Metadata Report for BODC Series Reference Number 2295670

• 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 Cruise JC238 Sea-Bird SBE 37 MicroCAT data from Ellett Array Icelandic Basin Moorings IB3, IB4 and IB5

During BODC processing, the BODC quality control improbable value flag (M) was applied to data values in the PSALTC01 channel that are beyond the parameter limit (41.5 psu). Additionally, the start of data files have been trimmed to remove null data cycles where this was present across all channels during mooring deployment.

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 SBE 37-SMP MicroCAT

The SBE 37-SMP MicroCAT is a high accuracy conductivity and temperature recorder (pressure optional) with Serial interface, internal battery, non-volatile FLASH Memory and integral Pump. The Integral Pump runs for 1 second each time the MicroCAT samples, improving the conductivity response and giving improved anti-foul protection.

Designed for moorings and other long-duration, fixed-site deployments, MicroCATs have non-corroding titanium housings rated for operation to 7000 meters or pressure sensor full scale-range. Communication with the MicroCAT is over an internal, 3-wire, RS-232C link. The MicroCAT's aged and pressure-protected thermistor has a long history of exceptional accuracy and stability (typical drift is less than 0.002°C per year). Electrical isolation of the conductivity electronics eliminates any possibility of ground-loop noise.

Specifications

Further information can be found via the following link: Sea-Bird SBE 37-SMP MicroCAT Datasheet

BODC Processing of Cruise JC238 Sea-Bird SBE 37 MicroCAT data from Ellett Array Icelandic Basin Moorings IB3, IB4 and IB5

The Sea-Bird SBE 37 MicroCAT data were supplied to BODC as ASCII files and converted to BODC internal format (QXF). During transfer the originator's variables were mapped to unique BODC parameter codes. The following table shows the parameter mapping:

Following transfer the data were screened using BODC in-house visualisation software. Suspect data values were assigned the appropriate BODC data quality flag. Missing data values, where present, were changed to the missing data value and assigned a BODC data quality flag.

Originator's Processing of Cruise JC238 Sea-Bird SBE 37 MicroCAT data from Ellett Array Icelandic Basin Moorings IB3, IB4 and IB5

Sampling Strategy

During RRS James Cook cruise JC238, 12 Sea-Bird SBE 37 SMP-CTP MicroCATs were deployed at the IB3 site, 12 at the IB4 site and 7 at the IB5 site. Additionally, 4 Sea-Bird SBE 37 SMP-CTP-ODO MicroCATs were deployed at the IB4 site. The MicroCATs were fitted with new batteries (SAFT 3.6V Lithium AA cells) and their clocks were synchronised with GPS time. All the SMP-CTP MicroCATs were set to sample every 1800 seconds, while the SMP-CTP-ODO MicroCATs sampled either every 3600 or 4500 seconds. All MicroCATs were set to record pressure, temperature and conductivity, while the SMP-CTP-ODO MicroCATs also recorded oxygen. All instruments were recovered during RRS Discovery cruise DY181.

Data Acquisition, Calibration and Initial Processing

All MicroCATs were cal-dipped prior to deployment and post recovery, and the data were corrected for sensor drift and offsets using all these measurements.

After recovery, the instruments deployed in the top 100 to 200m and those just above the bottom showed quite significant biofouling, however none near the cell intake and exhaust, which were fitted with antifoulant devices. SMP-CTP MicroCAT S/N 11139 (IB3 1500m) was recovered with an obstruction in the CT cell exhaust, thought to be a degraded antifoulant. However the data from this MicroCAT are unaffected.

Most of the SMP-CTP MicroCATs reported a clock drift of less than 1 minute from UTC time, with some of the older instruments (serial numbers <5000) showing a larger offset of up to 3.75 minutes. The SMP-CTP-ODO MicroCATs reported a clock drift of less than 1 minute from UTC time, except for S/N 12908 (IB4 350m) which had drifted by -10 minutes 45 seconds.

The raw data were converted to cnv in SBEDataProcessing (DatCnv module) for SBE37's v>=3.0, and in SeaTerm using the 'Convert' tool for SBE37's v<=3.0. All instruments recorded data for the full deployment period and no major issues were observed in the data. The processed data were supplied to BODC for banking. Dissolved oxygen data was not included and will be ingested separately by BODC.

Deployment Cruise Information

Further information can be found in the deployment cruise summary report for RRS James Cook JC238

Recovery Cruise Information

Further information can be found in the recovery cruise summary report for RRS Discovery DY181

Project Information

UK - Overturning in the Subpolar North Atlantic Programme (UK-OSNAP) Programme

UK-OSNAP is part of an international collaboration to establish a transoceanic observing system in the subpolar North Atlantic. The aim is to quantify and understand the Subpolar Gyre's response to local and remote forcing of mass, heat and freshwater fluxes, within the conceptual framework of the Atlantic Meridional Overturning Circulation (AMOC).

UK-OSNAP is developing a new observing system to provide a continuous record of full-depth, trans-basin mass, heat, and freshwater fluxes. Combining these sustained measurements with innovative modelling techniques will enable the project to characterise the circulation and fluxes of the North Atlantic Subpolar Gyre.

UK-OSNAP is funded by the Natural Environment Research Council (NERC). The project is led by the National Oceanography Centre (NOC) with partners in the University of Liverpool, the University of Oxford and the Scottish Association for Marine Science (SAMS). It is a part of international OSNAP that is led by USA and includes 10 further partner groups in Canada, France, Germany, the Netherlands and China. The project involves fieldwork at sea and model studies.

The OSNAP observing system consists of two legs: one extending from southern Labrador to the southwestern tip of Greenland across the mouth of the Labrador Sea (OSNAP West), and the second from the southeastern tip of Greenland to Scotland (OSNAP East). The observing system also includes subsurface floats (OSNAP Floats) in order to trace the pathways of overflow waters in the basin and to assess the connectivity of currents crossing the OSNAP line.

NERC have added an extension to UK-OSNAP, until October 2024. This will result in the UK-OSNAP-Decade: 10 years of observing and understanding the overturning circulation in the subpolar North Atlantic (2014-2024).

Data Activity or Cruise Information

Data Activity

Ellett Array Moored Instruments IB4 2022-2024

This rig was deployed as part of the Iceland Basin Array.

The rig was held down by a 1900 kilogram anchor on the seabed at 2919 metres depth. It was kept erect by 44" syntactic float at 75 metres depth and 2 glass spheres at 45 metres depth.

The instruments deployed on the rig were as follows:

Issues with mooring and sensors

The oxygen sensor failed at the start of the cal-dip on MicroCAT SMP-CTP-ODO S/N 12908 (349 m). Temperature and conductivity data are unaffected.
The Nortek Aquadopp S/N 11021 (1496 m) was found to be flooded (water ingress at bulkhead connector) and the data could not be retrieved.
The downward looking RDI WorkHorse 300kHz ADCP S/N 24589 was recovered flooded with its pressure sensor missing. No data were recovered.

Related Data Activity activities are detailed in Appendix 1

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Extended Ellett Line: Fixed Station IB4

Station IB4 is one of the fixed CTD stations, which together form The Extended Ellett Line. The line lies between Iceland and the Sound of Mull (Scotland) crossing the Iceland Basin and Rockall Trough via the outcrop of Rockall. As part of this initiative, CTD dips, together with associated discrete sampling of the water column, have typically been carried out annually at this station since September 1996.

From 2018 this mooring contributed to the UK-OSNAP project. It was referred to as the OSNAP Iceland Basin Array.

Related Fixed Station activities are detailed in Appendix 2

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: IB4_03_2022

Related series for this Data Activity 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.

Appendix 2: Extended Ellett Line Station IB4

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.