Metadata Report for BODC Series Reference Number 1218149

• 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

Gunnet Ledge Quality Report

Screening and QC

The data have had QC applied by SEPA with suspect data being removed. Data then went through BODC QC procedures.

During BODC screening noisy periods were observed in several parameters but these periods were generally left unflagged. Spikes in all channels were looked at in closer detail and M flags were applied if necessary. Null values were assigned an N flag.

Several series (1217890, 1217969, 1217970, 1217994 and 1218008) exhibit noisy CPHLZZXX and TURBXXXX data. These data have not been flagged as they were considered real events, however they should be used with caution. TURBXXXX and CPHLZZXX also exhibit occasional high values in some series which may be related to particles adhering to the sensor. For series 1217945, 1218740 and 1218764, CPHLZZXX appears to have quality issues and suspect flags were applied to any values of 500 mg m^-3, all other points were left unflagged. Users are advised to use caution when dealing with these data. The same caution is advised for DOXYZZ01 and OXYZZ01 data for series 1218703, as the channels are extremely noisy.

Duplicate cycles were found in series 1218531 and 1218579 during BODC processing. All parameters in the duplicate cycle in series 1218531 were null and so the duplicate cycle was deleted. In series 1218579, all parameters were null in the duplicate cycles apart from TEMPPR01. The duplicate cycles were removed and TEMPPR01 was then interpoltaed and flagged T during BODC QC for these cycles.

Ship service visits were taken at a single point in time, where stated in the originator's data.

During BODC processing, any null periods in the data were removed where a parameter was null for the duration of a cruise-to-cruise event. Null periods were removed as follows:

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

YSI 6-Series multiparameter water quality sondes

Basic information

Comprehensive multi-parameter, water quality monitoring sondes. Designed for long-term monitoring, profiling and spot sampling. The 6-series may be split into several categories: V2 Sondes, 600 Sondes, Drinking Water Sondes and System. Each category has a slightly different design purpose with V2 Sondes ideal for long-term monitoring with a greater number of parameters, whereas 600 sondes are ideal for specific applications with fewer parameters available.

Model features/parameters

^*Freshwater only^**Calculated parameters

Sensor Specifications

For further information, please see the manufacturer's manual and data sheet.

SEPA Mooring Instrumentation

The SEPA long-term monitoring project has obtained hydrographic data across various moorings through the deployment of a YSI 6600 multi-parameter-sonde attached to a fixed mooring buoy at the surface of the water column.

These mooring sites include: Dunoon, Gunnet Ledge, Inner Clyde Estuary, Campbelltown, Loch Striven, Ythan, Loch Sunart, South Alloa, and Moray Firth.

The South Alloa site had two Hydrolab MS5 probes up until the 3rd of March 2011, at which point a YSI 6600 probe was used.

The Inner Clyde Estuary site also has a probe attached approximately 1 m from the sea floor in addition to the probe at the surface.

The Moray Firth site was monitored solely between July and December 2018.

The depth of the sensors at the time of measurement at each site is available upon request for the 2016 and 2017 data.

The turbidity sensors are deemed, by the manufacturer, to be used as guidance in events such as observing storm events or spotting discharges. SEPA rely on a suspended solids laboratory procedure for their turbidity reported data. The same situation occurs for chlorophyll, SEPA have a lab method they use to report it as high turbidity can interfere with the readings. This is not generally an issue in low turbidity areas.

BODC processing of SEPA's long-term monitoring buoys

Data Acquisition and Transfer

The data were sent by SEPA as yearly .csv files and following BODC's procedures the files were checked for consistency and subsequently archived.

The data were reformatted to QXF format using BODC's established procedures. During the transfer process each yearly file was split into cruise-to-cruise series events. The table below shows how the originator's parameters were mapped to BODC parameters and their units:

Data Quality and Screening

Not all parameters occur in all series, particularly pH, turbidity and chlorophyll.

Oxygen saturation is not derived by BODC for consistency across all years and due to missing channels as mentioned in the originator's processing document.

The standard unit conversion factor of * 31.252 was applied to oxygen concentration during transfer to obtain the BODC units of µmol/l. (Bittig et al., 2018)

Post transfer analysis and crosschecks were applied according to BODC procedures. This involved the screening of data to check flags were appropriately applied whilst also applying further quality control flags where appropriate. Originator flags for "No sensor; Quality Control failure; Quality Control Spike Removed; Quality Control Spike removed, wiper incorrectly parking over sensor; Power Failure, Sensor failure" were all flagged as 'Null' as no data were available when these were applied.

References

Bittig, H., Körtzinger, A., Johnson, K., Claustre, H., Emerson, S., Fennel, K., ... & Xing, X. 2018. SCOR WG 142: Quality Control Procedures for Oxygen and Other Biogeochemical Sensors on Floats and Gliders. Recommendations on the conversion between oxygen quantities for Bio-Argo floats and other autonomous sensor platforms.

SEPA originator's processing document for Gunnet Ledge long-term monitoring buoy

Data Acquisition and Analysis

Data were obtained from a YSI probe attached to a mooring deployed in the inner Firth of Forth, off Gunnet Ledge. The mooring was serviced and deployed by the Scottish Environment Protection Agency (SEPA) for the purpose of long-term monitoring. The raw data were downloaded directly from the instruments sometimes remotely. This initially caused problems as sometimes data strings would be overwritten if the function was set up incorrectly leading to one parameter being downloaded at the expense of another. Data were sent in GMT format.

Quality and Screening

Once downloaded the data went through SEPA data quality checks with suspect data removed and relevant flags attached to inform future users of the reason for any missing data. This information is available upon request.

Submission

The data were then submitted to BODC through ftp as yearly .csv files.

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

Gunnet Ledge SEPA moooring

The buoy is located in the Inner Firth of Forth, at Gunnet Ledge, and provides measurements of dissolved oxygen, salinity, temperature, pH, chlorophyll and turbidity. Its maintenance is done on a monthly basis and is done in such a way as to prevent loss of information, this usually involves a change in the probe that is installed in the buoy, thus making readings continuous through time. The monitoring at this location is used in conjunction with regular collection of physical samples to assess the status of the coastal waters of the Inner Firth of Forth, as part of SEPA's obligations to the Water Framework Directive and OSPAR.

The sampling interval was initially set to collect a measurement every 30 minutes but this interval has been changed to collect samples every 15 minutes.

The water depth where the buoy is moored was retrieved from a nautical chart. The depth should be used with caution.

More information may be found at the SEPA monitoring buoy network page for Gunnet Ledge.

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: SEPA_GLedge

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.