Metadata Report for BODC Series Reference Number 934798
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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Time Co-ordinates(UT) |
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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
Instrument description
Valeport 600 MKIII CTD
The Model 600 MKIII measures Conductivity, Temperature and Pressure parameters and has both time and depth increment based sampling. From these measurements Salinity, Density and Speed of Sound are calculated and displayed or recorded.
Specifications
Temperature
Thermistor range: -5 to 35 °C ; precision: +/- 0.1 °C
Conductivity
Inductive coils range: 0.1 to 60 mS.cm-1; precision: +/- 0.05 mS.cm-1
Pressure
Strain gauge range: 50,100, 500,1000 or 2000 dBar; precision: +/-0.5%
Manufacturer specifications can be found here
Valeport CTD 600
Background
The Valeport CTD 600 is designed for Continental Shelf operation and permits the accurate measurement of seawater Conductivity and Temperature against a Depth profile. The results obtained are applicable to many fields of scientific research. The meter is particularly suited to the obtaining of Temperature and Salinity profiles for the computation of the Speed of Sound through water, as required for the calibration of survey echo sounders and acoustic navigation systems.
More information may be found:
Click here for an Oceanscan instrument description
Click here for a pdf stored by BODC.
Parameters
Parameter | Sensor Type | Operating Range | Accuracy | Display Resolution | Response Time |
---|---|---|---|---|---|
Conductivity | Dual inductive coils | 0 - 60 mmho cm-1 | Better than 0.2 mmho cm-1 | 0.01 mmho cm-1 | - |
Temperature | Linearised Thermistor | -5 to +40 °C | Better than 0.2 °C | 0.01 °C | < 3 secs to 98% |
Pressure | Strain gauge pressure transducer | 0 to 10, or 0 to 20 bar standard, (100 or 200 m) Optional, 0 to 50 bar (500 m) Note, 10 bar fitted in units with 50 m cables | +/- 0.3% of full scale | 0.1 m | - |
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
The originator provided a Comma Separated Values format file. This series was reformatted to the internal QXF format using BODC transfer function 422. The following table shows how the variables within the file were mapped to the appropriate BODC parameter codes:
Original parameter name | Original Units | Description | BODC Parameter Code | BODC Units | Comments |
---|---|---|---|---|---|
Time | DD/MM/YYYY HH:MI | date and time | AADYAA01 + AAFDZZ01 | day number and day fraction GMT | Conversion by transfer |
SoundSpeed | m.s-1 | Sound velocity | SVELCT01 | m.s-1 | |
Depth | m | DEPHPR01 | m | ||
Temperature | degrees Celsius | TEMPST01 | degrees Celsius | ||
Conductivity | S.cm-1 | CNDCST01 | S.m-1 | Conversion (RAW *0.1) by transfer | |
Pressure | decibars | PRESPR01 | decibars | ||
Salinity | psu | PSALST01 | psu |
Datacycles from the up cast were deleted as only the down cast was transferred.
Following transfer to QXF, the data were screened using BODC's in-house visualisation software, EDSERPLO. Any data considered as suspect were flagged 'M'.
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 | 2001 1/4 |
Departure Date | 2001-01-07 |
Arrival Date | 2001-01-07 |
Principal Scientist(s) | Unknown (United Kingdom Ocean Research Services) |
Ship | Sea Trident |
Complete Cruise Metadata Report is available here
Fixed Station Information
Fixed Station Information
Station Name | Nigeria OML100 |
Category | Offshore location |
Latitude | 3° 52.66' N |
Longitude | 7° 55.12' E |
Water depth below MSL | 100.0 m |
SIMORC: TOTAL Nigeria OML100 Fixed Station Document
5 CTD casts were taken from 07/01/2001 to 18/07/2002 at this site.
The nominal position of the instrument is 3.877585° N; 7.918625° E with a water depth of 100 m.
CTD casts were done on behalf of TOTAL from Nigeria OML100 fixed station as follows:
Cruise inventory name | Instrument | Start Date | Comments |
---|---|---|---|
MV Norwich Service 1/4 | VALEPORT USPC 0014 | 07/01/2001 22:27:00 | |
MV Norwich Service 2/4 | VALEPORT USPC 0014 | 09/01/2001 22:27:00 | |
MV Norwich Service 3/4 | VALEPORT USPC 0014 | 11/01/2001 20:39:00 | |
MV Norwich Service 4/4 | VALEPORT USPC 0014 | 15/01/2001 05:58:00 | |
VALEPORT 600 CTD | 18/07/2002 18:28:09 |
Related Fixed Station activities are detailed in Appendix 1
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 |
Appendix 1: Nigeria OML100
Related series for this Fixed Station 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 |
---|---|---|---|---|
934805 | CTD or STD cast | 2001-01-09 22:27:00 | 3.88703 N, 7.92913 E | Sea Trident 2001 2/4 |
934817 | CTD or STD cast | 2001-01-11 20:39:00 | 3.89425 N, 7.90347 E | Sea Trident 2001 3/4 |
934829 | CTD or STD cast | 2001-01-15 05:58:00 | 3.89012 N, 7.93378 E | Sea Trident 2001 4/4 |
934830 | CTD or STD cast | 2002-07-18 18:28:00 | 3.85 N, 7.93333 E | Sea Trident 1/1 |