Metadata Report for BODC Series Reference Number 1912592

• 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 report for CTD deployments by Marine Scotland Science during 2017

Data have been through thorough quality control checks conducted by Marine Scotland Science (MSS) and any quality control flags applied by MSS have been applied to the data during BODC processing. Additionally, improbable flags ('M') were applied to any derived parameters where MSS flagged a value as bad data in a channel used in the derivation. An improbable flag ('M') was also added to cycles in derived PSALST01 where CNDCST01 was interpolated by the MSS as the interpolation looked to be linear and resulted in large spikes in the PSALST01 channel.

In addition to MSS quality checks, data were also screened by BODC using in house visualisation software during BODC processing. The following cycles have been flagged 'M' during BODC screening due to the value being an obvious outlier when compared to the rest of the CTD cast:

CCOMD002

• series 1916520: cycles 1 and 2
• series 1916556: cycle 1
• series 1916581: cycle 1
• series 1916600: cycle 2
• series 1916612: cycle 1
• series 1916661: cycle 1

DOXYZZ01 and OXYSSU01

• series 1911712: cycle 1 has been flagged as the values are very low value when compared to rest of profile.

TURBXXXX

• series 1916520: cycle 2
• series 1916556: cycle 1

TEMPPR01 and POTMCV01

There are a few instances in TEMPPR01 and POTMCV01 where the first cycle of the profiles is an outlier when compared to the rest of the cast. However, as these values have been flagged good data by MSS they have not been flagged during BODC screening.

CPHLPR01 and CPHLPS01

There are spikes in the CPHLPR01 and CPHLPS01 parameters at the surface of a number of casts from cruise 1717S. As these have not been flagged by the originator and are from a similar area and time the values have not been flagged during BODC screening.

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

Instrumentation used for CTD deployments by Marine Scotland Science during 2017

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.

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.

BODC Processing of Marine Scotland Science CTD deployments during 2017

Data Processing

Data were submitted to BODC as 12 ASCII files by email and following BODC procedures the data were archived. The data from all cruises in 2017 were accompanied by a file of quality control flags. During BODC proccessing these flags were applied to the data. The header of each file contained the type of CTD used for each cruise, the sensors on the CTD and their serial numbers, an explanation of the format of the file and details of any calibrations.

The concatenated files were sub-divided into individual files for each cast using in house BODC Matlab software. The divided files were then transferred to BODC internal format using standard BODC processing procedures. The originator's variables were mapped to BODC parameter codes as follows:

Channels that were not transferred are available on request.

Screening

Post transfer analysis and crosschecks were applied according to BODC procedures. This involved the screening of data using BODC's in house visualisation software where any suspect data were flagged but not removed. During screening it was also checked that the originator's flags had been applied to the data correctly.

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.

Originator Processing of Marine Scotland Science CTD deployments during 2017

Sampling Strategy

During 2017 a number of Marine Scotland cruises occurred on the FRV Scotia and FRV Alba Na Mara were objectives covered trawl sampling, fish sampling, acoustic surveys and hydrographic sampling. As part of the hydrographic sampling numerous CTD casts were completed on each cruise. The time channel of these casts was recorded in GMT.

Data Processing

The CTD data were processed by Marine Scotland using the Sea-Bird SeaSoft routines as recommended in the SeaSoft manual for model type Sea-Bird SBE19plus V2 SEACAT.

Pressure data were binned to 1 dbar using SeaSoft and the primary temperature and conductivity channels were adjusted to produce 'edit' channels. Marine Scotland regards the 'edit' channels as the definitive version of the data.

The adjustments consisted of a de-spiking process using Marine Scotland in-house visualisation software and, as necessary, application of a low pass filter as described in Sy (1985).

Field Calibrations

For a number of the cruises Marine Scotland used water samples collected during the CTD casts to generate a calibration equations for the conductivity and fluorescence channels. However, these calibrations were not applied to the data by the originator. The available calibrations are as follows:

Conductivity

Fluorescence

Oxygen

Reference

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

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

No Fixed Station Information held for the Series

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: