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Metadata Report for BODC Series Reference Number 94847

Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
Bissett-Bermann 9040 CTD system  CTD; water temperature sensor; salinity sensor
Instrument Mounting research vessel
Originating Country United Kingdom
Originator -
Originating Organization Scottish Marine Biological Association (now Scottish Association for Marine Science)
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) -

Data Identifiers

Originator's Identifier C678/042
BODC Series Reference 94847

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1978-04-19 19:30
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -

Spatial Co-ordinates

Latitude 57.12330 N ( 57° 7.4' N )
Longitude 9.57160 W ( 9° 34.3' W )
Positional Uncertainty Unspecified
Minimum Sensor or Sampling Depth 5.55 m
Maximum Sensor or Sampling Depth 1866.45 m
Minimum Sensor or Sampling Height 63.54 m
Maximum Sensor or Sampling Height 1924.45 m
Sea Floor Depth 1930.0 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


BODC CODERankUnitsTitle
PRESPR011DecibarsPressure (spatial coordinate) exerted by the water body by profiling pressure sensor and correction to read zero at sea level
PSALPR011DimensionlessPractical salinity of the water body by conductivity cell and computation using UNESCO 1983 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

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

Bissett-Bermann 9040 Conductivity Temperature and Depth

The basic configuration of the B-B 9040 CTD incorporates pressure, temperature and conductivity sensors which could be logged digitally. This system also made it possible to derive other parameters, such as salinity, depth and sound velocity.

The instrument was versatile and it was possible to attach a dissolved oxygen sensor or to change the CTD housing, allowing it to obtain data from deeper layers in the water column. The accuracy for salinity is ±0.02 ppt , and ±0.02°C for temperature.

This instrument was also known as the Plessey 9040.

RRS Challenger 6/78 CTD Data Documentation


Documentation for the CTD data collected on RRS Challenger Cruise 6/78 (April 1978) by the Scottish Marine Biological Association, Oban, Argyll, Scotland, UK, under the direction of D. J. Ellett.

Note that no start time was given for cast C678/015 (BODC Series Reference 94534) - it has been set to 1000h to fit in with the preceding and following casts.

SMBA commented that C678/020, C678/022 (BODC Series Reference 94595 and 94614) - salinity from bottle samples doubtful.


The instrument used was a Bissett Berman 9040 CTD system and the data were logged on a Hewlett Packard 9820 and stored in an integer format. Instrument lowering and raising speeds were between 0.5 m/s and 1 m/s. An acoustic pinger was placed above the CTD to give an accurate depth measurement, this could then be used to check the CTD pressure calibration. An NIO bottle with reversing thermometers was placed above the pinger, within 2m of the CTD system. A bottle sample was taken at the bottom of the cast providing the temperature and salinity are uniform at that point. If large temperature or salinity gradients were present then the bottle sample was triggered at a suitable site on the upcast. A surface salinity sample was also taken at the start of the dip.


The CTD was not calibrated in the laboratory. The manufacturer's calibration was used and water samples taken to check the calibration and apply corrections where necessary.


The manufacturer's calibration was used to convert the raw data to physical units using the equation below:

Temperature (°C) = (106/Pt -2238.68/55.84)
where Pt is the temperature period in microseconds

These values were then plotted against the water bottle (i.e. reversing thermometer) temperatures and a regression line fitted to the data such that:

Temperature(WB) = m x Temperature(CTD) + c

Then the regression coefficients (m and c) were applied to correct the CTD temperature data - these are given in the table below.


The manufacturer's calibration was used to convert the raw data to physical units using the equation below:

Conductivity (mmho/cm) = (106/Pc - 4995)/58.12 + 10
where Pc is the conductivity period in microseconds

The water bottle salinities and corrected CTD temperatures were used to calculate the water bottle conductivity values. These values were then plotted against the CTD conductivities and a regression line fitted to the data such that:

Conductivity(WB) = m x Conductivity(CTD) + c

Then the regression coefficients were applied to correct the CTD conductivity data - these are given in the table below.


The depths from the acoustic pinger were noted where the bottle samples were taken and then used to check the calibration of the pressure sensor - unless calibration values were available from the reversing thermometers. The equation below was used to convert the pressure period to physical units.

Pressure = (106 /Pd - 9712)/0.26267
where Pd is the pressure period in microseconds

A regression fit was carried out using the calibration values and the slope and intercept determined. The pressure values could then be corrected using:

Pressure (CORR) = m x Pressure(CTD) + c

The fit of the CTD data to the water bottle calibration data is given in the table below:

Variable Slope (m) Intercept (c) Standard
Temperature (°C) 1.0018 0.0273 0.005
Conductivity (mmho/cm) 0.9968 0.1170 0.013
Pressure (dbar) 1.0037 -3.9436 3.450

Data Processing

Obvious wild points were edited out of the calibration file and the calibration programs run to obtain values for the slopes and intercepts for temperature, pressure and conductivity. These were then applied to the uncalibrated data. Conductivities were converted to conductivity ratios and then converted to salinities using UNESCO recommended routines and sigma-t was calculated. The data values were then sieved to ensure a minimum separation between pressure values of 1 dbar. The data were then visually inspected and major spikes flagged.


Sharples, F. (1987).
A new data bank of SMBA STD/CTD observations in the Rockall Trough 1975-84. SMBA Marine Physics Group Report No. 36.

Graham, J.M., Sharples, F., Meldrum, D.T. and Edwards, A. (1987).
STD observations in the Rockall Trough 1975-77. SMBA Marine Physics Group Report No. 39.

Fofonoff, N.P. and Millard Jr., R.C. (1983).
Algorithms for the computation of fundamental properties of sea water. UNESCO Technical Paper on Marine Science 44.

Project Information

No Project Information held for the Series

Data Activity or Cruise Information


Cruise Name CH6/78
Departure Date 1978-04-11
Arrival Date 1978-04-21
Principal Scientist(s)David J Ellett (Scottish Marine Biological Association)
Ship RRS Challenger

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Station NameDML Shelf Edge Station P1
CategoryOffshore location
Latitude57° 7.50' N
Longitude9° 33.50' W
Water depth below MSL1375.0 m

DML Shelf Edge Station P1

Shelf edge station P1 is a fixed CTD station on the shelf edge to the south east of the Anton Dohrn Seamount (west of Scotland). Station P1 was established by scientists at Dunstaffnage Marine Laboratory (DML) and acts as an additional site along the Ellett Line/Extended Ellett Line CTD sections.

Related Fixed Station activities are detailed in Appendix 1

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

Appendix 1: DML Shelf Edge Station P1

Related series for this Fixed Station 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.

Series IdentifierData CategoryStart date/timeStart positionCruise
187680CTD or STD cast1980-03-03 19:07:0057.1233 N, 9.5666 WRRS Challenger CH4/80
188972CTD or STD cast1980-05-05 02:30:0057.1216 N, 9.565 WRRS Challenger CH7/80
188984CTD or STD cast1980-05-05 04:05:0057.1 N, 9.57 WRRS Challenger CH7/80
312692CTD or STD cast1981-01-30 02:40:0057.125 N, 9.55 WRRS Challenger CH2/81
187864CTD or STD cast1981-04-13 02:22:0057.1233 N, 9.55 WRRS Challenger CH6A/81
192215CTD or STD cast1981-07-12 13:30:0057.1216 N, 9.5716 WRRS Challenger CH10/81
187201CTD or STD cast1981-10-17 02:05:0057.125 N, 9.5533 WRRS Challenger CH15/81
385823CTD or STD cast1993-05-17 21:29:0057.125 N, 9.5617 WRRS Challenger CH103
388661CTD or STD cast1993-09-08 03:07:0057.1333 N, 9.5617 WRRS Challenger CH105
389443CTD or STD cast1994-05-07 21:43:0057.125 N, 9.5583 WRRS Challenger CH112
390850CTD or STD cast1994-08-17 01:12:0057.1222 N, 9.5548 WRRS Challenger CH114
434756CTD or STD cast1995-04-15 23:36:0057.1175 N, 9.55 WRRS Charles Darwin CD92B
435391CTD or STD cast1995-04-30 05:51:0057.125 N, 9.55 WRRS Charles Darwin CD92B
390468CTD or STD cast1995-07-30 19:15:0057.1252 N, 9.5373 WRRS Challenger CH120
434074CTD or STD cast1996-01-13 01:26:0057.125 N, 9.55 WRRS Challenger CH124
1075165CTD or STD cast2000-02-03 17:50:0057.1195 N, 9.5605 WRRS Discovery D245
845039CTD or STD cast2003-07-23 21:03:0057.12353 N, 9.56473 WFS Poseidon PO300_2