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Metadata Report for BODC Series Reference Number 632659


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
NameCategories
Sea-Bird SBE 25 Sealogger CTD  CTD; water temperature sensor; salinity sensor
WET Labs {Sea-Bird WETLabs} C-Star transmissometer  transmissometers
WET Labs {Sea-Bird WETLabs} ECO FL fluorometer  fluorometers
Instrument Mounting research vessel
Originating Country United Kingdom
Originator Ms Sarah Hughes
Originating Organization Fisheries Research Services Aberdeen Marine Laboratory (now 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 SC18/03/761
BODC Series Reference 632659
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2003-12-17 01:44
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval 1.0 decibars
 

Spatial Co-ordinates

Latitude 58.75130 N ( 58° 45.1' N )
Longitude 0.00250 W ( 0° 0.1' W )
Positional Uncertainty Unspecified
Minimum Sensor or Sampling Depth 0.99 m
Maximum Sensor or Sampling Depth 144.59 m
Minimum Sensor or Sampling Height 2.4 m
Maximum Sensor or Sampling Height 146.01 m
Sea Floor Depth 147.0 m
Sea Floor Depth Source -
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
ATTNZS011per metreAttenuation (red light wavelength) per unit length of the water body by WET Labs transmissometer and calibration to read zero in clear water
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
FVLTWS011VoltsRaw signal (voltage) of instrument output by linear-response 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
SIGTEQ011Kilograms per cubic metreSigma-theta of the water body by computation from salinity and potential temperature using UNESCO algorithm
TEMPST011Degrees CelsiusTemperature of the water body by CTD or STD

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

Sea-Bird SBE 25 SEALOGGER CTD

The SBE 25 SEALOGGER is a research-quality CTD profiling system used for coastal, estuarine and, can also be a practical option, for deep-water work. It is easily configured in the field for a wide range of auxiliary sensors. The SEALOGGER is self-powered, requires no conductive cable, and is designed for use up to 6800 meters (10,000 psia). It uses the SBE3F temperature and SBE4 conductivity sensors as well as having an external strain gauge pressure sensor. It provides pump-controlled T-C ducted flow, samples at 8 Hz, records internally and provides simultaneous real-time data via its built-in RS-232 interface.

The standard CTD unit comes with a plastic housing (rated to 600 m), although this can be replaced by aluminium housing for depths up to 6800 m.

Specifications

Parameter SBE 25
Temperature

Range: -5 to +35 °C

Accuracy: 0.002 °C

Resolution: 0.0003 °C

Conductivity

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

Accuracy: 0.0003 S m-1

Resolution: 0.00004 S m-1

Strain gauge pressure sensor

Range: 0 to 20, 100, 350, 600, 1000, 2000, 3500, 7000 metres (expressed in metres of deployment depth capability)

Accuracy: 0.1% of full scale range

Resolution: 0.015% of full scale range

Options and accessories

Additional sensors can be attached to the CTD, including:

  • 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 SBE 5T titanium pump can be used in place of SBE 5P pump. Further details can be found in the manufacturer's SBE 25 instrument specification.

WETLabs ECO-FL Fluorometer

The Environmental Characterization Optics series of single channel fluorometers are designed to measure concentrations of natural and synthetic substances in water, and are therefore useful for biological monitoring and dye trace studies. Selected excitation and emission filters allow detection of the following substances: chlorophyll-a, coloured dissolved organic matter (CDOM), uranine (fluorescein), rhodamine, phycoerythrin and phycocyanin.

The ECO-FL can operate continuously or periodically and has two different types of connectors to output the data (analogue and RS-232 serial output). The potted optics block results in long term stability of the instrument and the optional anti-biofouling technology delivers truly long term field measurements.

In addition to the standard model, five variants are available, and the differences between these and the basic ECO-FL are listed below:

  • FL(RT): similar to the FL but operates continuously when power is supplied
  • FL(RT)D: similar model to the (RT) but has a depth rating of 6000 m
  • FLB: includes internal batteries for autonomous operation and periodic sampling
  • FLS: similar to FLB but has an integrated anti-fouling bio-wiper
  • FLSB: similar to the FLS, but includes internal batteries for autonomous operation

Specifications

Temperature range 0 to 30°C
Depth rating

600 m (standard)

6000 m (deep)

Linearity 99 % R2
Chlorophyll-a
Wavelength (excitation/emission) 470/695 nm
Sensitivity 0.01 µg L-1
Typical range 0.01 to 125 µg L-1
CDOM
Wavelength (excitation/emission) 370/460 nm
Sensitivity 0.01 ppb
Typical range 0.09 to 500 ppb
Uranine
Wavelength (excitation/emission) 470/530 nm
Sensitivity 0.07 ppb
Typical range 0.12 to 230 ppb
Rhodamine
Wavelength (excitation/emission) 540/570 nm
Sensitivity 0.01 ppb
Typical range 0.01 to 230 ppb
Phycoerythrin
Wavelength (excitation/emission) 540/570 nm
Sensitivity 0.01 ppb
Typical range 0.01 to 230 ppb
Phycocyanin
Wavelength (excitation/emission) 630/680 nm
Sensitivity 0.15 ppt
Typical range 0.15 to 400 ppt

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

WETLabs C-Star transmissometer

This instrument is designed to measure beam transmittance by submersion or with an optional flow tube for pumped applications. It can be used in profiles, moorings or as part of an underway system.

Two models are available, a 25 cm pathlength, which can be built in aluminum or co-polymer, and a 10 cm pathlength with a plastic housing. Both have an analog output, but a digital model is also available.

This instrument has been updated to provide a high resolution RS232 data output, while maintaining the same design and characteristics.

Specifications

Pathlength 10 or 25 cm
Wavelength 370, 470, 530 or 660 nm
Bandwidth

~ 20 nm for wavelengths of 470, 530 and 660 nm

~ 10 to 12 nm for a wavelength of 370 nm

Temperature error 0.02 % full scale °C-1
Temperature range 0 to 30°C
Rated depth

600 m (plastic housing)

6000 m (aluminum housing)

Further details are available in the manufacturer's specification sheet or user guide.

RV Scotia 18/2003 CTD Data Documentation

Instrumentation

The instrument used was a Sea-Bird SBE25 Sealogger.

Details of the sensors on the CTD are -

Manufacturer Sensor Serial No. Manufacturer Cal. Date Sensor Units
Sea-Bird Pressure 051128 13 Mar 2003 Decibars
Sea-Bird Temperature 1696 14 Feb 2003 Centigrade
Sea-Bird Conductivity 1454 13 Feb 2003 Siemens/meter
Wet Labs Fluorometer FLRTD-064 11 Aug 2003 Volts
Wet Labs Transmissometer CST-704DR 25 Aug 2003 Volts

Calibrations

Parameter Value of m (y=mx+c) Value of c (y=mx+c) Equation
Pressure 1.000000 0.000000 P(cal) = P(obs)
Temperature 1.000000 0.000000 T(cal) = T(obs)
Conductivity 0.999949 -0.000499 C(cal) = 0.999949C(obs) + -0.000499
Fluorescence 0.000286 0.094749 Chlor.(cal) (ug/L) = 0.000286F(obs) (V) + 0.094749
Beam Attenuation 1.000000 0.000000 B(cal) = B(obs)

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


No Project Information held for the Series

Data Activity or Cruise Information

Cruise

Cruise Name 1803S
Departure Date 2003-12-08
Arrival Date 2003-12-21
Principal Scientist(s)John Dunn (Fisheries Research Services 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