derived by BODC where source variables are available

Ice draft data

Originator's parameter name Origintator's units Description BODC Parameter Code BODC Units Comments
Lat_Icedraft Degrees north Latitude north ALATZZ01 Degrees north  
Lon_Icedraft Degrees east Longitude east ALONZZ01 Degrees east  
IceDraft Metres Ice draft on the water body by acoustic doppler current profiler (ADCP) ARDECI01 Metres  

Seabed depth data

Originator's parameter name Origintator's units Description BODC Parameter Code BODC Units Comments
Lat_SeabedDepth Degrees north Latitude north ALATZZ01 Degrees north  
Lon_SeabedDepth Degrees east Longitude east ALONZZ01 Degrees east  
SeabedDepth Metres Sea-floor depth (below instantaneous sea level) {bathymetric depth} in the water body MBANZZZZ Metres  

Quality control

Following transfer to QXF, the data were quality controlled using BODC's in-house visualisation software.

Originator's processing - iSTAR Autosub data

Data collection

Five Autosub missions were completed during iSTAR cruise RRS James Clark Ross JR20140126 in the Amundsen Sea. The data were collected for the Ocean2ice (iSTAR A) project which is part of the Natural Environment Research Council funded iSTAR programme.

Instruments attached to the Autosub included:

  • a Seabird CTD, with dual conductivity and temperature sensors and additional dissolved oxygen sensor and transmissometer
  • a Simrad mliti-beam echosounder, configurable as upward- or downward-looking
  • an upward-looking RDI 300 kHz ADCP
  • a downward-looking RDI 150 kHz ADCP
  • aEdgetech 2200M sub-bottom profiler and
  • a Rockland MicroRider microstructure sensor module

For more information about the Autosub missions and data collection see the cruise report

Data processing

The data collected was processed by the originator and the CTD data plus geometry data (ice draft and sea bed depth) from the ADCP ranges were supplied to BODC.</

For information about the Autosub data processing see the cruise report


Project Information

Ocean under ice: Ocean circulation and melting beneath the ice shelves of the south-eastern Amundsen Sea (iSTAR B)

Background and objectives

Ocean under ice (otherwise referred to as iSTAR B) is a project that is part of NERC's Ice Sheet Stability programme. The West Antarctic ice sheet has been observed to be changing faster than scientists had expected. There is a significant flow of ice from the Pine Island Glacier in to the sea at Pine Island Bay. The project aims to understand the rate of melting of ice in to the ocean and the relationship between this and the properties of the sea water around and beneath the glacier. It will also try to determine what the impact of even small amounts of warming of the sea water would have on the rate of ice lost. This is a challenging project because the glacier ice is between 300 and 1000 m thick and access to its base is difficult. This project was funded by the Natural Environment Research Council.

Participants

The principal investigator for the Ocean under ice project is Adrian Jenkins, British Antarctic Survey. Other participants in the project represent the following organisations:

  • British Antarctic Survey
  • University College London
  • University of Washington

Fieldwork and data collection

The project used cutting edge technology to measure the conditions at the edge of the glacier as well as the properties of the glacier itself. The ocean conditions were be measured by an Autosub (a submarine robot which carries sensors to measure water properties) under the ice in Pine Island Bay. To complement these measurements a radar was used to measure the changing thickness of the ice in the glacier and the position of the base of the glacier over an extended period of time (autonomous technology enables year-round operation). These data will be fed in to a computer model to explore how heat transported in to the area by the ocean water affects the ice shelf.

Data management

All data collected by the Ocean under ice project will be submitted to the British Oceanographic Data Centre (Autosub) or Polar Data Centre (Radar) for careful storage, quality control, archiving and distribution to scientists, education, industry and the public.

For more information about Ocean2ice see the iSTAR B project page


The Ice Sheet Stability (iSTAR) programme

Background and objectives

The iSTAR programme aims to measure the rate that ice is being lost from the West Antarctic ice sheet, and to improve our understanding of what might be driving this loss how it is changing over time. The rate of loss of water from ice in glaciers in the Antarctic (and Greenland) is more than the amount of water being deposited in these areas by precipitation. This has changed our understanding of these systems and the rate of ice loss is a matter of interest for sea level and climate research. Improving our understanding of the processes and impacts of changes to these systems is vital for better predictions for sea level rise in the future and will feed in to climate research. This programme combines scientific research of glaciers and the surrounding ocean environment (including how they impact each other). Research about the oceans was focused on the Amundsen Sea Sector of West Antarctica with instruments deployed from the research ship RRS James Clark Ross. Research about the ice was focused on Pine Island Glacier, Thwaites Glacier and Union Glacier with measurements taken during two expeditions across the ice. This programme was funded by the Natural Environment Research Council (NERC)

The programme is split in to four projects:

Ocean2ice: Processes and variability of ocean heat transport toward ice shelves in the Amundsen Sea Embayment (iSTAR A)

Ocean under ice: Ocean circulation and melting beneath the ice shelves of the south-eastern Amundsen Sea (iSTAR B)

Dynamic ice: Dynamical control on the response of Pine Island Glacier (iSTAR C)

Ice loss: The contribution to sea-level rise of the Amundsen Sea sector of Antarctica (iSTAR D)

Participants

The iSTAR research programme is managed by British Antarctic Survey (BAS) on behalf of NERC. Operational support, in the form of logistics planning and infrastructure, and Communication and Knowledge Exchange support are provided by BAS. There are four science projects and participants in these projects represent the following organisations:

  • British Antarctic Survey
  • National Oceanography Centre
  • Newcastle University
  • Scott Polar Research Institute
  • University College London
  • University of Bristol
  • University of East Anglia
  • University of Edinburgh
  • University of Leeds
  • University of Southampton
  • University of St. Andrews
  • University of Tasmania
  • University of Washington

Fieldwork and data collection

A wide range of data parameters were collected for this programme. Physical and chemical measurements of the ocean close to and next to the ice shelf were made using instruments deployed from ship, on moorings, on autonomous platforms and seal tags. Measurements were also made of the glaciers and ice shelfs including radar and seismic surveys and ice cores. There were also meteorological and atmospheric measurements taken. For more information about the data collected on each of the four projects see the project web pages.

Data management

Data management for ocean data will be done by the British Oceanographic Data Centre whilst ice data will be managed by the Polar Data Centre.

For more information about iSTAR programme see the: iSTAR Programme Website


Data Activity or Cruise Information

Cruise

Cruise Name JR20140126 (JR294, JR295)
Departure Date 2014-01-26
Arrival Date 2014-03-08
Principal Scientist(s)Karen J Heywood (University of East Anglia School of Environmental Sciences)
Ship RRS James Clark Ross

Complete Cruise Metadata Report is available here


Fixed Station Information


No Fixed Station Information held for the Series


BODC Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

Flag Description
Blank Unqualified
< Below detection limit
> In excess of quoted value
A Taxonomic flag for affinis (aff.)
B Beginning of CTD Down/Up Cast
C Taxonomic flag for confer (cf.)
D Thermometric depth
E End of CTD Down/Up Cast
G Non-taxonomic biological characteristic uncertainty
H Extrapolated value
I Taxonomic flag for single species (sp.)
K Improbable value - unknown quality control source
L Improbable value - originator's quality control
M Improbable value - BODC quality control
N Null value
O Improbable value - user quality control
P Trace/calm
Q Indeterminate
R Replacement value
S Estimated value
T Interpolated value
U Uncalibrated
W Control value
X Excessive difference

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

Flag Description
0 no quality control
1 good value
2 probably good value
3 probably bad value
4 bad value
5 changed value
6 value below detection
7 value in excess
8 interpolated value
9 missing value
A value phenomenon uncertain
B nominal value
Q value below limit of quantification