Metadata Report for BODC Series Reference Number 1178582

• 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 Quality Document

Temperature, salinity, sigma-theta and litre to kilogram conversion factor:

There were no data quality issues detected during screening. The profiles are consistent with what might be expected for the location and time of year.

Fluorometer voltage:

The profile trends match well with the transmissometer trends (high fluorometer voltages corresponding to low transmission). Since this is a voltage there are no comments on the absolute values. There is natural variability in the profile but nothing considered suspect that required flagging.

Transmission:

The profile trends match well with the fluorometer voltage trends (high fluorometer voltages corresponding to low transmission). Values do not exceed 100%. There is natural variability in the profile but nothing considered suspect that required flagging.

Downwelling PAR irradiance:

The trend is consistent with what would be expected for each profile. Noise in the surface bins can be due to changing cloud cover. There is natural variability in the profiles but nothing considered suspect that required flagging.

Dissolved oxygen concentration and saturation:

There were no data quality issues detected during screening. The profiles are consistent with what might be expected for the location and time of year.

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

Sea-Bird Dissolved Oxygen Sensor SBE 43 and SBE 43F

The SBE 43 is a dissolved oxygen sensor designed for marine applications. It incorporates a high-performance Clark polarographic membrane with a pump that continuously plumbs water through it, preventing algal growth and the development of anoxic conditions when the sensor is taking measurements.

Two configurations are available: SBE 43 produces a voltage output and can be incorporated with any Sea-Bird CTD that accepts input from a 0-5 volt auxiliary sensor, while the SBE 43F produces a frequency output and can be integrated with an SBE 52-MP (Moored Profiler CTD) or used for OEM applications. The specifications below are common to both.

Specifications

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

Instrument description

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.

Chelsea Instruments MINI^tracka Fluorometer

The MINI^tracka Fluorometer is an in-situ optical sensor that uses a single high intensity LED light source and, according to the manufacturer, is designed to enhance rejection of ambient daylight. The fluorometer provides a linear response between chlorophyll concentration and fluorometer voltage.

Sensor specifications, current at August 2006, are given in the table below. More information can be found at the manufacturer's specification sheet.

Sensor Specifications

Chelsea Technologies Photosynthetically Active Radiation (PAR) Irradiance Sensor

This sensor was originally designed to assist the study of marine photosynthesis. With the use of logarithmic amplication, the sensor covers a range of 6 orders of magnitude, which avoids setting up the sensor range for the expected signal level for different ambient conditions.

The sensor consists of a hollow PTFE 2-pi collector supported by a clear acetal dome diverting light to a filter and photodiode from which a cosine response is obtained. The sensor can be used in moorings, profiling or deployed in towed vehicles and can measure both upwelling and downwelling light.

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.

Data Processing

Originator's Sampling Strategy

These data were collected using a CTD rig deployed from PML research vessels.

Originator's Processing

The raw CTD data were processed using the Sea-Bird software. The data were provided in tab delimited format.

BODC post-processing and screening

Reformatting

The data were converted from tab delimited format into BODC internal format using BODC transfer function 401. During transfer the depth variable was converted to pressure using the routine 'sw_pres', a part of the Seawater toolbox, this used the method of Fofonoff and Millard Jr. (1983) using inputs of depth and latitude. The density parameter was not transferred by BODC as this is generated to a standard algorithm during BODC transfer.

The measured variables were mapped to BODC parameter codes shown in the table below:

Screening

Reformatted CTD data were transferred onto a graphics work station for visualisation using the in-house editor EDSERPLO. No data values were edited or deleted. Flagging was achieved by modification of the associated BODC quality control flag for suspect or null values.

Banking

The profiles were banked to the National Oceanographic Database (NODB) following BODC procedures.

References

Benson, B.B. and Krause, D., 1984. The concentration and isotopic fractionation of oxygen dissolved in freshwater and seawater in equilibrium with the atmosphere. Limnol. Oceanogr., 29(3), 620-632.

Fofonoff, N.P. and Millard, R.C., 1983. Algorithms for computations of fundamental properties of seawater. UNESCO Technical Papers in Marine Science No. 44, 53pp.

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

Western Channel Observatory station L4

The Western Channel Observatory (WCO) is situated in the Western English Channel and comprises of long-term sustained observations at a number of stations.

Station L4 is located south-west of Plymouth at 50°15.00N, 4°13.02W.

More information can be found on the Western Channel Observatory website.

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: Western Channel Observatory L4

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.