Metadata Report for BODC Series Reference Number 1911343

• 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 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.

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: