Metadata Report for BODC Series Reference Number 962658
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
SIMORC Data Quality Report Total Angola Block 32, Louro long mooring
Narrative
This long mooring forms the observations made in Angola Block 32, Louro.
Data Quality Information
This data quality report refers only to the Aanderaa RCM7 and RCM8 current meters on this mooring. The acoustic Aanderaa SEAGUARD RCM was not affected. A significant data gap was observed from 08:50 on 21st April 2009 to 13:20 on 23rd April 2009. After this gap, the RCM7 and RCM8 current meters seemed to have been reset slightly in that zero current speeds were recorded as 1.1 cm/sec. Prior to the gap, these had been recorded as speeds of zero cm/sec. Periods in excess of 30 minutes where speeds remained stuck at 1.1 cm/sec were flagged suspect.
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
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 Current Meter 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 unfeasible values
- Inconsistencies between related information. For example:
- Depths of meter and sea bed.
- Times for mooring deployment and for start/end of data series.
- Length of record or number of data cycles, the cycle interval, the clock error and the period over which accrued.
- Parameters stated as measured and the parameters actually present in the data cycles.
- Originator's comments on meter/mooring performance and data quality.
Documents are written by BODC highlighting irregularities which cannot be resolved.
Data cycles are inspected using time series plots of all parameters. Currents are additionally inspected using vector scatter plots and time series plots of North and East velocity components. These presentations undergo intrinsic and extrinsic screening to detect infeasible values within the data cycles themselves and inconsistencies as seen when comparing characteristics of 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 which may be flagged as suspect:
- Spurious data at the start or end of the record.
- Obvious spikes occurring in periods free from meteorological disturbance.
- A sequence of constant values in consecutive data cycles.
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. Likewise documents will highlight irregularities seen in the current vector scatter plots such as incongruous centre holes, evidence of mooring 'knock-down', abnormal asymmetry in tidally dominated records or gaps as when a range of speeds or directions go unregistered due to meter malfunction.
The term 'knock-down' refers to the situation when the 'drag' exerted on a mooring at high current speeds may cause instruments to tilt beyond the angle at which they are intended to operate. At this point the efficiency of the current sensors to accurately record the flow is reduced.
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).
- The orientation and symmetry of the current vector scatter plot.
- The direction of rotation of the current vectors.
- The approximate amplitude and periodicity of the tidal currents.
- The occurrence of meteorological events and, finally, for series for which no time check was possible, the phase.
This intrinsic and extrinsic 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 making are not introduced.
BODC Processing
Data were received by BODC in ASCII format files (Fugro format). They were reformatted to QXF format using BODC transfer function 400. 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 |
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Time | DD-MON-YY hh:mm:ss | Date and time (GMT) | AADYAA01 + AAFDZZ01 | Day number and day fraction (GMT) | |
Curr_Speed | m/s | Speed | LCSAEL01 | cm/sec | *100 |
Curr_Direction | degrees True | Direction | LCDAEL01 | degrees True | |
Temp | degrees Celsius | Sea temperature | TEMPPR01 | degrees Celsius | |
Salinity | PSU | Salinity | PSALPR01 | PSU |
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
Data Activity
Start Date (yyyy-mm-dd) | 2009-01-17 |
End Date (yyyy-mm-dd) | 2009-07-25 |
Organization Undertaking Activity | Total S.A. |
Country of Organization | France |
Originator's Data Activity Identifier | Louro |
Platform Category | subsurface mooring |
SIMORC Total Louro Current Meter and ADCP mooring.
The survey at this site was made up of a single mooring.
This long mooring was deployed in a water depth of 1832 metres. (Nominal position of 7.504°S 11.2342°E):
Meter No. | Instrument Depth (m) | Instrument Type | Total Time Period | Comments |
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9771 | 41.2 | RDI 300kHz ADCP | 16-JAN-2009 TO 26-JUL-2009 | Upward-looking. |
677 | 42.7 | SeaBird SBE37 | 16-JAN-2009 TO 26-JUL-2009 | |
11520 | 446.1 | RDI 75kHz ADCP | 16-JAN-2009 TO 26-JUL-2009 | Upward-looking. |
288 | 446.1 | SeaBird SBE39 | 16-JAN-2009 TO 26-JUL-2009 | |
12497 | 696.2 | RCM7 | 16-JAN-2009 TO 26-JUL-2009 | |
11534 | 946.2 | RCM8 | 16-JAN-2009 TO 26-JUL-2009 | |
12474 | 1196.2 | RCM8 | 16-JAN-2009 TO 26-JUL-2009 | |
10050 | 1446.2 | RCM8 | 16-JAN-2009 TO 26-JUL-2009 | |
11260 | 1696.2 | RCM8 | 16-JAN-2009 TO 26-JUL-2009 | |
102 | 1822 | Aanderaa Seaguard | 16-JAN-2009 TO 26-JUL-2009 | with Aanderaa WLR8 |
Related Data Activity activities are detailed in Appendix 1
Cruise
Cruise Name | Seabulk Luanda 2009 |
Departure Date | 2009-01-14 |
Arrival Date | 2009-01-19 |
Principal Scientist(s) | |
Ship | Seabulk Luanda |
Complete Cruise Metadata Report is available here
Fixed Station Information
Fixed Station Information
Station Name | Louro, Angola Block 32 |
Category | Offshore location |
Latitude | 7° 30.24' S |
Longitude | 11° 14.05' E |
Water depth below MSL | 1832.0 m |
Total - Angola Block 32 - Louro
Latitude | Longitude | Water depth (m) |
---|---|---|
7.504°S | 11.23417°E | 1829 |
This fixed station is in Block 32, offshore Angola. A mooring was deployed at this site in January 2009 to cover a 12-month period of measurements of currents through the water column. Prior to the mooring deployment, a CTD dip was undertaken to check the actual water depth.
Related Fixed Station activities are detailed in Appendix 2
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: Louro
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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1052455 | Offshore sea floor pressure series | 2009-01-17 11:50:00 | 7.504 S, 11.23417 E | Petrogas Supply 1 Petrogas1 |
962449 | Currents -subsurface Eulerian | 2009-01-17 12:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
962450 | Currents -subsurface Eulerian | 2009-01-17 12:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
962610 | Currents -subsurface Eulerian | 2009-01-17 12:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
962622 | Currents -subsurface Eulerian | 2009-01-17 12:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
962634 | Currents -subsurface Eulerian | 2009-01-17 12:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
962646 | Currents -subsurface Eulerian | 2009-01-17 12:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
962671 | Currents -subsurface Eulerian | 2009-01-17 12:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
963397 | Hydrography time series at depth | 2009-01-17 12:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
963385 | Hydrography time series at depth | 2009-01-17 12:10:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
Appendix 2: Louro, Angola Block 32
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 |
---|---|---|---|---|
963428 | CTD or STD cast | 2009-01-17 11:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
1052455 | Offshore sea floor pressure series | 2009-01-17 11:50:00 | 7.504 S, 11.23417 E | Petrogas Supply 1 Petrogas1 |
962449 | Currents -subsurface Eulerian | 2009-01-17 12:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
962450 | Currents -subsurface Eulerian | 2009-01-17 12:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
962610 | Currents -subsurface Eulerian | 2009-01-17 12:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
962622 | Currents -subsurface Eulerian | 2009-01-17 12:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
962634 | Currents -subsurface Eulerian | 2009-01-17 12:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
962646 | Currents -subsurface Eulerian | 2009-01-17 12:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
962671 | Currents -subsurface Eulerian | 2009-01-17 12:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
963397 | Hydrography time series at depth | 2009-01-17 12:00:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
963385 | Hydrography time series at depth | 2009-01-17 12:10:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
963441 | CTD or STD cast | 2009-07-25 10:40:00 | 7.504 S, 11.2342 E | Seabulk Luanda Seabulk Luanda 2009 |
1095191 | CTD or STD cast | 2009-07-31 20:32:00 | 7.43115 S, 11.37261 E | Not applicable |
1095178 | CTD or STD cast | 2009-08-01 07:18:00 | 7.48931 S, 11.21687 E | Not applicable |
1095166 | CTD or STD cast | 2009-08-01 09:30:00 | 7.51441 S, 11.22179 E | Not applicable |
1095209 | CTD or STD cast | 2009-08-01 12:47:00 | 7.50099 S, 11.26061 E | Not applicable |