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Metadata Report for BODC Series Reference Number 1184409

Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
Sea-Bird SBE 19plus SEACAT CTD  CTD; water temperature sensor; salinity sensor
WET Labs {Sea-Bird WETLabs} ECO FLNTU combined fluorometer and turbidity sensor  fluorometers; optical backscatter sensors
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Mr George Slesser
Originating Organization Marine Scotland Aberdeen Marine Laboratory
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) -

Data Identifiers

Originator's Identifier SC16/12/531
BODC Series Reference 1184409

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2012-11-26 07:41
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval 1.0 decibars

Spatial Co-ordinates

Latitude 55.63150 N ( 55° 37.9' N )
Longitude 8.41167 W ( 8° 24.7' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth 2.97 m
Maximum Sensor or Sampling Depth 83.22 m
Minimum Sensor or Sampling Height 4.78 m
Maximum Sensor or Sampling Height 85.03 m
Sea Floor Depth 88.0 m
Sea Floor Depth Source DATAHEAD
Sensor or Sampling Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor or Sampling Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface


BODC CODERankUnitsTitle
ACYCAA011DimensionlessSequence number
CNDCST011Siemens per metreElectrical conductivity of the water body by CTD
CPHLPR011Milligrams per cubic metreConcentration of chlorophyll-a {chl-a CAS 479-61-8} per unit volume of the water body [particulate >unknown phase] by in-situ chlorophyll fluorometer
PRESPR011DecibarsPressure (spatial coordinate) exerted by the water body by profiling pressure sensor and correction to read zero at sea level
PSALST011DimensionlessPractical salinity of the water body by CTD and computation using UNESCO 1983 algorithm
SIGTPR011Kilograms per cubic metreSigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm
TEMPST011Degrees CelsiusTemperature of the water body by CTD or STD
TURBPR011Nephelometric Turbidity UnitsTurbidity of water in the water body by in-situ optical backscatter measurement and laboratory calibration against formazin

Definition of Rank

  • Rank 1 is a one-dimensional parameter
  • Rank 2 is a two-dimensional parameter
  • Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

Problem Reports

No Problem Report Found in the Database

Quality report for FRV Scotia CTD 2012 chlorophyll data


A calibration generated by the Originator has been applied to the chlorophyll data which has lead, on occasion to negative values within the profiles. All the negative values have been flagged by BODC and should be considered as suspect and be used with caution.

Data Access Policy

Public domain 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.

The recommended acknowledgment is

"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."

Narrative Documents

CTD Instrument Description for FRV Scotia 0812S, 0912S, 1112S, 1412S and 1612S

Sampling Strategy

CTD casts were carried out on cruises FRV Scotia 0812S, FRV Scotia 0912S, FRV Scotia 1112S, FRV Scotia 1412S and FRV Scotia 1612S using the Sea-Bird SBE19plus V2 SEACAT. The instrumentation is detailed below.

CTD unit and auxiliary sensors Model Serial # Calibration Date (YYYY-MM-DD)
Pressure Sea-Bird SBE19plus V2 SEACAT 6028 2011-12-23
Temperature Sea-Bird SBE19plus V2 SEACAT 6028 2011-12-24
Conductivity Sea-Bird SBE19plus V2 SEACAT 6028 2011-12-24
Fluorometer Wet Labs ECO FLNTU 0942 2012-02-23

No changes to the CTD instrumentation were recorded during these cruises.

Sea-Bird SBE 19 and SBE 19plus SEACAT Profiler CTDs

The SBE 19 SEACAT Profiler is a self-contained, battery powered, pumped CTD system designed to measure conductivity, temperature, and pressure in marine or fresh water environments to depths of 10,500 meters. It was replaced by the SBE 19plus model in 2001. An updated version of this instrument is the SBE 19plus V2, which incorporates an electronics upgrade and additional features, with six differentially amplified A/D input channels, one RS-232 data input channel, and 64 MB FLASH memory.

The standard CTD unit comes with a plastic housing (rated to 600 m), although this can be replaced by titanium housing for depths up to 7000 m. It is typically used for CTD profiling although a conversion kit is available for mooring deployments. The CTD can also be attached to an SBE 36 CTD Deck Unit and Power/Data Interface Module (PDIM) for real-time operation on single-core armored cable up to 10,000 m.


Parameter SBE 19 SBE 19plus

Range: -5 to +35 °C

Accuracy: 0.01 °C

Resolution: 0.001 °C

Calibration: +1 to +32 °C*

Range: -5 to +35 °C

Accuracy: 0.005 °C

Resolution: 0.0001 °C

Calibration: +1 to +32 °C*


Range: 0 to 7 S m-1 (0 to 70 mmho cm-1)

Accuracy: 0.001 S m-1

Resolution: 0.0001 S m-1

Calibration: 0 to 7 S m-1. Physical calibration over the range 1.4 - 6 S m-1*

Range: 0 to 9 Sm-1

Accuracy: 0.0005

Resolution: 0.00005 (most oceanic waters, resolves 0.4 ppm in salinity); 0.00007 (high salinity waters, resolves 0.4 ppm in salinity); 0.00001 (fresh waters, resolves 0.1 ppm in salinity)

Calibration: 0 to 9 S m-1. Physical calibration over the range 1.4 - 6 S m-1*

Strain gauge pressure sensor

Range: 0 to100, 150, 300, 500, 1000, 1500, 3000, 5000, 10000 or 15000 psia

Accuracy: 0.25% of full scale range (100 - 1500 psia); 0.15% of full scale range (3000 - 15000 psia)

Resolution: 0.015% of full scale

Calibration: 0 to full scale in 20% steps

Range: 0 to 20, 100, 350, 1000, 2000, 3500 or 7000 m

Accuracy: 0.1% of full scale range

Resolution: 0.002% of full scale range

Calibration: ambient pressure to full scale range in 5 steps

*Measurements outside this range may be at slightly reduced accuracy due to extrapolation errors.

Options and accessories

Additional sensors can be attached to the CTD, including:

  • high accuracy Paroscientific Digiquartz pressure sensor (depth range 0 to 20, 60, 130, 200, 270, 680, 1400, 2000, 4200, 7000 or 10500 m; accuracy 0.02% of full scale; resolution 0.0025% of full scale)
  • 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 standard SBE 5M pump may be replaced by an SBE 5P (plastic housing) or 5T (titanium housing) pump for use with dissolved oxygen and/or other pumped sensors. Further details can be found in the manufacturer's SBE 19plus V2 instrument specification or theSBE 19 andSBE 19 plus user guides.

WETLabs ECO FLNTU fluorescence and turbidity sensor

The Environmental Characterization Optics (ECO) Fluorometer and Turbidity (FLNTU) sensor is a dual wavelength, single-angle instrument that simultaneously determines chlorophyll fluorescence and turbidity. It is easily integrated in CTD packages and provides a reliable turbidity measurement that is not affected by Colored Dissolved Organic Matter (CDOM) concentration.

The FLNTU can operate continuously or periodically and has two different types of connectors to output the data. There are 5 other models that operate the same way as this instrument but have slight differences, as stated below:

  • FLNTU(RT) - has an analog an RS-232 serial output and operates continuously, when power is supplied
  • FLNTU(RT)D - similar to the FLNTU(RT) but has a depth rating of 6000 m
  • FLNTUB - has internal batteries for autonomous operation
  • FLNTUS - has an integrated anti-fouling bio-wiper
  • FLNTUSB - has the same characteristics as the FLNTUS but with internal batteries for autonomous operation


Temperature range 0 to 30°C
Depth rating

600 m (standard)

6000 m (deep)

Wavelength 700 nm
Sensitivity 0.01 NTU
Typical range 0.01 to 25 NTU
Wavelength 470 nm (excitation), 695 nm (emission)
Sensitivity 0.01 µg L-1
Typical range 0.01 to 50 µg L-1
Linearity 99% R2

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

BODC CTD Screening

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 infeasible values
  • Inconsistencies between related information. For example:
    • Deepest CTD data cycle is significantly greater than the depth of the sea floor.
    • Times of the cruise and the start/end of the data series.
    • Length of the record, number of data cycles, cycle interval, clock error and the period over which data were collected.
    • Parameters stated as measured and the parameters actually present in the data series.
  • Originator's comments on instrument/sampling device performance and data quality.

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

Data cycles are inspected using depth series plots of all parameters. These presentations undergo screening to detect infeasible values within the data cycles themselves and inconsistencies when comparing 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 following types of irregularity, each relying on visual detection in the time series plot, are amongst those that may be flagged as suspect:

  • Spurious data at the start or end of the record where the instrument was recording in air
  • Obvious spikes occurring in the data due electrical problems
  • Constant, or near-constant, data channels

If a large percentage of the data is affected by irregularities, deemed abnormal, then instead of flagging the individual suspect values, a caution may be documented.

The following types of inconsistency are detected automatically by software:

  • Data points with values outside the expected range for the parameter, as defined by the BODC parameter usage vocabulary.

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

  • Maximum and minimum values of parameters (spikes excluded).
  • Anomalous readings due to the CTD package being bounced through temperature and/or salinity gradients.

This 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's making are not introduced.

FRV Scotia 1612S CTD Originator's data processing

Sampling Strategy

A total of 55 CTD casts were performed by Marine Scotland as part of on going research funded by the Scottish Government, between 17 November 2012 and 3 December 2012 during cruise FRV Scotia1612S. Casts were deployed off the west coast of Orkney in the North Sea and to the north of the Minch and to the north of Lewis, in the Atlantic Ocean. Further casts were performed to the south west to Stanton Banks and off the west coast of Ireland. Casts were then deployed around the north coast of Ireland and in the Clyde area before the cruise terminated in the Hebrides.

A Knudsen reversing bottle attached to a wire 1 m above the CTD was fired for every cast.

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. The primary temperature and conductivity channels were adjusted to produce 'edit' channels which Marine Scotland regards 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). The time was recorded in UTC.

Field Calibrations


A total of 50 water samples were taken by Marine scotland using the Knudsen reversing bottle mentioned above to provide a calibration equation for conductivity as follows:

calibrated conductivity (mS cm-1) = measured conductivity x 0.994999 + 0.199376.

The calibration was not applied to the data by the Originator.


Marine Scotland examined the latest and the previous manufacturer's calibrations to look at the differences in the temperature recorded. There were no significant differences and therefore Marine Scotland concluded that no further calibrations needed to be undertaken.


Marine Scotland carried out a check using CTD data from a prior cruise where the CTD was used to look for any noticeable change in the sensors performance and concluded that no calibration were needed for the fluorescence data.


Sy A., 1985. An alternative editing technique for oceanographic data. Deep Sea Research, 32 (12), 1591-1599,

Processing by BODC of FRV Scotia cruises 0212S, 0312S, 0812S,0912S, 1112S,1412S and 1612S CTD data

The data arrived at BODC in 7 concatenated ASCII format files representing cruises FRV Scotia 0212S (56 casts), 0312S (63 casts), 0812S (41 casts), 0912S (85 casts), 1112S (20 casts), 1412S (4 casts) and 1612S (55 casts). The concatenated files were sub-divided into individual files for each cast, using BODC in house Matlab software. These were reformatted to the internal BODC format using transfer function 340. The following table shows how the variables within the files were mapped to appropriate BODC parameter codes:

Originator's Variable Units Description BODC Parameter Code Units Comment
Pressure dbar Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level PRESPR01 dbar -
Temperature (edit) Centigrade Temperature of the water body by CTD or STD TEMPST01 °C Celsius = Centigrade
Conductivity (edit) mS cm-1 Electrical conductivity of the water body by CTD CNDCST01 S m-1 Conversion of Originators units to BODC units: conductivity(edit) * 0.1. BODC applied Originator calibration during transfer
Temperature (pri) Centigrade Unadjusted temperature data N/A N/A Primary Temperature. Data were not loaded by BODC as Originator stated Temperature (edit) channel was a quality controlled version of the primary channel
Conductivity (pri) mS cm-1 Unadjusted conductivity data N/A N/A Primary Conductivity. Data were not loaded by BODC as Originator stated Conductivity (edit) channel was a quality controlled version of the primary channel
Temperature (sec) Centigrade No data supplied N/A N/A Secondary Temperature
Conductivity (sec) mS cm-1 No data supplied N/A N/A Secondary Conductivity
Fluorescence µg l-1 Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate phase] by in-situ chlorophyll fluorometer. CPHLPR01 mg m-3 No field calibrations
Turbidity NTU Turbidity of the water body by in-situ optical backscatter measurement and laboratory calibration against formazin TURBPR01 NTU -
- - Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm PSALST01 Dimensionless Derived from TEMPST01 and CNDCST01 in transfer using Fofonoff and Millard (1983).
- - Sigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm SIGTPR01 kg m-3 Derived from PSALST01, TEMPST01 and PRESPR01 in transfer using Fofonoff and Millard (1983).

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.


Fofonoff, P., Millard Jr, R.C., 1983. Algorithms for computation of fundamental properties of seawater.Unesco Technical Papers in Marine Sciences 44, 53 pp.

Project Information

No Project Information held for the Series

Data Activity or Cruise Information


Cruise Name 1612S
Departure Date 2012-11-13
Arrival Date 2012-12-04
Principal Scientist(s)Craig G Davis (Marine Scotland Aberdeen Marine Laboratory)
Ship FRV Scotia

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