Metadata Report for BODC Series Reference Number 1738377
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
Data Description |
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Data Identifiers |
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Time Co-ordinates(UT) |
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Spatial Co-ordinates | |||||||||||||||||||||||||||||||||
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Parameters |
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Problem Reports
No Problem Report Found in the Database
Data Access Policy
SIMORC data access conditions
The data collated and held at BODC on behalf of the SIMORC project are restricted. However, the data will be available to download from the Official SIMORC Website, as part of the project protocol. The data set will initially include data from the oil companies TOTAL, Shell and BP.
Narrative Documents
RBR XR-420 CTD
The XR-420 CTD Marine is a small, autonomous conductivity, temperature and depth recorder, from which high accuracy speed of sound and salinity can be derived. Its titanium housing provides a depth rating for the cell of 6,600m which can be axial to the logger, whilst also providing shielding and stable cell geometry. The normal marine conductivity range of 0 to 70 mS/cm is measured by an inductive cell to an accuracy of ±0.003 mS/cm and with a response time of less than 95 milliseconds when profiling. It uses a three-coil system with a closed loop feedback for superior temperature compensation. 8MB of nonvolatile flash memory allows for 2, 400, 000 readings which can be logged on one set of high-powered 3V lithium batteries
Specifications
Temperature (°C) | Conductivity (S/m) | Optional Pressure | |
---|---|---|---|
Measurement Range | -5 to +35 | 0 to 7 (0 to 70 mS/cm) | 0 to full scale range: 10/25/60/150/250/740/1000/2000/ 3000/4000/6600 metres (dBar) |
Accuracy | ± 0.002 °C | ± 0.003 mS/cm | ± 0.05% full scale |
Resolution | <0.00005 °C | <0.0001 mS/cm | <0.001% full scale |
Communications | RS-232/485; logged, cable, or telemetry | ||
Download Speed | ~115,000 samples/minute | ||
Memory | 8Mbyte nonvolatile flash (2,400,000 samples) | ||
Sample Rate | 1Hz* to 24 hours (programmable) | ||
Clock Accuracy | ± 32 seconds/year | ||
Power | QTY 4, 3V CR123A cells. | ||
Housing | Depth rating of the cell of up to 6,600m | ||
Size | 400mm x 64mm | ||
Weight of plastic (without pressure) | In water: 0.389Kg In air: 1.259Kg | ||
Calibration | NIST traceable standards |
Further information can be found on the Official RBR Website or in the manufacturer's specification sheet.
BODC CTD Screening
BODC screen both the series header qualifying information and the parameter values in the data cycles themselves.
Header information is inspected for:
- Irregularities such as infeasible values
- Inconsistencies between related information. For example:
- Deepest CTD data cycle is significantly greater than the depth of the sea floor.
- Times of the cruise and the start/end of the data series.
- Length of the record, number of data cycles, cycle interval, clock error and the period over which data were collected.
- Parameters stated as measured and the parameters actually present in the data series.
- Originator's comments on instrument/sampling device performance and data quality.
Documents are written by BODC highlighting irregularities that cannot be resolved.
Data cycles are inspected using depth series plots of all parameters. These presentations undergo screening to detect infeasible values within the data cycles themselves and inconsistencies when comparing adjacent data sets displaced with respect to depth, position or time.
Values suspected of being of non-oceanographic origin may be tagged with the BODC flag denoting suspect value.
The following types of irregularity, each relying on visual detection in the time series plot, are amongst those that may be flagged as suspect:
- Spurious data at the start or end of the record where the instrument was recording in air
- Obvious spikes occurring in the data due electrical problems
- Constant, or near-constant, data channels
If a large percentage of the data is affected by irregularities, deemed abnormal, then instead of flagging the individual suspect values, a caution may be documented.
The following types of inconsistency are detected automatically by software:
- Data points with values outside the expected range for the parameter, as defined by the BODC parameter usage vocabulary.
Inconsistencies between the characteristics of the data set and those of its neighbours are sought, and where necessary, documented. This covers inconsistencies in the following:
- Maximum and minimum values of parameters (spikes excluded).
- Anomalous readings due to the CTD package being bounced through temperature and/or salinity gradients.
This screening of the parameter values seeks to confirm the qualifying information and the source laboratory's comments on the series. In screening and collating information, every care is taken to ensure that errors of BODC's making are not introduced.
BODC Processing
Data were received by BODC in Excel spreadsheets and converted into CSV before reformatting to QXF format using BODC transfer function 518. The following table shows how the variables within the files were mapped to the appropriate BODC parameter codes:
Original parameter name | Original Units | Description | BODC Parameter Code | BODC Units | Comments |
---|---|---|---|---|---|
Time | DD-MON-YY hh:mm:ss | Date and time | AADYAA01 + AAFDZZ01 | Day number and day fraction (GMT) | |
TEMP | degrees Celsius | Sea temperature | TEMPST01 | degrees Celsius | |
Depth(m) | metres | Instrument depth | DEPHPR01 | metres | |
Salinity | PSU | Salinity | PSALST01 | PSU | |
Turbid | Nephelometric Turbidity Units | Turbidity | TURBXXXX | Nephelometric Turbidity Units | |
Conductivity | milliSiemens/centimetre | Conductivity | CNDCST01 | Siemens/metre | /10 |
SoS | metres/second | Speed of sound in seawater | SVELCT01 | metres/second |
Following transfer to QXF, the data were screened using BODC's in-house visualisation software, EDSERPLO.
Project Information
System of Industry Metocean data for the Offshore and Research Communities (SIMORC)
The EU-funded SIMORC project is a collaborative effort between MARIS (Netherlands), BODC (UK), the International Association of Oil and Gas Producers (OGP) and IOC-IODE to provide a harmonised and quality controlled metocean data set from data collected by oil and gas producers, accessible through the SIMORC protocol.
Data Activity or Cruise Information
Cruise
Cruise Name | Tartaruga 20091201 |
Departure Date | 2009-12-01 |
Arrival Date | 2009-12-12 |
Principal Scientist(s) | Paul Trapier Puckette (Evans-Hamilton, Inc) |
Ship | Unknown unknown |
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 |