Metadata Report for BODC Series Reference Number 1844138
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
No Problem Report Found in the Database
XBT data from cruise JR17001 Quality Report
Screening and Quality Control
During BODC quality control, data were screened using in house visualisation software. The data were screened and any obvious outliers and spikes were looked at in closer detail and flagged if necessary.
All values logged below the seabed maximum depth or the maximum depth of the XBT probe were flagged M as are considered improbable. The seabed depth was determined by cross checking against the General Bathymetric Chart of the Oceans (GEBCO), the raw cruise swath bathymetry and single beam echosounder data. This occurred in the following series:
- series 1844095 - flagged from cycle 2716 to end
- series 1844102 - flagged from cycle 165 to end
- series 1844114 - flagged from cycle 671 to end
- series 1844126 - flagged from cycle 489 to end
- series 1844138 - flagged from cycle 710 to end
- series 1844151 - flagged from cycle 681 to end
- series 1844175 - flagged from cycle 687 to end
Data Access Policy
Public domain 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.
The recommended acknowledgment is
"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."
Narrative Documents
Lockhead Martin T7 XBT probe
The XBT's deployed on this cruise were orignally manufactured by Sippican, which was acquired by Lockhead Martin sometime after this cruise ended.
An XBT probe is an expendable free-fall temperature probe that provides a profile of measured temperature against depth calculated from a fall-rate model. The T-7 XBT Probe can be used within a maximum depth of 760m, may be deployed at a ship speed of up to 15 knots and has a vertical resolution of 65cm.
Further details can be found in the manufacturer's specification sheet.
BODC Data Processing of XBT data from cruise JR17001
Data Processing
The XBT data from cruise JR17001 were submitted to BODC in .edf format, which can be opened in a text editor. The .edf files contain resistance, depth, temperature and sound velocity data. The files also include the following metadata stored in the header: deployment time, latitude, longitude, probe type, terminal depth, depth coefficients and constant salinity value used to derive sound velocity. The files were archived and transferred to BODC internal format using standard BODC processing procedures. However, only eight of the 12 submitted deployments were transferred due to four files relating to failed deployments. The variables provided in the files were mapped to BODC parameter codes as follows:
| Originator's Variable | Originator's Units | BODC Parameter Code | BODC Units | Comment |
|---|---|---|---|---|
| Resistance | ohms | - | - | Channel not transferred but is available on request. |
| Depth | m | DEPHCV01 | m | - |
| Temperature | °C | TEMPET01 | °C | - |
| Sound Velocity | m s-1 | SVELCV01 | cm s-1 | - |
Screening
Post transfer analysis and crosschecks were applied according to BODC procedures. This involved the screening of data using BODC's in house visualisation software where any improbable data were flagged but not removed.
Originator Data Processing of XBT data from cruise JR17001
Sampling Strategy
There were 12 Expendable Bathythermographs (XBTs) deployments during cruise JR17001 using either a Lockheed Martin Sippican T-5 XBT probe or Lockheed Martin Sippican T-7 XBT probe. T-7 XBT probes were deployed during the multibeam mapping components of the cruise to provide sound velocity profile corrections for the EM122 data. Winch failure prevented the completion of CTD casts in Drake Passage and so XBTs (both T-5 and T-7 models) were deployed to obtain the remaining temperature profiles for the northern stations.
Data Processing
The data were saved as .edf files (ASCII output of profile data and launch metadata in the header) and .rdf files for each deployment with no further processing.
Issues Encountered
XBT deployments 6 to 9 logged erroneous data prior to launch. It was initially suspected to be due to operator error as the XBT was loaded 20 minutes prior to arriving on station however launching a new XBT immediately after loading still resulted in errors. The AME electrical engineer then cleaned the contacts and rebooted the system but the problem still persisted. The fault was discovered to be flooding of the connector on both the deck and launcher, once these connectors had been replaced the XBT resumed launching successfully.
Project Information
Impacts of deglaciation on benthic marine ecosystems in Antarctica
Impacts of deglaciation on benthic marine ecosystems in Antarctica (ICEBERGS) is one of three NERC-CONICYT joint funded projects running from 2017 to 2021. The aim of the programme is to investigate the impacts of physical disturbance arising from climate-warming induced deglaciation on benthic communities around the West Antarctic Peninsula.
Participants
There are four research institutions involved in the project:
- University of Bangor
- University of Exeter
- Universidad Católica de la Santísima Concepción
- British Antarctic Survey (BAS)
Research Details
In order to meet the aim of the project, the ICEBERGS consortium produced six objectives:
- Monitoring glacier retreat over time and scour intensity on the adjacent seabed.
- Determine the benthic assemblage structure from localities with different perturbation levels.
- Evaluate nutritional and reproductive conditions of adults.
- Analyse growth rates from bivalve/gastropod shells and bryozoan populations with different perturbation levels.
- Develop reconstructions of physical disturbance due to iceberg discharge from growth patterns present in the carbonate structure of the shells of marine molluscs.
- Estimate the effect of marine glacier discharge and iceberg scouring on the genetic diversity and connectivity of marine invertebrate populations and the role of dispersal potential.
Fieldwork and Data Collection
The fieldwork for the project consists of research cruises along the west Antarctic Peninsula across three field seasons on board the RRS James Clark Ross. Three sites (Marine Cove, William Glacier and Sheldon Glacier) were selected for the fieldwork using available bathymetry and glacier retreat data. The fieldwork covers physical oceanography, marine geology, habitat mapping, community structure and seabed sediments and consists of CTD deployments, multi-beam swath bathymetry surveys, TOPAS sub-bottom profiling, shallow underwater camera system deployments, plankton net deployments, Agassiz trawls, Hamon grabs and multi-corer deployments.
Data Activity or Cruise Information
Cruise
| Cruise Name | JR17001 (ORCHESTRA) |
| Departure Date | 2017-11-21 |
| Arrival Date | 2017-12-21 |
| Principal Scientist(s) | David Barnes (British Antarctic Survey), J Alexander Brearley (British Antarctic Survey), Yvonne L Firing (National Oceanography Centre, Southampton) |
| 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 |
