Metadata Report for BODC Series Reference Number 90453

Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
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 C5A76/005
BODC Series Reference 90453

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1976-04-02 02:38
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -

Spatial Co-ordinates

Latitude 57.53330 N ( 57° 32.0' N )
Longitude 12.63330 W ( 12° 38.0' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 2.58 m
Maximum Sensor Depth 1549.38 m
Minimum Sensor Height 90.61 m
Maximum Sensor Height 1637.42 m
Sea Floor Depth 1640.0 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


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

Inspection of the pressure records from this cruise revealed several negative values (by up to 3 dB) at the start of some profiles. Reasonable temperature and salinity values accompanied the negative pressures, which casts some doubt on the accuracy of the pressure calibration. The affected data values have been flagged as suspect.

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 5A/75 STD Data Documentation


Documentation for the STD data collected on RRS Challenger Cruise 5A/76 (April 1976) by the Scottish Marine Biological Association, Oban, Argyll, Scotland, UK, under the direction of D. J. Ellett.


Inspection of the pressure records from this cruise reveals several negative values (by up to 3db) at the start of some records, (while the temperature and salinity values appear reasonable), thus casting some doubt on the accuracy of the pressure calibration. These data values have been flagged.


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.


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.


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.


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.


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
Temperature (°C) 0.9995 0.0518 0.009
Salinity (ppt) 0.9822 0.5749 0.000
Pressure (dbar) 0.5063 -8.2021 2.418
Delta-S -0.0045 7.7575 5.396

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.


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 Name CH5A/76
Departure Date 1976-03-29
Arrival Date 1976-04-05
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 NameEllett Line/Extended Ellett Line Station E
CategoryOffshore location
Latitude57° 31.98' N
Longitude12° 37.98' W
Water depth below MSL1658.0 m

Ellett Line/Extended Ellett Line: Station E

Station E is one of the fixed CTD stations, which together form The Extended Ellett Line. The line lies between Iceland and the Sound of Mull (Scotland) crossing the Iceland Basin and Rockall Trough via the outcrop of Rockall. As part of this initiative, CTD dips, together with associated discrete sampling of the water column, have typically been carried out annually at this station since September 1996.

Prior to September 1996, Station E was part of a shorter repeated survey section, consisting of 35 fixed stations, known as The Ellett Line (originally termed the Anton Dohrn Seamount Section). This line incorporated those stations across the Rockall Trough and Scottish shelf between Rockall and the Sound of Mull and was visited at regular intervals (usually at least once a year) between 1975 and January 1996.

Other Cruises linked to this Fixed Station (with the number of series) - 0508S (2) 0700S (2) 0703S (1) CD176 (1) CD44 (1) CD92B (1) CH10/84 (1) CH103 (1) CH105 (1) CH10A/75 (1) CH11/77 (1) CH11/83 (1) CH112 (1) CH114 (1) CH11B/78 (1) CH120 (1) CH124 (1) CH13/77 (1) CH14 (1) CH14A/75 (1) CH15/81 (1) CH2/78 (1) CH2/84 (1) CH4/77 (1) CH4/80 (1) CH4/85 (1) CH6/78 (1) CH67A (1) CH6B/81 (1) CH7/80 (1) CH71A (3) CH75B (1) CH7B/82 (1) CH8/76 (1) CH8/85 (1) CH81 (1) CH9/78 (1) CH97 (1) D180 (1) D223A (1) D233 (2) D242 (2) D253 (1) D312 (1) D321B (1) D340A (1) D351 (1) D365 (1) D379 (1) DY031 (2) DY052 (2) JC086 (1) JR20140531 (JR302) (1) LF1/89 (1) LF2/89 (1) PO300_2 (1) PO314 (1)

Fixed Station Information

Station NameEllett Line
CategoryOffshore route/traverse

Ellett Line

The Ellett Line is a hydrographic transect consisting of 35 individual fixed stations which were occupied, usually at least once a year, between 1975 and 1996. The time series is named after the scientist David Ellett, who coordinated the survey work at Dunstaffnage Marine Laboratory (DML), near Oban. The transect ran between the north west coast of Scotland to the small outcrop of Rockall, via the Anton Dohrn Seamount - a prominent bathymetric feature in the Rockall Trough (see map). STD/CTD dips and associated water sampling for the analysis of nutrients were routinely performed during each station occupation.

In 1996 the transect was lengthened to incorporate new additional fixed stations crossing the Iceland Basin from Rockall to Iceland. This transect, which is still routinely occupied annually, is now known as the Extended Ellett Line and is a collaborative effort between scientists at Dunstaffnage Marine Laboratory and the Southampton site of the National Oceanography Centre (NOC).

Map of standard stations (1975-1996)

BODC image

Map produced using the GEBCO Digital Atlas

The white triangles indicate the nominal positions of the Ellett Line stations (1975- 1996). Measurements made along the Ellett Line lie within a box bounded by co-ordinates 56° 40.02' N, 13° 42.0' W at the south west corner and 57° 37.2' N, 6° 7.98' W at the north east corner.

Nominal Ellett Line stations (1975-1996)

Listed below are nominal details of the standard hydrographic stations that formed the Ellett Line between 1975 and January 1996.

Station Latitude Longitude Depth Range
A 57.583 N 13.633 W 130 m 10.0 nm
B 57.567 N 13.333 W 210 m 9.7 nm
C 57.550 N 13.000 W 330 m 10.8 nm
D 57.542 N 12.867 W 1000 m 4.3 nm
E 57.533 N 12.633 W 1658 m 7.6 nm
F 57.508 N 12.250 W 1817 m 12.5 nm
G 57.492 N 11.850 W 1812 m 13.0 nm
H 57.483 N 11.533 W 2020 m 10.3 nm
I 57.467 N 11.317 W 750 m 7.0 nm
J 57.450 N 11.083 W 550 m 7.6 nm
K 57.400 N 10.867 W 850 m 7.6 nm
L 57.367 N 10.667 W 2076 m 6.8 nm
M 57.300 N 10.383 W 2340 m 10.1 nm
N 57.233 N 10.050 W 2100 m 11.5 nm
O 57.150 N 9.700 W 1900 m 12.4 nm
P 57.100 N 9.417 W 1050 m 9.7 nm
Q 57.050 N 9.217 W 350 m 7.2 nm
R 57.000 N 9.000 W 135 m 7.7 nm
S 56.950 N 8.783 W 125 m 7.7 nm
15G 56.883 N 8.500 W 125 m 10.1 nm
T 56.837 N 8.333 W 120 m 6.1 nm
14G 56.808 N 8.167 W 115 m 5.7 nm
13G 56.783 N 8.000 W 110 m 5.7 nm
12G 56.758 N 7.833 W 80 m 5.7 nm
11G 56.733 N 7.667 W 55 m 5.7 nm
10G 56.733 N 7.500 W 220 m 5.5 nm
9G 56.733 N 7.333 W 160 m 5.5 nm
8G 56.733 N 7.167 W 175 m 5.5 nm
7G 56.733 N 7.000 W 145 m 5.5 nm
6G 56.733 N 6.750 W 35 m 8.2 nm
5G 56.733 N 6.600 W 75 m 4.9 nm
4G 56.733 N 6.450 W 115 m 4.9 nm
3G 56.708 N 6.367 W 75 m 3.1 nm
2G 56.683 N 6.283 W 40 m 3.2 nm
1G 56.667 N 6.133 W 190 m 5.0 nm

History of Ellett Line occupations (1975-January 1996)

BODC Cruise Identifier Cruise Dates Ship
CH3/75 4-13 March 1975 RRS Challenger
CH7A/75 1-6 May 1975 RRS Challenger
CH10A/75 4-10 July 1975 RRS Challenger
CH12A/75 26 August-2 September 1975 RRS Challenger
CH14A/75 7-12 November 1975 RRS Challenger
CH5A/76 29 March-5 April 1976 RRS Challenger
CH8/76 19 May-1 June 1976 RRS Challenger
CH12/76 4-15 August 1976 RRS Challenger
CH15/76 7-16 October 1976 RRS Challenger
CH17/76 7-20 December 1976 RRS Challenger
CH4/77 25 February-11 March 1977 RRS Challenger
CH6B/77 14-19 April 1977 RRS Challenger
CH10/77 29 June-10 July 1977 RRS Challenger
CH11/77 12-26 July 1977 RRS Challenger
CH13/77 20 August-3 September 1977 RRS Challenger
CH2/78 30 January-13 February 1978 RRS Challenger
CH6/78 11-21 April 1978 RRS Challenger
CH9/78 31 May-10 June 1978 RRS Challenger
CH11B/78 29 July-12 August 1978 RRS Challenger
CH11D/78 3-17 September 1978 RRS Challenger
CH14B/78 4-11 November 1978 RRS Challenger
CH7/79 10-23 May 1979 RRS Challenger
S5/79 19 June-2 July 1979 RRS Shackleton
CH13/79 11-16 September 1979 RRS Challenger
CH16/79 28 October-11 November 1979 RRS Challenger
CH4/80 26 February-7 March 1980 RRS Challenger
CH7/80 21 April-6 May 1980 RRS Challenger
CH2/81 26 January-4 February 1981 RRS Challenger
CH6A/81 CH6B/81 6-25 April 1981 RRS Challenger
CH10/81 4-14 July 1981 RRS Challenger
CH15/81 6-20 October 1981 RRS Challenger
CH7A/82 CH7B/82 26 April-16 May 1982 RRS Challenger
CH15/82 16-30 October 1982 RRS Challenger
CH7B/83 23 May-2 June 1983 RRS Challenger
CH11/83 10-24 August 1983 RRS Challenger
CH2/84 23 June-8 July 1984 RRS Challenger
CH10/84 16 November-6 December 1984 RRS Challenger
CH1/85 20 January-5 February 1985 RRS Challenger
CH4/85 2-16 May 1985 RRS Challenger
CH8/85 14-28 August 1985 RRS Challenger
CH9 8-22 January 1987 RRS Challenger
CH14 24 April-7 May 1987 RRS Challenger
CH22 23 November-5 December 1987 RRS Challenger
CH25 24 February-7 March 1988 RRS Challenger
CH30 6-23 June 1988 RRS Challenger
D180 20 January-4 February 1989 RRS Discovery
LF1/89 5-11 May 1989 RV Lough Foyle
LF2/89 4-10 August 1989 RV Lough Foyle
CD44 24 November-2 December 1989 RRS Charles Darwin
CH67A 21-29 June 1990 RRS Challenger
CH71A 29 August-5 September 1990 RRS Challenger
CH75B 23 February-3 March 1991 RRS Challenger
CH81 1-8 July 1991 RRS Challenger
CH97 25 September-6 October 1992 RRS Challenger
CH101B 13-20 March 1993 RRS Challenger
CH103 12-24 May 1993 RRS Challenger
CH105 3-16 September 1993 RRS Challenger
CH110 10-20 March 1994 RRS Challenger
CH112 28 April-13 May 1994 RRS Challenger
CH114 15-29 August 1994 RRS Challenger
CH116 17-29 November 1994 RRS Challenger
CD92B 13 April-2 May 1995 RRS Charles Darwin
CH120 18 July-6 August 1995 RRS Challenger
CH124 8-27 January 1996 RRS Challenger

Other Series linked to this Fixed Station for this cruise - 90404 90416 90428 90465 90477 90490 90508 90521 90533 90545 90557 90569 90570 90594 90601 90613 90625

Other Cruises linked to this Fixed Station (with the number of series) - 0508S (58) 0700S (30) 0703S (20) CD176 (32) CD44 (34) CD92B (47) CH1/85 (19) CH10/77 (3) CH10/81 (21) CH10/84 (22) CH101B (13) CH103 (37) CH105 (34) CH10A/75 (15) CH11/77 (28) CH11/83 (35) CH110 (19) CH112 (35) CH114 (31) CH116 (25) CH11B/78 (26) CH11D/78 (14) CH120 (28) CH124 (46) CH12A/75 (3) CH13/77 (19) CH13/79 (17) CH14 (29) CH14A/75 (21) CH14B/78 (17) CH15/80 (8) CH15/81 (16) CH16/79 (13) CH2/78 (32) CH2/81 (13) CH2/82 (4) CH2/84 (29) CH22 (14) CH25 (18) CH3/83 (1) CH30 (23) CH4/77 (19) CH4/80 (29) CH4/85 (30) CH6/78 (25) CH63_2 (5) CH67A (27) CH6A/81 (14) CH6B/77 (24) CH6B/81 (20) CH7/79 (18) CH7/80 (16) CH71A (32) CH74A_1 (13) CH75B (31) CH7A/75 (24) CH7A/82 (24) CH7B/82 (13) CH7B/83 (29) CH8/76 (27) CH8/85 (30) CH81 (30) CH86B (8) CH89B (9) CH9 (25) CH9/78 (22) CH97 (30) CH9B/80 (10) D180 (30) D223A (22) D230 (21) D233 (20) D242 (45) D245 (25) D253 (22) D312 (34) D321B (28) D340A (34) D351 (34) D365 (55) D379 (36) DSK1/86 (10) DY052 (74) FR13/85 (12) FR13/87 (2) FR14B/87 (2) FR18/87 (11) FR7B/86 (6) FR8/86 (13) JC086 (35) JR20140531 (JR302) (37) LF1/89 (29) LF2/89 (30) PO300_2 (31) PO314 (30) S5/79 (8)

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