Metadata Report for BODC Series Reference Number 648809
Metadata Summary
Problem Reports
Data Access Policy
Narrative Documents
Project Information
Data Activity or Cruise Information
Fixed Station Information
BODC Quality Flags
SeaDataNet Quality Flags
Metadata Summary
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Problem Reports
The current meter only shows readings between 85o and 135o this is consistent with the current meter's vein being tangled in the mooring line and becoming tilted. The full deployment of this data are affected and have been flagged with the appropriate quality control flag.
Data Access Policy
Open Data supplied by Natural Environment Research Council (NERC)
You must always use the following attribution statement to acknowledge the source of the information: "Contains data supplied by Natural Environment Research Council."
Narrative Documents
Aanderaa Recording Current Meter Model 7/8
Manufacturer's specifications: recording unit height 49.5cm (RCM8 52.0cm), diameter 12.8cm, vane size 48.5x50.0cm. Meter is designed for depths down to 2000m (RCM8 6000m). It incorporates a spindle which is shackled to the mooring line. The meter is attached to the spindle through a gimbal mounting which permits a maximum 27° deviation of the spindle from the vertical, the meter still remaining horizontal.
Meter comprises :
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Paddle wheel rotor magnetically coupled to an electronic counter
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Vane, which aligns instrument with current flow, has a balance weight ensuring static balance and tail fins to ensure dynamic balance in flows up to 250cm/s.
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Magnetic compass (needle is clamped to potentiometer ring) - direction recorded with 0.35° resolution, 5° accuracy for speeds 5 to 100cm/s, 7.5° accuracy for remaining speeds within 2.5 to 200cm/s range.
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Quartz clock, accuracy better than 2 sec/day within temperature range 0 to 20°C.
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Thermistor (temperature sensor), standard range -2.46 to 21.48°C (max on high range 36.04°C), accuracy 0.05°C, resolution 0.1 per cent of range, 63 per cent response time 12sec.
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Inductive cell conductivity sensor (optional), range 0 to 70mmho/cm standard resolution 0.1 per cent of range.
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Silicon piezoresistive bridge, standard range 0 to 3000 psi (RCM8 to 9000 psi), resolution 0.1% of range.
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Self balancing potentiometer which converts the output from each sensor into a 10 bit binary number for storage on magnetic tape.
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Associated electronics.
A built-in clock triggers the instrument at preset intervals and up to six channels are sampled in sequence. Channel 1 is a fixed reference reading for control purposes and data identification. Channels 2, 3 and 4 represent measurement of temperature, conductivity and pressure. Channels 5 and 6 represent the VECTOR AVERAGED current speed and direction since the previous triggering of the instrument. The number of rotor revolutions and the direction is sampled every 12 seconds and broken into North and East components. Successive components are added and recorded as speed and direction. For recording intervals longer than 10 minutes, speed and direction are sampled 1/50th of recording interval.
It has become common practice in some laboratories to deploy these meters as temperature and conductivity loggers without current measuring capabilities.
The following link will provide the manufacturer specifications:
Manufacturer specificationsBODC processing
The data were provided to BODC in two ASCII files, one for the instruments at the top of the mooring and one for the instruments at the bottom of the mooring. The files contained both current meter and hydrographic data. BODC split each file into two separate .mat files, separating the current and hydrographic data. At the same time the conductivity data was converted by dividing the values by 10.
The files provided contained two temperature readings, one labeled 'temperature RAW' and one 'Arctic temperature'. According to the originator only the Arctic temperature should be used as it is a much finer range with better resolution. It was therefore decided to only transfer the Arctic temperature values.
The four files were transferred to a format which is a subset of NETCDF by BODC generated Matlab script. During the transfer the originators variables were mapped to unique BODC parameter codes. The following table describes the mapping.
Original variable | Description | units | Parameter code | Units | Comments |
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speed | Current speed | m s-1 | LCSAEL01 | m s-1 | - |
direction | Current direction | Degrees True | LCDAZZ01 | Degrees True | - |
conductivity | Conductivity | S m-1 | CNDCPR01 | mS cm-1 | Values converted by applying a division of 10 |
Arctic temperature | Temperature | oC | TEMPPR01 | oC | - |
temperature RAW | Temperature | oC | - | - | Not transferred |
Screening
Following transfer the data were screened using the BODC generated in-house visualisation software, EDSERPLO. Data points that were considered suspect were marked with the appropriate data quality control flag. Absent data values were changed to an appropriate value and marked with the corresponding quality control flag.
Originator's processing
The mooring was deployed by streaming it out behind the ship, and dropping the anchor last. The mooring was recovered nine days later, and both rotors were broken. The lower positioned instrument RCM8S~5379 was accidentally deployed in 'momentary mode', where vector averaging is disabled, and all directions are therefore instantaneous measurements.
The instruments were set to sample at 5-minute intervals and both current meters logged throughout the deployment.
Project Information
AutoSub Under Ice (AUI) Programme
AutoSub was an interdisciplinary Natural Environment Research Council (NERC) thematic programme conceived to investigate the marine environment of floating ice shelves with a view to advancing the understanding of their role in the climate system.
The AUI programme had the following aims:
- To attain the programme's scientific objectives through an integrated programme based on interdisciplinary collaborations and an international perspective
- To develop a data management system for the archiving and collation of data collected by the programme, and to facilitate the eventual exploitation of this record by the community
- To provide high-quality training to develop national expertise in the use of autonomous vehicles in the collection of data from remote environments and the integration of such tools in wider programmes of research
- To stimulate and facilitate the parameterising of sub-ice shelf processes in climate models, and to further demonstrate the value of autonomous vehicles as platforms for data collection among the wider oceanographic and polar community
Following the invitation of outline bids and peer review of fully developed proposals, eight research threads were funded as part of AUI:
Physical Oceanography
- ISOTOPE: Ice Shelf Oceanography: Transports, Oxygen-18 and Physical Exchanges.
- Evolution and impact of Circumpolar Deep Water on the Antarctic continental shelf.
- Oceanographic conditions and processes beneath Ronne Ice Shelf (OPRIS).
Glaciology and Sea Ice
- Autosub investigation of ice sheet boundary conditions beneath Pine Island Glacier.
- Observations and modelling of coastal polynya and sea ice processes in the Arctic and Antarctic.
- Sea ice thickness distribution in the Bellingshausen Sea.
Geology and Geophysics
- Marine geological processes and sediments beneath floating ice shelves in Greenland and Antarctica: investigations using the Autosub AUV.
Biology
- Controls on marine benthic biodiversity and standing stock in ice-covered environments.
The National Oceanography Centre Southampton (NOCS) hosted the AUI programme with ten further institutions collaborating in the project. The project ran from April 2000 until the end of March 2005, with some extensions to projects beyond this date because of research cruise delays. The following cruises were the fieldwork component of the AUI project:
Table 1: Details of the RRS James Clark Ross AUI cruises.
Cruise No. | Cruise No. synonyms | Dates | Areas of study |
---|---|---|---|
JR20030218 | JR84 | 28 February 2003 to 4 April 2003 | Amundsen Sea, Antarctica |
JR20040813 | JR106, JR106a, JR106N (North) | 10 August 2004 to 30 August 2004 | Northeast Greenland Continental Shelf, Greenland |
JR20040830 | JR106b, JR106S (South) | 30 August 2004 to 16 September 2004 | Kangerlussuaq Fjord, Greenland |
JR20050203 | JR97, JR097 | 3 February 2005 to 11 March 2005 | Fimbul Ice Shelf and Weddell Sea, Antarctica . This cruise was redirected from the Filcner-Ronne Ice Shelf to the Fimbul Ice Shelf because of unfavourable sea-ice conditions. |
All the cruises utilised the AutoSub autonomous, unmanned and untethered underwater vehicle to collect observations beneath sea-ice and floating ice shelves. AutoSub can be fitted with a range of oceanographic sensors such as:
- Conductivity Temperature Depth (CTD) instruments
- Acoustic Doppler Current Profillers (ADCP)
- A water sampler
- Swath bathymetry systems
- Cameras
In addition to use of AutoSub during each cruise measurements were taken from ship. These varied by cruise but included:
- Ship underway measurements and sampling for parameters such as:
- Salinity
- Temperature
- Fluorescence
- Oxygen 18 isotope enrichment in water
- Bathymetry using a swath bathymetry system
- Full-depth CTD casts for with observations of samples taken for parameters such as:
- Salinity
- Temperature
- Fluorescence
- Optical transmissivity
- Dissolved oxygen
- Oxygen 18 isotope enrichment in water
- Water CFC content
- Sea floor photography and video using the WASP system
- Sea floor sampling with trawls/rock dredges
- Sea ice observations (ASPeCt), drifters and sampling
The AutoSub project also included numerical modelling work undertaken at University College London, UK.
The project included several firsts including the first along-track observations beneath an ice shelf using an autonomous underwater vehicle. The AutoSub vehicle was developed and enhanced throughout this programme and has now become part of the NERC equipment pool for general use by the scientific community. Further information for each cruise can be found in the respective cruise reports (links in Table 1).
Data Activity or Cruise Information
Data Activity
Start Date (yyyy-mm-dd) | 2005-02-12 |
End Date (yyyy-mm-dd) | 2005-02-21 |
Organization Undertaking Activity | British Antarctic Survey |
Country of Organization | United Kingdom |
Originator's Data Activity Identifier | Fimbul |
Platform Category | subsurface mooring |
Autosub Under Ice Fimbul Ice Shelf mooring
The mooring was deployed and recovered during James Clark Ross cruise 97 (JCR97) between 3rd February and 11th March 2005.
Mooring position | 70.115°N, 1.843°W |
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Water Depth | 355m |
Deployed | 12 February 2005 14:06 |
Recovered | 21 February 2005 13:40 |
The Fimbul mooring was anchored to the Sea bed by a 250 kg weight. A mooring diagram is available on page 120 of the cruise report, which is accessible through the JCR97 metadata report.
The following instruments were attached to the mooring.
Instrument | Height above Sea bed (meters) |
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Aandera Instruments Current Meter RCM8S#5379 | 20 |
Aandera Instruments Current Meter RCM8S#10067 | 140 |
Aandera Instruments DSU 2990#6820 | 20 |
Aandera Instruments DSU 2990#8825 | 140 |
Related Data Activity activities are detailed in Appendix 1
Cruise
Cruise Name | JR20050203 (JR97) |
Departure Date | 2005-02-03 |
Arrival Date | 2005-03-11 |
Principal Scientist(s) | Keith Nicholls (British Antarctic Survey) |
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 |
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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 |
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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 |
Appendix 1: Fimbul
Related series for this Data Activity are presented in the table below. Further information can be found by following the appropriate links.
If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.
Series Identifier | Data Category | Start date/time | Start position | Cruise |
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648791 | Currents -subsurface Eulerian | 2005-02-12 14:15:00 | 70.115 S, 1.8433 W | RRS James Clark Ross JR20050203 (JR97) |
648810 | Hydrography time series at depth | 2005-02-12 14:15:00 | 70.115 S, 1.8433 W | RRS James Clark Ross JR20050203 (JR97) |
648822 | Hydrography time series at depth | 2005-02-12 14:15:00 | 70.115 S, 1.8433 W | RRS James Clark Ross JR20050203 (JR97) |