Metadata Report for BODC Series Reference Number 746042

• 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

SIMORC Data Quality Report: Angola Girassol CTD

The data are of good quality.

The CTD depth channel sometimes shows the CTD stopping during short times in accordance with the purpose of the CTD (to compare the temperature and conductivity data of the CTD to current meter data collected at the same time as the CTD data). These stop times are also evident in the temperature and conductivity channels.

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

Sea-Bird SBE 19 and SBE 19plus SEACAT Profiler CTDs

The SBE 19 SEACAT Profiler is a self-contained, battery powered, pumped CTD system designed to measure conductivity, temperature, and pressure in marine or fresh water environments to depths of 10,500 meters. It was replaced by the SBE 19plus model in 2001. An updated version of this instrument is the SBE 19plus V2, which incorporates an electronics upgrade and additional features, with six differentially amplified A/D input channels, one RS-232 data input channel, and 64 MB FLASH memory.

The standard CTD unit comes with a plastic housing (rated to 600 m), although this can be replaced by titanium housing for depths up to 7000 m. It is typically used for CTD profiling although a conversion kit is available for mooring deployments. The CTD can also be attached to an SBE 36 CTD Deck Unit and Power/Data Interface Module (PDIM) for real-time operation on single-core armored cable up to 10,000 m.

Specifications

*Measurements outside this range may be at slightly reduced accuracy due to extrapolation errors.

Options and accessories

Additional sensors can be attached to the CTD, including:

• high accuracy Paroscientific Digiquartz pressure sensor (depth range 0 to 20, 60, 130, 200, 270, 680, 1400, 2000, 4200, 7000 or 10500 m; accuracy 0.02% of full scale; resolution 0.0025% of full scale)
• Dissolved Oxygen (SBE 43 DO Sensor)
• pH* (SBE 18 pH Sensor or SBE 27 pH/ORP Sensor)
• fluorescence
• radiance (PAR)
• light transmission
• optical backscatter (turbidity)

The standard SBE 5M pump may be replaced by an SBE 5P (plastic housing) or 5T (titanium housing) pump for use with dissolved oxygen and/or other pumped sensors. Further details can be found in the manufacturer's SBE 19plus V2 instrument specification or theSBE 19 andSBE 19 plus user guides.

Sea-Bird SBE 16 SEACAT

The SBE 16 SEACAT designed to measure and record temperature and conductivity at high levels of accuracy while deployed in either a fixed or mooring application. Powered by internal batteries, SEACAT is capable of recording data for periods of a year or more. SEACAT's precision time-base is accurate to within 3 minutes per year. An internal battery back-up is used to support memory and the real time clock in the event of instrument failure or exhaustion of the main battery supply. Communication with SEACAT is over a 3 wire RS-232C link.

Specifications

Further information can be found via the following link: Official Sea-Bird Website

EEA Sea-Bird Seacat calibration information

The Sea-Bird Seacat was last calibrated in 25/07/1997. Calibration coefficients are stated below:

SBE S/N 195057-2391

Date: 26 March 1997

Pressure calibration: PAINE 211-36-730-02; 5000psia; S/N 180493

Temperature Compensation (TC) value = -141

Straight Line Fit:

Pressure (psia) - M + N + B ( N= Binary output)

M= -0.65014 B= 2546.40

Quadratic Fit:

Pressure (psia) - A0 + A1 * N + A2 * N * N (N = binary output)

A0 = 2546.67320 ; A1 = -6.501358 e-01 ; A2 = -3.959561 e-08

Output binary values are averages of 101 samples taken at 2 Hz. SEASOFT Versions 3.3M and higher will prompt for A0, A1, and A2. SEASOFT Versions 3.3L and lower will prompt for M and B.

SEA-BIRD ELECTRONICS, INC;

1808 136th Place N.E., Bellevue, Wachington 98005 USA; Phone: (206) 643 - 9866, Fax: (206) 643 - 9954, Internet : seabird@seabird.com;

SENSOR SERIAL NUMBER = 2391; CALIBRATION DATE = 25-Jul-97s;

TEMPERATURE CALIBRATION DATA: ITS-90 TEMPERATURE SCALE

Temperature ITS-90 = 1/{g + h[ln(f0/f)] +i[ln²(f0/f)] +j[ln³(f0/f)]} - 273.15 (°C)

Temperature IPTS-68 = 1/{a + b[ln(f0/f)] +c[ln²(f0/f)] +d[ln³(f0/f)]} - 273.15 (°C)

Following the recommandation of JPOTS: T68 is assumed to be 1.00024 * T90 (-2 to 35 °C)

Residual = instrument temperature - bath temperature.

SEA-BIRD ELECTRONICS, INC

1808 136th Place N.E., Bellevue, Wachington 98005 USA; Phone: (206) 643 - 9866, Fax: (206) 643 - 9954, Internet : seabird@seabird.com

SENSOR SERIAL NUMBER = 2391; CALIBRATION DATE = 25-Jul-97s;

CONDUCTIVITY CALIBRATION DATA: PSS 1978: C(35,15,0) = 4.2914 Siemens/meter

Conductivity = (g + hf ² + if ² +jf ⁴) / [10(1 + CTcor*t + CPcor*p)] Siemens/meter

Conductivity = (af ^m + bf ² + c + dt) / [10(1 + CPcor)] Siemens/meter

t = temperature [deg C]; p = pressure [decibar];

Residual = (instrument conductivity - bath conductivity) using g, h, i, j coefficients.

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

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.

ELF EXPLORATION ANGOLA, Girassol, Deep Water Current Measurements

Period: September 1997 - October 1998.

The goal of this was to observe and characterize the nature of the current regime in this area. This study is a preliminary to the riser design for the Girassol field production well (2 km east from the mooring position).

This deployment was divided into five phases, to allow approximately 75 day intervals between visits for data retrieval and equipment maintenance.

Data Activity or Cruise Information

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

SIMORC: Total Angola, Block 17 Girassol, Fixed Station Document

This site is part of the Total facility.

The moorings deployed lie within a box bounded by co-ordinates 7.7° S, 11.65° E at the southwest corner and 7.67° S, 11.6825° E at the northeast corner.

The GIRASSOL platform, Block 17, offshore Angola consists of a Floating Production, Storage and Offloading vessel (FPSO) and a Single Buoy Mooring (SBM).

Various deployments were taken from or near this station over a number of years.

Between September 1997 and October 1998

A current meter mooring occupied this site. In addition to time series data obtained from the moored instruments, CTD profiles were conducted following the deployment and prior to the recovery of the mooring to be used for calibration purposes.

Between March 2001 and July 2004

Wind, current and wave data have been collected on behalf of Total on the Girassol field.

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: ANGOLA GIRASSOL

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.