Metadata Report for BODC Series Reference Number 90348


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
NameCategories
Bissett-Bermann 9006 STD 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
Project(s) -
 

Data Identifiers

Originator's Identifier C1475/024
BODC Series Reference 90348
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1975-11-10 22:38
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 57.81500 N ( 57° 48.9' N )
Longitude 9.34660 W ( 9° 20.8' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 4.06 m
Maximum Sensor Depth 180.24 m
Minimum Sensor Height 1.75 m
Maximum Sensor Height 177.94 m
Sea Floor Depth 182.0 m
Sensor Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor 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 CODE Rank Units Short Title Title
PRESPR01 1 Decibars Pres_Z Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level
SSALPR01 1 Parts per thousand UspSal Salinity of the water body by conductivity cell
TEMPST01 1 Degrees Celsius WC_temp_CTD Temperature 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-Berman 9060 Salinity Temperature and Depth

The B-B 9060 STD measured salinity, temperature and depth and whose analogue output was in graphical form. The plots created were of salinity and temperature versus depth which had to be manually digitised.

RRS Challenger 14/75 STD Data Documentation

Introduction

Documentation for the STD data collected on RRS Challenger Cruise 14/75 (November 1975) by the Scottish Marine Biological Association, Oban, Argyll, Scotland, UK, under the direction of D. J. Ellett.

Instrumentation

The instrument used was a Bissett Berman STD system and the data were logged on a Hewlett Packard 9820. Instrument lowering and raising speeds between 0.5 m/s and 1 m/s. An acoustic pinger was placed above the STD to give an accurate depth measurement, this could then be used to check the STD pressure calibration. An NIO bottle with reversing thermometers was placed above the pinger, within 2m of the STD 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.

Calibration

The STD 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.

Temperature

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

Temperature (°C) = (10 6 /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(STD) + c

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

Salinity

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

Salinity (ppt) = (10 6 /Ps - 4995)/290.6 + 30
where Ps is the salinity period in microseconds.

These values were then plotted against the STD salinity and a regression line fitted to the data such that:

Salinity(WB) = m x Salinity(STD) + c + (m1 x Pressure + c1)/1000

Then the regression coefficients were applied to correct the STD salinity data. The data showed a salinity - pressure dependency, this was corrected by plotting delta-S (i.e. calibrated salinity - calculated salinity) against pressure to determine the slope (m1) and intercept (c1). These were then incorporated into the equation as shown above. The regression coefficients are given in the table below.

Pressure

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 = (10 6 /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(STD) + c

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

Variable Slope (m) Intercept (c) Standard
Deviation
Temperature (°C) 1.0008 0.0302 0.013
Salinity (ppt) 0.9967 0.0750 0.013
Pressure (dbar) 0.5066 -4.3443 3.675
Delta-S 0.0053 -2.5335 12.435

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 salinity. These were then applied to the uncalibrated data 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.

References

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.


Project Information


No Project Information held for the Series

Data Activity or Cruise Information

Cruise

Cruise Name CH14A/75
Departure Date 1975-11-07
Arrival Date 1975-11-12
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 Line BN
CategoryOffshore route/traverse

DML Line BN

Line BN is a survey section heading north west from the Monach Islands (off North Uist, Scotland), to the shelf edge beyond St Kilda. The line comprises nine fixed STD/CTD stations, which were established as part of routine monitoring work on the Scottish continental shelf by Dunstaffnage Marine Laboratory (DML). Line J was occupied between the mid 1970s and the late 1980s.

Nominal station details

DML Line BN: Monach Islands (Scotland) - St Kilda shelf edge (Scotland)

Station Nominal latitude Nominal longitude Approx.
depth (m)
Comment
BN1 57° 28.0' N 07° 40.5' W 38 Monach Islands
BN2 57° 31.5' N 07° 58.0' W 50  
BN3 57° 35.0' N 08° 15.5' W 115  
BN4 57° 38.5' N 08° 33.0' W 145 South of St Kilda
BN5 57° 42.0' N 08° 50.5' W 150 South west of St Kilda
BN6 57° 45.5' N 09° 08.0' W 140  
BN7 57° 48.0' N 09° 21.0' W 220  
BN8 57° 50.5' N 09° 34.0' W 480  
BN9 57° 53.5' N 09° 48.0' W 1150  

Other Series linked to this Fixed Station for this cruise - 90324 90336

Other Cruises linked to this Fixed Station (with the number of series) - CH10/77 (2) CH11/83 (5) CH12A/75 (3) CH14B/80 (8) CH2/78 (9) CH2/84 (8) CH22 (8) CH4/85 (9) CH6/78 (5) CH6B/81 (8) CH7B/83 (7) CH9/78 (7) CH9B/80 (4) S5/79 (3)

Fixed Station Information

Station NameDML Line BN Station BN7
CategoryOffshore location
Latitude57° 48.00' N
Longitude9° 21.00' W
Water depth below MSL220.0 m

DML Station BN7

Station BN7 is one of nine fixed STD/CTD stations crossing the Hebridean Shelf from the Monach Islands (off North Uist, Scotland) to the shelf edge beyond St Kilda. The station was established by scientists at Dunstaffnage Marine Laboratory (DML).

Other Cruises linked to this Fixed Station (with the number of series) - CH11/83 (1) CH12A/75 (1) CH14B/80 (1) CH2/78 (1) CH2/84 (1) CH22 (1) CH4/85 (1) CH6B/81 (1) CH7B/83 (1) CH9/78 (1) CH9B/80 (1)

Fixed Station Information

Station NameDML Outer Hebrides STD/CTD Sections
CategoryOffshore area
Latitude58° 15.25' N
Longitude8° 5.75' W
Water depth below MSL

DML Outer Hebrides STD/CTD Sections

The shelf area to the north and west of the Scottish Outer Hebrides has been extensively surveyed since the mid 1970s by numerous research and government institutes. The region contains several repeated hydrographic stations, which collectively form transects. These repeated survey transects represent the northern part of a greater network of similar sections on the western Scottish continental shelf, which were established by Dunstaffnage Marine Laboratory (DML).

Map of standard Outer Hebrides STD/CTD Stations

BODC image

Map produced using the GEBCO Digital Atlas.

The triangles indicate the nominal positions of individual Line M stations; nominal positions of Line J and BN stations are shown by the circles and squares respectively. Measurements made at repeated Outer Hebrides STD/CTD stations lie within a box bounded by co-ordinates 57.467° N, 9.8° W at the south west corner and 59.042° N, 6.392° W at the north east corner.

Nominal station details:

DML Line M: North Lewis (Scotland) - Hebridean Shelf Edge (Scotland)

DML Line J: Loch Resort, Lewis (Scotland) - Hebridean Shelf Edge (Scotland)

DML Line BN: Monach Islands (Scotland) - St Kilda/Hebridean Shelf Edge (Scotland)

Other Series linked to this Fixed Station for this cruise - 90324 90336

Other Cruises linked to this Fixed Station (with the number of series) - CH10/77 (2) CH10/81 (4) CH11/83 (20) CH12A/75 (3) CH14B/80 (8) CH2/78 (10) CH2/84 (25) CH22 (28) CH25 (5) CH30 (9) CH4/85 (26) CH6/78 (5) CH6B/81 (8) CH7B/83 (15) CH8/85 (18) CH9/78 (7) CH9B/80 (4) FR18/87 (6) S5/79 (4)


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