Metadata Report for BODC Series Reference Number 424958

• 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

Open 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.

If the Information Provider does not provide a specific attribution statement, or if you are using Information from several Information Providers and multiple attributions are not practical in your product or application, you may consider using the following:

"Contains public sector information licensed under the Open Government Licence v1.0."

Narrative Documents

West Bexington PWR Data Collection (1987-1995)

Data was recorded at this site on HP magnetic tape until the end of 1989. The system processed the data from 2048 readings taken every second at 90 minute intervals. The spectrum was computed and averaged over 20 estimates to give 48 averages in a frequency range from 0.025 Hz to 0.484 Hz. Eight tide heights averaged over 256 seconds each were also computed from the pressure signal. The wave spectrum was corrected for depth attenuation. These data and other housekeeping data were stored in an array dimensioned as data(96) and stored on magnetic tape using 768 bytes per record.

From day 99 in 1990 the logging system was changed to record on EPROM cards and the processing system was also modified. From this date the system processed data from 1024 readings taken every second at 18 minute intervals. The spectrum was computed and averaged over 10 estimates to give 48 averages for a frequency range from 0.025 Hz to 0.0484 Hz. Four tide heights averaged over 256 seconds each were also computed from the pressure signal. The wave spectrum was corrected for depth attenuation. These data and other housekeeping data, including from this date the calibration and frequency offset, were stored in an array dimensioned as data(96). These data were routinely recorded every 90 minutes, and additionally at the 18 minute sample interval if Hs exceeded 2.5 metres. These data were recorded on EPROM card as strings of length 288 bytes and 6 identity bytes.

Temperature drift of the transducer and variations in atmospheric pressure have been eliminated in post processing by using a filter which corrected the mean depth to a constant value when averaged over 48 hours.

Files from 1988 to 1990 day 99 have been replayed using a mean depth of 10.0 metres.

Files from 1990 day 99 to 1992 day 80 have been replayed using a mean depth of 10.5 metres.

Files from 1993 day 66 to 1994 day 365 have been replayed using a mean depth of 11.0 metres.

The different depths were required because the transducers were replaced on the sea bed in slightly different positions and hence water depth.

General Data Screening carried out by BODC

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:
  • Times for instrument deployment and for start/end of data series
  • Length of record and the number of data cycles/cycle interval
  • Parameters expected 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 or depth 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 data values will not be altered.

The following types of irregularity, each relying on visual detection in the 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 then a Problem Report will be written rather than flagging the individual suspect values. Problem Reports are also used to highlight irregularities seen in the graphical data presentations.

Inconsistencies between the characteristics of the data set and those of its neighbours are sought and, where necessary, documented. This covers inconsistencies such as the following:

• Maximum and minimum values of parameters (spikes excluded).
• The occurrence of meteorological events.

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.

Project Information

MAFF Wave-Model Comparison

In order to validate and improve operational wave predictions from the Meteorological Office Fine Mesh Wave Model, wave measurements were made at inshore and offshore sites at three UK locations (Lyme Bay, Mablethorpe off the Lincolnshire Coast and Morecambe Bay).

BODC hold the wave measurements made at these six sites and the associated model output. The Marine Advisory Service (Commercial Services), of the Meteorological Office should be contacted regarding model output availability.

Data Activity or Cruise Information

No Data Activity or Cruise Information held for the Series

Fixed Station Information

Fixed Station Information

West Bexington (1983-1993)

1-D spectral wave data were collected between 1983 and 1993. Two waverider deployments (sometimes referred to as West Bexington (a) and West Bexington (b)) covered the period between November 1983 and April 1988. A pressure wave recorder installation operated between December 1987 and May 1995. All instruments were located within 0.05 degrees of the nominal station position.

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:

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: West Bexington (1983-1995)

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.