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Metadata Report for BODC Series Reference Number 1210842


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
NameCategories
WET Labs {Sea-Bird WETLabs} ECO FLNTU combined fluorometer and turbidity sensor  fluorometers; optical backscatter sensors
Sea-Bird SBE 19plus V2 SEACAT CTD  CTD; water temperature sensor; salinity sensor
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 NM05/13/81
BODC Series Reference 1210842
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2013-05-11 05:55
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval 1.0 decibars
 

Spatial Co-ordinates

Latitude 56.29483 N ( 56° 17.7' N )
Longitude 2.46767 W ( 2° 28.1' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth 1.98 m
Maximum Sensor or Sampling Depth 48.55 m
Minimum Sensor or Sampling Height 3.45 m
Maximum Sensor or Sampling Height 50.02 m
Sea Floor Depth 52.0 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
 

Parameters

BODC CODERankUnitsTitle
ACYCAA011DimensionlessSequence number
CNDCST011Siemens per metreElectrical conductivity of the water body by CTD
CPHLPS011Milligrams 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 and calibration against sample data
POTMCV011Degrees CelsiusPotential temperature of the water body by computation using UNESCO 1983 algorithm
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


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

FRV Alba na Mara 0313A, 0513A, and 0813A CTD Instrument Description

Sampling Strategy

CTD casts were carried out on cruises FRV Alba na Mara 0313A, FRV Alba na Mara 0513A, and FRV Alba na Mara 0813A using the instrumentation detailed below.

Unit Model Serial # Calibration Date (YYYY-MM-DD)
Pressure Sea-Bird SBE 19plus V2 SEACAT CTD 6029 2012-09-26
Temperature Sea-Bird SBE 19plus V2 SEACAT CTD 6029 2012-09-28
Conductivity Sea-Bird SBE 19plus V2 SEACAT CTD 6029 2012-09-28
Fluorometer WET Labs ECO FLNTU 0947 2008-03-05

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.

Specifications

Parameter SBE 19 SBE 19plus
Temperature

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*

Conductivity

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

Specifications

Temperature range 0 to 30°C
Depth rating

600 m (standard)

6000 m (deep)

Turbidity
Wavelength 700 nm
Sensitivity 0.01 NTU
Typical range 0.01 to 25 NTU
Fluorescence
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.

Processing by BODC of FRV Alba na Mara cruises 0313A, 0513A, and 0813A CTD data.

The data arrived at BODC in 3 concatenated ASCII format files representing cruises FRV Scotia 0313A (34 casts), 0513A (55 casts) and 0813A (49 casts).

The concatenated files were sub-divided into individual files for each cast using BODC in house Matlab software, and then reformatted to the internal BODC format.

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)/10.
Field samples for calibration were also taken during the cruise but not applied by the Originator. BODC has applied this calibration.
Fluorescence* µg l-1 Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate phase] by in-situ chlorophyll fluorometer. CPHLPS01 mg m-3 Field samples for calibration were taken during the cruise but not applied by the Originator. BODC has applied this calibration.
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) method.
- - 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) method.
Temperature (pri) Centigrade Unadjusted temperature data - - 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 - - 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 - - Secondary Temperature
Conductivity (sec) mS cm-1 No data supplied - - Secondary Conductivity

* Originators variable name is Fluorescence but BODC have identified that the data have had manufacturer's calibrations applied and are therefore chlorophyll values.

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.

Reference

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

Processing by Originator of FRV Alba na Mara 0513A CTD data

Sampling Strategy

Marine Scotland performed 55 CTD casts during cruise FRV Alba Na Mara 0513A as part of ongoing research funded by the Scottish Government and with an aim to inform the PICMATOP research project.

A Seabird CTD was deployed at stations in the Wee Bankie and Marr Bank areas, off the coast of Edinburgh in the North Sea with the ship departed Fraserburgh on 24 April 2013 and returned to dock on 13 May 2013.

A SBE35 carousel was attached to the CTD and was used to collect all 54 water samples taken during the cruise.

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 and the primary temperature and conductivity channels were adjusted to produce 'edit' channels. Marine Scotland regards the 'edit' channels 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

Conductivity

Marine Scotland used 54 water samples collected by the SBE35 carousel to generate a calibration equation as follows:

calibrated conductivity (mS cm-1) = measured conductivity x 1.005402 - 0.178519.

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

Fluorescence

Marine Scotland used 54 water samples collected by the SBE35 carousel to generate a calibration equation as follows:

Calibrated fluorescence (µg l-1) = measured fluorescence x 0.000969 + 0.124801.

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

Reference

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


Project Information


No Project Information held for the Series

Data Activity or Cruise Information

Cruise

Cruise Name 0513A
Departure Date 2013-04-25
Arrival Date 2013-05-13
Principal Scientist(s)Philip Boulcott (Marine Scotland Aberdeen Marine Laboratory)
Ship FRV Alba Na Mara

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