Metadata Report for BODC Series Reference Number 2202680

• 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

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"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.

JC237 CTD (Conductivity-Temperature-Depth) Instrumentation

The Sea-Bird Scientific SBE911plus CTD was mounted on a rosette with a SBE32 carousel water sampler and 24 10 L OTE bottles. The CTD was fitted with the following scientific sensors:

Additional Information

A single SBE 43 dissolved oxygen sensor was used on the primary channel. The primary temperature, conductivity and dissolved oxygen sensors were mounted to the 9plus within the CTD frame. The secondary temperature and conductivity sensors were mounted on the vane.

Sea-Bird Electronics SBE 911 and SBE 917 series CTD profilers

The SBE 911 and SBE 917 series of conductivity-temperature-depth (CTD) units are used to collect hydrographic profiles, including temperature, conductivity and pressure as standard. Each profiler consists of an underwater unit and deck unit or SEARAM. Auxiliary sensors, such as fluorometers, dissolved oxygen sensors and transmissometers, and carousel water samplers are commonly added to the underwater unit.

Underwater unit

The CTD underwater unit (SBE 9 or SBE 9 plus) comprises a protective cage (usually with a carousel water sampler), including a main pressure housing containing power supplies, acquisition electronics, telemetry circuitry, and a suite of modular sensors. The original SBE 9 incorporated Sea-Bird's standard modular SBE 3 temperature sensor and SBE 4 conductivity sensor, and a Paroscientific Digiquartz pressure sensor. The conductivity cell was connected to a pump-fed plastic tubing circuit that could include auxiliary sensors. Each SBE 9 unit was custom built to individual specification. The SBE 9 was replaced in 1997 by an off-the-shelf version, termed the SBE 9 plus, that incorporated the SBE 3 plus (or SBE 3P) temperature sensor, SBE 4C conductivity sensor and a Paroscientific Digiquartz pressure sensor. Sensors could be connected to a pump-fed plastic tubing circuit or stand-alone.

Temperature, conductivity and pressure sensors

The conductivity, temperature, and pressure sensors supplied with Sea-Bird CTD systems have outputs in the form of variable frequencies, which are measured using high-speed parallel counters. The resulting count totals are converted to numeric representations of the original frequencies, which bear a direct relationship to temperature, conductivity or pressure. Sampling frequencies for these sensors are typically set at 24 Hz.

The temperature sensing element is a glass-coated thermistor bead, pressure-protected inside a stainless steel tube, while the conductivity sensing element is a cylindrical, flow-through, borosilicate glass cell with three internal platinum electrodes. Thermistor resistance or conductivity cell resistance, respectively, is the controlling element in an optimized Wien Bridge oscillator circuit, which produces a frequency output that can be converted to a temperature or conductivity reading. These sensors are available with depth ratings of 6800 m (aluminium housing) or 10500 m (titanium housing). The Paroscientific Digiquartz pressure sensor comprises a quartz crystal resonator that responds to pressure-induced stress, and temperature is measured for thermal compensation of the calculated pressure.

Additional sensors

Optional sensors for dissolved oxygen, pH, light transmission, fluorescence and others do not require the very high levels of resolution needed in the primary CTD channels, nor do these sensors generally offer variable frequency outputs. Accordingly, signals from the auxiliary sensors are acquired using a conventional voltage-input multiplexed A/D converter (optional). Some Sea-Bird CTDs use a strain gauge pressure sensor (Senso-Metrics) in which case their pressure output data is in the same form as that from the auxiliary sensors as described above.

Deck unit or SEARAM

Each underwater unit is connected to a power supply and data logging system: the SBE 11 (or SBE 11 plus) deck unit allows real-time interfacing between the deck and the underwater unit via a conductive wire, while the submersible SBE 17 (or SBE 17 plus) SEARAM plugs directly into the underwater unit and data are downloaded on recovery of the CTD. The combination of SBE 9 and SBE 17 or SBE 11 are termed SBE 917 or SBE 911, respectively, while the combinations of SBE 9 plus and SBE 17 plus or SBE 11 plus are termed SBE 917 plus or SBE 911 plus.

Specifications

Specifications for the SBE 9 plus underwater unit are listed below:

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

Sea-Bird SBE 9plus CTD

High precision and accuracy CTD comprising an SBE 9plus underwater unit (SBE 3plus temperature, SBE 4C conductivity, and Paroscientific Digiquartz pressure sensors, and an SBE 5T submersible pump). Can be used for either real-time data acquisition or for autonomous operations at a sampling speed of up to 24 Hz. The instrument package also includes a TC duct, to reduce salinity spiking caused by ship heave for improved resolution of water column features, and to ensure that temperature and conductivity measurements are made on the same parcel of water. Supplied with both an aluminium and titanium main housing, allowing for use up to 6800 and 10,500 metre depths respectively. Also capable of measuring from eight auxiliary sensors.

For more information, please see this document: https://www.bodc.ac.uk/data/documents/nodb/pdf/SeaBird_SBE_9plus_Manual.pdf

Chelsea Technologies Group Aquatracka MKIII fluorometer

The Chelsea Technologies Group Aquatracka MKIII is a logarithmic response fluorometer. Filters are available to enable the instrument to measure chlorophyll, rhodamine, fluorescein and turbidity.

It uses a pulsed (5.5 Hz) xenon light source discharging along two signal paths to eliminate variations in the flashlamp intensity. The reference path measures the intensity of the light source whilst the signal path measures the intensity of the light emitted from the specimen under test. The reference signal and the emitted light signals are then applied to a ratiometric circuit. In this circuit, the ratio of returned signal to reference signal is computed and scaled logarithmically to achieve a wide dynamic range. The logarithmic conversion accuracy is maintained at better than one percent of the reading over the full output range of the instrument.

Two variants of the instrument are available, both manufactured in titanium, capable of operating in depths from shallow water down to 2000 m and 6000 m respectively. The optical characteristics of the instrument in its different detection modes are visible below:

* The wavelengths for the turbidity filters are customer selectable but must be in the range 400 to 700 nm. The same wavelength is used in the excitation path and the emission path.

The instrument measures chlorophyll a, rhodamine and fluorescein with a concentration range of 0.01 µg l^-1 to 100 µg l^-1. The concentration range for turbidity is 0.01 to 100 FTU (other wavelengths are available on request).

The instrument accuracy is ± 0.02 µg l^-1 (or ± 3% of the reading, whichever is greater) for chlorophyll a, rhodamine and fluorescein. The accuracy for turbidity, over a 0 - 10 FTU range, is ± 0.02 FTU (or ± 3% of the reading, whichever is greater).

Further details are available from the Aquatracka MKIII specification sheet.

Biospherical Instruments QCP-2350-HP [underwater] PAR sensor

A cosine-corrected PAR quantum irradiance profiling sensor. For use in high-pressure underwater applications with 24 bit ADC systems. Measures light available for photosynthesis on a flat surface. Operation is by a single channel compressed analog output voltage that is proportional to the log of incident PAR (400-700 nm) irradiance. A variant of the QCP-2350 model, it uses a pressure-tolerant BH-4-MP connector. The sensor is designed for operation in waters to depths of up to 10,000 m.

For more information, please see this document: https://www.bodc.ac.uk/data/documents/nodb/pdf/Biospherical_QCP2300_QCP2350_Apr2014.pdf

WETLabs Single-angle Backscattering Meter ECO BB

An optical scattering sensor that measures scattering at 117°. This angle was determined as a minimum convergence point for variations in the volume scattering function induced by suspended materials and water. The measured signal is less determined by the type and size of the materials in the water and is more directly correlated to their concentration.

Several versions are available, with minor differences in their specifications:

• ECO BB(RT)provides analog or RS-232 serial output with 4000 count range
• ECO BB(RT)D adds the possibility of being deployed in depths up to 6000 m while keeping the capabilities of ECO BB(RT)
• ECO BB provides the capabilities of ECO BB(RT) with periodic sampling
• ECO BBB is similar to ECO BB but with internal batteries for autonomous operation
• ECO BBS is similar to ECO BB but with an integrated anti-fouling bio-wiper
• ECO BBSB has the capabilities of ECO BBS but with internal batteries for autonomous operation

Specifications

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

Valeport VA500 altimeter

A titanium-housed acoustic altimeter used for underwater positioning to determine distance to or height above the seabed. Can be mounted used on ROVs, AUVs and other such platforms for various underwater construction and hydrographic applications. The VA500 features a 500kHz broadband transducer offering a range of 0.1m to 100m, a resolution of 1mm and a beam angle +/- 3 degrees. It features RS232 and RS485 digital output as standard, and is supplied with free DataLog X2 software for instrument setup and data display. An optional Valeport miniIPS pressure sensor can be added. The pressure sensor is a temperature compensated piezo-resistive sensor with various ranges available, an accuracy +/- 0.01 percent FS, and a resolution of 0.001 percent FS. The VA500 is depth-rated to 6000m.

For more information, please see this document: https://www.bodc.ac.uk/data/documents/nodb/pdf/Valeport-VA500-Altimeter-Datasheet.pdf

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.

Processing by BODC of JC237 CTD (Conductivity-Temperature-Depth) Data

The JC237 cruise departed Southampton on 6th August 2022, and returned on 4th September 2022. 21 CTD casts were undertaken with an NMF (National Marine Facility) 24-way Stainless Steel CTD frame with 24 off 10l OTE water samplers. 20 CTD casts were undertaken at the Whittard Canyon and 1 cast (Cast 019) undertaken at the PAP site (Porcupine Abyssal Plain) with an. The CTD data were supplied to BODC as 21 MATLAB files.

Basic checks of the data and metadata were carried out and the data were subsequently transferred to BODC internal format (a netCDF subset). During transfer the originator's variables were mapped to unique BODC parameter codes, and some variables were derived by BODC from originator variables. The following table shows the parameter mapping:

Following transfer the data were screened using BODC in-house visualisation software. Any suspect data were flagged using the BODC quality control flags.

Processing by originator of JC237 CTD (Conductivity-Temperature-Depth) Data

Sampling Strategy

In total 21 CTD (Conductivity-Temperature-Depth) cast deployments were used to obtain profiles of the water column from a range of sensors comprising of temperature, conductivity, pressure, oxygen, fluorescence, turbidity, transmittance, and attenuance. 21 CTD casts were undertaken with an NMF 24-way Stainless Steel CTD frame with 24 off 10l OTE water samplers. A single SBE 43 dissolved oxygen sensor was used on the primary channel. The primary temperature, conductivity and dissolved oxygen sensors were mounted to the 9plus [Seabird SBE 9plus, serial number 09-0803] within the CTD frame. The secondary temperature and conductivity sensors were mounted on the vane. The deepest cast was CTD001 at station 02 which descended to 4031m. The shallowest cast was CTD002 at station 08 which descended to 407m.

To reduce wasted time spent approaching the bottom and the surface, the rosette was only taken to 50 m from the seabed and 50 m from the surface in each cast cycle.

Initial Data Processing

There were no major technical issues with the CTD suite during the cruise and no scientific instruments required changing for spares.

Sea-Bird CTD data processing of the raw data was completed using Sea-Bird Data Processing software. Processing the raw data followed the BODC recommended guidelines for processing of SBE-911 CTD data (BODC Document version 1.0 October 2010). Outlined below are the processing routines used for all casts:

• Data Conversion
• Bottle Summary
• SeaPlot of pressure time-series to confirm no pressure spikes - WildEdit did not need to be run
• Filter 0.15 s on pressure only
• AlignCTD 6 s on oxygen channel only
• CellTM
• Derive - Depth Salt Water, Salinities, Oxygen Concentration - also separately SV
• BinAverage in 2 Hz for BODC
• Strip - to remove Depth Salt Water, Salinities and Oxygen Concentration
• ASCII Out for 1 Hz (stripped), 2 Hz (stripped) and 25 m SVP

Scan count, elapsed time (seconds), NMEA latitude and longitude, and all instrument channels in engineering units and raw voltages were selected for data conversion. The primary and secondary channels were output in µmol/kg and SBE raw V. The pressure hysteresis correction for Oxygen was selected in the conversion.

Calibrations and Further Data Processing

Please see the JC237 cruise report for details of the calibration coefficients applied to the data for all casts.

During the JC237 cruise to the Whittard Canyon, the CTD data from JC125 were reassessed and compared with the new JC237 CTD data. It was noticed that the calibration coefficients originally applied to the chlorophyll fluorometer and turbidity sensors were incorrect in JC125, and these data were separately resubmitted to BODC. Please see the JC237 cruise report for more information.

Chelsea Technologies Group Aquatracka III fluorometer (s/n: 08-2615-126) Calibration date: 06-Aug-2014 V1: 2.2537 WETLabs ECO-BB turbidity sensor (s/n: 169) Calibration date: 09-Aug-2013 Scale factor: 4.011 x10^-3 m/sr/V Dark voltage: 0.0924 V

During processing, the CTD data from all casts were averaged (down-casts and up-casts combined, median value) into 2 m and 8 m bins, the latter to match the resolution of the LADCP profiles. Note that the CTD dataset supplied to BODC is 2 m binned. The data were output into MATLAB files.

Project Information

Marine LTSS: CLASS (Climate Linked Atlantic Sector Science)

Introduction

CLASS is a five year (2018 to 2023) programme, funded by the Natural Environment Research Council (NERC) and extended until March 2024.

Scientific Rationale

The ocean plays a vital role in sustaining life on planet Earth, providing us with both living resources and climate regulation. The trajectory of anthropogenically driven climate change will be substantially controlled by the ocean due to its absorption of excess heat and carbon from the atmosphere, with consequent impacts on ocean resources that remain poorly understood. In an era of rapid planetary change, expanding global population and intense resource exploitation, it is vital that there are internationally coordinated ocean observing and prediction systems so policy makers can make sound evidence-based decisions about how to manage our interaction with the ocean. CLASS will underpin the UK contribution to these systems, documenting and understanding change in the marine environment, evaluating the impact of climate change and effectiveness of conservation measures and predicting the future evolution of marine environments. Over the five-year period CLASS will enhance the cost-effectiveness of observing systems by migrating them towards cutting edge autonomous technologies and developing new sensors. Finally, CLASS will create effective engagement activities ensuring academic partners have transparent access to NERC marine science capability through graduate training partnerships and access to shipborne, lab based and autonomous facilities, and modelling capabilities.

Data Activity or Cruise Information

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Porcupine Abyssal Plain (PAP) Observatory

The Porcupine Abyssal Plain (PAP) observatory is a site at which moorings were deployed in the Northeastern Atlantic, as part of the ANIMATE (Atlantic Network of Interdisciplinary Moorings and Time-series for Europe), MERSEA (Marine Environment and Security for the European Area), EuroSITES, Oceans2025, Fix03 and CLASS projects. The PAP site is centred at latitude 49° N and longitude 16.5° W. Moorings have occupied this region since 2002 and are typically deployed for 12 months.

Please note: Near Real Time data is only stored at BODC where delayed mode data were not recovered. All near real time data can be found at the OceanSites GDA and through IFREMER.

Data summary

Status Indicators

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: Porcupine Abyssal Plain (PAP)

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.