Metadata Report for BODC Series Reference Number 1198614

• 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 supplied by Natural Environment Research Council (NERC)

You must always use the following attribution statement to acknowledge the source of the information: "Contains data supplied by Natural Environment Research Council."

Narrative Documents

Vemco Minilog8 TR temperature logger

The VEMCO Minilog8-TR is a miniature data logger that records temperature at a user programmed time interval. It is housed in a waterproof cylinder and the temperature sensor is mounted on a protruding stainless steel probe.

Specifications

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

D376 moored instrumentation: Originator's data processing

Sampling Strategy

The RRS Discovery D376 was the first of two cruises funded by the NERC Consortium grant for the Fluxes Across the Sloping Topography of the North East Atlantic (FASTNEt) project. D376 was a 19 day cruise sailing on 11 June 2012 from Swansea dry dock to the Celtic Sea shelf edge where a total of four short term in-line moorings were deployed before returning to Southampton on 2 July 2012.

Data Processing

The Originator has supplied a full record of calibrated temperature and date/time for each minilogger file supplied. The Originator has supplied a full record of calibration temperature, pressure, conductivity, salinity and date/time for each MicroCAT and SEACAT file supplied.

The depth of each logger and sea floor depth was estimated from two methods. The pressure/depth record from the nearest or most appropriate MicroCAT or ADCP and the log sheets of planned and actual instrument depths and/or separations (relative to a subsurface float).

ST1 inline mooring - Pressure readings from the MicroCATs on the ST1 chain were within 0.25db of each other pre and post deployment. No adjustments were made. The ADCP pressure readings were noisy and therefore the Originator did not use this as a reference point.

ST2 inline mooring - Pressure readings from the MicroCATs on this chain were within 0.2 db of each other pre and post deployment. No adjustments were made.

ST3 Bedframe mooring - The SBE16+ SEACAT CTD Serial No 4848 was deployed at station 3. The originator has indicated that offsets have been applied where large instabilities were seen in the data.

ST4 inline mooring - Pressure readings from all MicroCATs on the ST4 chain were within 0.15 db and 0.2 db of each other immediately before and after deployment respectively. No adjustments were made.

ST4 Bedframe mooring - The SBE 37 SM MicroCAT Serial No 4550 was deployed at station 4. The originator has indicated that offsets have been applied where large instabilities were seen in the data.

ST5 inline mooring - Pressure readings from the MicroCATs on this chain were within 0.2-0.25db of each other pre and post deployment. No adjustments were made.

ST5 Bedframe mooring - The SBE 37 SMP MicroCAT Serial No 7769 was deployed at station 5. The originator has indicated that offsets have been applied where large instabilities were seen in the data.

Field Calibrations

All DST Centi Loggers (CT) and Starmon Miniloggers (SM) have been calibrated against CTD casts 60 and 61. These calibrations were performed following recovery of the short term moorings.

All Vemco Miniloggers (ML) were calibrated using the bath calibration performed in a temperature controlled bath before the cruise.

The pressure, temperature and conductivity recorded by the MicroCATs and SEACATs were compared immediately before and after deployment to assess any significant offsets needing correction.

The originator states it was not possible to remove all the smaller scale instances of thermal instability and therefore has been left to the end user to make any further corrections (or removal of data) that are appropriate for the type of analysis they wish to perform.

The Originator has created four gridded data sets of temperature and pressure corresponding to the short term moorings ST1, ST2, ST4 and ST5 using a mixture of Starmon mini loggers (SM), DST Centi loggers (CT),Vemco loggers (ML) and MicroCATs (MC). These gridded data sets have been linearly interpolated onto a one minute grid. The gridded data has not been included but is available from BODC at request.

The Originator has informed BODC that some Vemco miniloggers had a smaller memory and were therefore set to a lower sampling rate.

Processing by BODC of RRS Discovery 376 short term mooring data

Data from three types of temperature loggers (DST Centi loggers, Vemco loggers and Starmon mini loggers) arrived at BODC in matlab files. This includes 28 DST Centi logger matlab files, 35 Vemco logger matlab files and 36 Starmon mini loggers matlab files with one file for each sensor used. The following table shows how the variables within the files were mapped to appropriate BODC parameter codes:

The reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag, missing data by both setting the data to an appropriate value and setting the quality control flag. The data files have been modified to remove data points that were gathered when the instruments were being deployed and recovered. These data points were deemed unstable by the Originator.

General Data Screening carried out by BODC

BODC screen both the series header qualifying information and the parameter values in the data cycles themselves.

Header information is inspected for:

• Irregularities such as unfeasible values
• Inconsistencies between related information, for example:
  • Times for instrument deployment and for start/end of data series
  • Length of record and the number of data cycles/cycle interval
  • Parameters expected and the parameters actually present in the data cycles
• Originator's comments on meter/mooring performance and data quality

Documents are written by BODC highlighting irregularities which cannot be resolved.

Data cycles are inspected using time or depth series plots of all parameters. Currents are additionally inspected using vector scatter plots and time series plots of North and East velocity components. These presentations undergo intrinsic and extrinsic screening to detect infeasible values within the data cycles themselves and inconsistencies as seen when comparing characteristics of adjacent data sets displaced with respect to depth, position or time. Values suspected of being of non-oceanographic origin may be tagged with the BODC flag denoting suspect value; the data values will not be altered.

The following types of irregularity, each relying on visual detection in the plot, are amongst those which may be flagged as suspect:

• Spurious data at the start or end of the record.
• Obvious spikes occurring in periods free from meteorological disturbance.
• A sequence of constant values in consecutive data cycles.

If a large percentage of the data is affected by irregularities then a Problem Report will be written rather than flagging the individual suspect values. Problem Reports are also used to highlight irregularities seen in the graphical data presentations.

Inconsistencies between the characteristics of the data set and those of its neighbours are sought and, where necessary, documented. This covers inconsistencies such as the following:

• Maximum and minimum values of parameters (spikes excluded).
• The occurrence of meteorological events.

This intrinsic and extrinsic screening of the parameter values seeks to confirm the qualifying information and the source laboratory's comments on the series. In screening and collating information, every care is taken to ensure that errors of BODC making are not introduced.

Project Information

Fluxes Across Sloping Topography of the North East Atlantic (FASTNEt)

Background

The FASTNEt consortium was funded to deliver NERC's Ocean Shelf Edge Exchange Programme. Commencing in October 2011, this four year study aims to couple established observational techniques, such as moorings and CTDs, with the very latest in autonomous sampling initiatives - including use of Autosub Long Range and gliders. With the aid of novel model techniques, these observations will be utilised to construct a new paradigm of Ocean/Shelf exchange.

Shelf edge regions mark the gateway between the world's deep oceans and shallower coastal seas, linking terrestrial, atmospheric and oceanic carbon pools and influencing biogeochemical fluxes. Shelf edge processes can influence near-shore productivity (and fisheries) and ultimately affect global climate.

FASTNEt brings together researchers from multiple UK organisations. Further collaboration has been established with five Project Partners: the UK Met Office, Marine Scotland Science, Agri-Food and Biosciences Institute, Marine Institute Ireland and Scripps Institution of Oceanography.

Scientific Objectives

• To determine the seasonality of physical gradients and exchange across the shelf edge by deploying new observational technologies (gliders, Autosub Long Range) and established techniques (long term moorings, drifters)
• To quantify key exchange mechanisms and to collect new data targeted at testing and improving high resolution models of the shelf edge, by carrying out detailed process studies in contrasting regions of the shelf edge of the NE Atlantic margin
• To develop a new parameterisation of shelf edge exchange processes suitable for regional-scale models, using improved resolution numerical, and new empirical models constrained by the observations
• To test the new parameterisations in a regional model in the context of making an assessment of inter-annual variability of ocean-shelf exchange.

Fieldwork

Three survey sites on the UK shelf edge have been selected for FASTNEt. These are a) the Celtic Sea shelf edge, b) Malin shelf and c) North Scotland shelf. Fieldwork is centred around two research cruises. The first, to the Celtic Sea, on RRS Discovery in June 2012. The second cruise visits the Malin shelf on RRS James Cook, during summer 2013. In addition to these dedicated cruises, opportunist cruise activity to the North Scotland shelf has been agreed with project partner Marine Scotland Science. Autonomous technologies will complement observations made during the cruises and provide knowledge of seasonal and inter-annual variability in exchange processes.

Instrumentation

Types of instruments/measurements:

• Gliders
• Autosub Long Range
• Drifter buoys
• Scanfish
• Microstructure profilers
• Moored CTD/CT loggers and ADCPs
• Shipboard measurements: CTD, underway, nutrients (and other discrete sampling), LADCP, ADCP.

Contacts

Data Activity or Cruise Information

Data Activity

FASTNEt single point mooring ST1

The short term mooring ST1 was deployed and recovered during cruise RRS Discovery D376 which took place between 11 June 2012 to 2 July 2012 as part of the Fluxes Across the Sloping Topography of the North East Atlantic (FASTNEt) project.

The mooring was kept upright by a large sub-surface float (at 31 m depth), supplemented by groups of deeper smaller buoys. The mooring incorporated a pellet at 15 m depth.

Instruments deployed on the mooring

Instrument codes

AC - 75 kHz RDI ADCP

CT - Star-Oddi DST centi-T Temperature Recorder

MC - SBE 37 MicroCAT

ML - Vemco Minilogger

Bad data were produced by Vemco Miniloggers 1087, 1106, 3894, 5593 and 6177 and so were not taken through by the Originator.

Related Data Activity activities are detailed in Appendix 1

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:

Appendix 1: ST1

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.