Metadata Report for BODC Series Reference Number 1217785
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
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Problem Reports
Transect L
The Originator has indicated that all data collected from transect L (17 June 2012) are of very low quality due to instrument failure.
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
D376 Scanfish Instrumentation
CTD unit and auxiliary sensors
The scanfish CTD was deployed with a Falmouth Scientific Instruments (FSI) CTD unit in addition to a Haardt Fluorometer and AANDERAA CTD sensors. The table below shows relevant sensor information where possible.
Sensor | Serial Number | Last calibration date |
---|---|---|
Primary Temperature Sensor | ATB - 1250 | 5 November 2005 |
Primary Conductivity Sensor | ATB - 1250 | 5 November 2005 |
Primary Pressure Sensor | - | 5 November 2005 |
Haardt Fluorometer (model unknown) | - | - |
Falmouth Scientific NXIC CTD Series
The FSI NXIC CTD Series is a collection of rugged Conductivity-Temperature-Depth profilers that utilise the patented Non-eXternal Inductive Cell (NXIC) conductivity sensor, which was originally developed for the US Navy DT-705 Sound Velocity/Salinity sensor. The CTDs are fast sampling, fully integrated instruments with optional battery power, datalogging and external analog sensor input.
Models in the collection include the NXIC CT Bio Direct Read-500M, NXIC CTD Bio Direct Read-500M, NXIC CTD Bio Auto-500M, NXIC CTD Direct Read-500M, NXIC CTD Direct Read-700M, NXIC CTD Auto-500M, NXIC CTD Auto-700M, NXIC CTD-ADC with external sensors, and the NXIC ETSG Thermosalinograph. Parameters are measured to an accuracy ranging from 0.002-0.010 mS/cm for conductivity, 0.005 degC for temperature and 0.08% for full scale pressure. Now marketed by Teledyne RD Instruments.
Specifications
Conductivity | Temperature | Pressure | |
---|---|---|---|
Sensor type | Inductive cell | Thermistor | Precision-machined Silicon |
Range | 0 to 9.0 S m-1 | -5 to 45°C | user specified |
Accuracy | ± 0.0002 S m-1 | ± 0.005°C | 0.08 % full scale |
Stability | ± 0.00005 S cm-1 month-1 | 0.0005°C month-1 | ± 0.004 % |
Resolution | 0.00001 S m-1 | 0.001°C | 0.001 % full scale |
Response | 5.0 cm at 1 m sec-1 flow | 100 msec | 25 msec |
Further details can be found in the manufacturer's specification sheet and Series Brochure.
D376 Scanfish Originator Processing
Sampling Strategy
The RSS 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. Led by the Scottish Association for Marine Science, D376 was a 19 day cruise setting sail from Swansea on 11 June 2012 to the Celtic Sea shelf edge and returning to Southampton on 2 July 2012.
A total of 5 Scanfish tow-yo surveys were conducted during the cruise D376 details of which can be found in the following table:
Originator' identifier | Date of deployment | Location | Comments |
---|---|---|---|
L | 17 June 2012 | Transect from the Shelf Break to Jones Bank | Data from this transect were corrupted due to a cable malfunction and was not used for any further analysis by the Originator |
R | 19 June 2012 | Repletion transect on a lattice at the middle of L transect at the center of Celtic sea shelf south-west of Jones Bank | - |
C | 23 June 2012 | Transect across Petit-Sole Canyon near the Shelf Break | - |
Z | 25 June 2012 | Transect over Shelf Break and canyon area | The date/time stamps and the coordinates data corrupted, both were recoverable from the ship navigation system |
B | 30 June 2012 | Transect from the Shelf Break to Jones Bank | - |
Throughout the cruise the Scanfish was generally 'flown' at a tow speed of 7.5 - 8.0 knots, 550 m behind the ship from depths of 1-5 m below the surface to 100-120 m, with a cycling time of every 2 minutes. In the shallower parts of the transect the Scanfish was kept within 10 m of the sea bed.
Data Processing
All raw Scanfish CTD profiles were acquired with CTD Acq-DT application Version 3.56 and were processed during the cruise with Citadel CTD Post Processing Version 3.57 software to produce Ascii files. The ascii files have been de-spiked by the originator against main outliers.
The original CTD data was combined with ship navigation data to provide accurate information on vertical distribution of the water parameters, and to calculate its position in the water using the ship as a reference.
References
Inall et al., (2012) 'RSS Discovery Cruise D376 Swansea to Southampton FASNTNEt Cruise to the Celtic Sea Shelf Edge', Internal Report No 277, Scottish Association for Marine Science.
Available - Cruise D376 Internal Report
D376 Scanfish Processing undertaken by BODC
Data arrived at BODC in a total of 12 matlab files representing data collected from 5 SCANFISH transect's conducted during D376. These were reformatted to BODC's internal QXF format.
The following table shows the mapping of variables within the ASCII files to appropriate BODC parameter codes:
Originator' Variable | Units | Description | BODC Parameter Code | Units | Comments |
---|---|---|---|---|---|
Pressure | db | Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level | PRESPR01 | dbar | - |
Temperature | °C | Temperature of water body | TEMPPR01 | °C | - |
Conductivity | S/m | Electrical conductivity of water body by in-situ conductivity cell | CNDCPR01 | S/m | - |
Salinity | - | Practical salinity of the water body by conductivity cell and computation using UNESCO 1983 algorithm | PSALPR01 | - | - |
Fluorescence Counts | - | Instrument output (counts) by in-situ chlorophyll fluorometer | FCNTRW01 | - | - |
Fluorescence | µg l | Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate >unknown phase] by in-situ chlorophyll fluorometer | CPHLPR01 | mg/m3 | - |
Distance run | km | Distance travelled | DSRNCV01 | km | - |
Latitude | deg | Latitude north (WGS84) by unspecified GPS system | ALATGP01 | deg | - |
Longitude | deg | Longitude east (WGS84) by unspecified GPS system | ALONGP01 | deg | - |
- | - | Potential temperature of the water body by computation using UNESCO 1983 algorithm | POTMCV01 | °C | Derived from PSALPR01, TEMPPR01 and PRESPR01 in transfer using Fofonoff and Millard (1983) method. |
- | - | Sigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm | SIGTPR01 | Kg/m3 | Derived from PSALPR01, TEMPPR01 and PRESPR01 in transfer using Fofonoff and Millard (1983) method. |
The reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag, and missing data marked by both setting the data to an appropriate value and setting the quality control flag.
Additional data held at BODC
In addition to the above, BODC also hold a higher resolution version of this dataset of approximately 25 frames per second which have not undergone BODC processing or quality control.
Reference
Fofonoff, P., Millard Jr, R.C., 1983. Algorithms for computation of fundamental properties of seawater. Unesco Technical papers in Marine Science 44, 53pp.
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
Collaborator | Organisation |
---|---|
Prof. Mark Inall (lead) | Scottish Association for Marine Science, U.K |
Dr. Jason Holt | National Oceanography Centre, U.K |
Dr. Peter Miller | Plymouth Marine Laboratory, U.K |
Dr. Mattias Green | Bangor University, U.K |
Prof. Jonathan Sharples | University of Liverpool, U.K |
Dr. Vasyl Vlasenko | University of Plymouth, U.K |
Data Activity or Cruise Information
Cruise
Cruise Name | D376 |
Departure Date | 2012-06-11 |
Arrival Date | 2012-07-02 |
Principal Scientist(s) | Mark E Inall (Scottish Association for Marine Science) |
Ship | RRS Discovery |
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:
Flag | Description |
---|---|
Blank | Unqualified |
< | Below detection limit |
> | In excess of quoted value |
A | Taxonomic flag for affinis (aff.) |
B | Beginning of CTD Down/Up Cast |
C | Taxonomic flag for confer (cf.) |
D | Thermometric depth |
E | End of CTD Down/Up Cast |
G | Non-taxonomic biological characteristic uncertainty |
H | Extrapolated value |
I | Taxonomic flag for single species (sp.) |
K | Improbable value - unknown quality control source |
L | Improbable value - originator's quality control |
M | Improbable value - BODC quality control |
N | Null value |
O | Improbable value - user quality control |
P | Trace/calm |
Q | Indeterminate |
R | Replacement value |
S | Estimated value |
T | Interpolated value |
U | Uncalibrated |
W | Control value |
X | Excessive difference |
SeaDataNet Quality Control Flags
The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:
Flag | Description |
---|---|
0 | no quality control |
1 | good value |
2 | probably good value |
3 | probably bad value |
4 | bad value |
5 | changed value |
6 | value below detection |
7 | value in excess |
8 | interpolated value |
9 | missing value |
A | value phenomenon uncertain |
B | nominal value |
Q | value below limit of quantification |