Metadata Report for BODC Series Reference Number 969424

• 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

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

Teledyne RDI Workhorse Sentinel 600 kHz Acoustic Doppler Current Profiler (ADCP)

The Workhorse Sentinel is a self-contained ADCP that can be used either on a mooring or mounted in the hull of a moving vessel. Its 4-beam design provides a redundant data source (in case of a blocked or damaged beam), an independent data quality measure (error velocity) and reduces the variance in data, thereby improving data reliability, quality and accuracy.

Real-time data can be transmitted to shore via a cable link or acoustic modem or they can be stored internally. Sensors for bottom tracking, pressure and directional wave measurements can be added to the instrument and a special casing is available for deeper applications.

Specifications

Further details can be found in the manufacturer's specification sheet.

BODC 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 in ASCII format files. These series were reformatted to the internal QXF format using BODC transfer function 415. The following table shows how the variables within the file were mapped to the appropriate BODC parameter codes:

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

Data Activity

SIMORC Moored Instrument AHRCD#4

The nominal position of this deployment is 40.87467° N, 49.53333° E with a water depth of 25 m.

The instrument was installed on a sea bed frame on 18/09/2006 and was removed on 10/12/2006. This installation was set on behalf of TOTAL in Azerbaijan, Caspian Sea and consisted of the following series.

ASB =Above Sea Bed.

Related Data Activity activities are detailed in Appendix 1

Fixed Station Information

Fixed Station Information

SIMORC: TOTAL Azerbaijan Sharabad Offshore Fixed Station Document

Temperature, salinity sensors and tide gauge were deployed on a sea bed frame 5 times between 18/12/2005 and 21/03/2007 at this site.

The nominal position is 40.87527°N; 49.51677° E with a water depth of 25 m.

Data were collected by Fugro Geos on behalf of TOTAL from Sharabad fixed station as follows:

Where: HRCD = Moored hydrographical data, ADCP = Acoustic Doppler Current Meter.

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:

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

Appendix 1: AHRCD#4

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.

Appendix 2: Azerbaijan Sharabad offshore

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.