Metadata Report for BODC Series Reference Number 1034657

• 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

FRV Scotia 0709S part b Data quality report

The attenuation and chlorophyll channels contain a significant proportion of noisy data.

These data should be used with caution.

Data Access Policy

Public domain 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.

The recommended acknowledgment is

"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."

Narrative Documents

Instrument Description

CTD Unit and Auxiliary Sensors

A Sea-Bird Electronics SBE 25 Sealogger CTD unit was used. Water samples were collected with a SBE 35 Carousel, which was attached to the CTD frame. The CTD unit included the following sensors.

Sea-Bird SBE 25 SEALOGGER CTD

The SBE 25 SEALOGGER is a research-quality CTD profiling system used for coastal, estuarine and, can also be a practical option, for deep-water work. It is easily configured in the field for a wide range of auxiliary sensors. The SEALOGGER is self-powered, requires no conductive cable, and is designed for use up to 6800 meters (10,000 psia). It uses the SBE3F temperature and SBE4 conductivity sensors as well as having an external strain gauge pressure sensor. It provides pump-controlled T-C ducted flow, samples at 8 Hz, records internally and provides simultaneous real-time data via its built-in RS-232 interface.

The standard CTD unit comes with a plastic housing (rated to 600 m), although this can be replaced by aluminium housing for depths up to 6800 m.

Specifications

Options and accessories

Additional sensors can be attached to the CTD, including:

• 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 SBE 5T titanium pump can be used in place of SBE 5P pump. Further details can be found in the manufacturer's SBE 25 instrument specification.

WETLabs ECO FLNTU fluorescence and turbidity sensor

The Environmental Characterization Optics (ECO) Fluorometer and Turbidity (FLNTU) sensor is a dual wavelength, single-angle instrument that simultaneously determines chlorophyll fluorescence and turbidity. It is easily integrated in CTD packages and provides a reliable turbidity measurement that is not affected by Colored Dissolved Organic Matter (CDOM) concentration.

The FLNTU can operate continuously or periodically and has two different types of connectors to output the data. There are 5 other models that operate the same way as this instrument but have slight differences, as stated below:

• FLNTU(RT) - has an analog an RS-232 serial output and operates continuously, when power is supplied
• FLNTU(RT)D - similar to the FLNTU(RT) but has a depth rating of 6000 m
• FLNTUB - has internal batteries for autonomous operation
• FLNTUS - has an integrated anti-fouling bio-wiper
• FLNTUSB - has the same characteristics as the FLNTUS but with internal batteries for autonomous operation

Specifications

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

WETLabs C-Star transmissometer

This instrument is designed to measure beam transmittance by submersion or with an optional flow tube for pumped applications. It can be used in profiles, moorings or as part of an underway system.

Two models are available, a 25 cm pathlength, which can be built in aluminum or co-polymer, and a 10 cm pathlength with a plastic housing. Both have an analog output, but a digital model is also available.

This instrument has been updated to provide a high resolution RS232 data output, while maintaining the same design and characteristics.

Specifications

Further details are available in the manufacturer's specification sheet or user guide.

BODC Processing

Data were received by BODC in one ASCII format file that was subsequently split into 119 separate files, one for each CTD profile. The series were reformatted to the internal QXF format using BODC transfer function 340. Sample calibrations were applied to the conductivity data. The following table details mapping of variables to 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. Flags from the originator marking suspect data were retained during transfer.

Originator's Data Processing

Sampling Strategy

A total of 119 CTD casts were performed on FRV Scotia cruise 0709S part b (21 May 2009 - 01 June 2009) at locations along the shelf edge to the north and west of Scotland. The data were collected between 03:38 hours on 21 May 2009 and 11:07 hours on 01 June 2009.

Water samples were collected in order to obtain independent salinity and fluoresence measurements. The sample data were used to derive calibrations for the conductivity and fluoresence profiles collected by the CTD.

Data Processing

The raw CTD data files were processed through the SeaBird Electronics SeaSoft data processing software following standard procedures. The originators used in-house interactive visual display editing software to edit out individual spikes in the primary temperature and conductivity channels. In addition, a low-pass filter (Sy 1985) was applied to particularly noisy data. An ASCII file was generated for each CTD cast and all files from a cruise were concatenated into one ASCII file which was submitted to BODC.

Sy A., 1985. An alternative editing technique for oceanographic data. Deep Sea Research Part A: Oceanographic Research Papers, 32 (12), 1591-1599.

Field Calibrations

Independent salinity and fluoresence samples, obtained from the sample bottle and spread throughout the cruise, were used to calibrate the CTD conductivity and fluoresence data. Outlying points were discarded, and between 25 and 84 data points were used to derive the calibrations. The sample analyses yielded a straight line conductivity calibration of the form y = mx + c, where m = 0.999606 and c = 0.009397 (conductivity) and where m = 0.005222 and c = -0.783526 (fluoresence).

The calibrated and uncalibrated data were submitted to BODC, who applied the appropriate corrections.

Project Information

No Project Information held for the Series

Data Activity or Cruise Information

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Faroe-Cape Wrath Transect

The Faroe-Cape Wrath transect was started for the THOR (Thermohaline Overturning - at Risk?) project (2007-2013) and has now continued under NACLIM (North Atlantic Climate Variability) project (2012-2017), both projects ran under European Union (EU) Seventh Framework Programme (FP7).

Marine Scotland first sampled the transect in May 2009. Marine Scotland hope to sample this line twice a year (April-May and September-October) and if possible in December.

The stations along this line will be mainly used for CTD deployments although salinity samples will be taken along the line for calibration purposes. Some nutrient samples have been taken by Marine Scotland but it is not anticipated that nutrient sampling will become a regular occurrence.

The Faroese are also sampling this line.

Map of standard stations

Line Stations

Listed below are details of the standard hydrographic stations that form the Faroe-Cape Wrath line.

Faroe - Cape Wrath (extended line)

This line is not shown on the map but may be sampled occasionally.

CTD sampling history

Cruise FRV Scotia 0512S, between 07 May 2012 - 22 May 2012, sampled stations FWZ-01 to FWZ-19 inclusively.

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: Faroe-Cape Wrath Transect

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.