Metadata Report for BODC Series Reference Number 385546

Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
Sea-Bird SBE 911 CTD  CTD; water temperature sensor; salinity sensor
Sea-Bird SBE 13 Dissolved Oxygen Sensor  dissolved gas sensors
Instrument Mounting research vessel
Originating Country United Kingdom
Originator Dr David Ellett
Originating Organization Dunstaffnage Marine Laboratory (now Scottish Association for Marine Science)
Processing Status banked
Project(s) -

Data Identifiers

Originator's Identifier CH103/93/001
BODC Series Reference 385546

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1993-05-14 19:25
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval 1.0 decibars

Spatial Co-ordinates

Latitude 57.58330 N ( 57° 35.0' N )
Longitude 13.63670 W ( 13° 38.2' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 0.99 m
Maximum Sensor Depth 104.99 m
Minimum Sensor Height 5.01 m
Maximum Sensor Height 109.01 m
Sea Floor Depth 110.0 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
DOXYPR01 1 Micromoles per litre WC_dissO2_Beck Concentration of oxygen {O2 CAS 7782-44-7} per unit volume of the water body [dissolved plus reactive particulate phase] by in-situ Beckmann probe
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
PSALPR01 1 Dimensionless P_sal Practical salinity of the water body by conductivity cell and computation using UNESCO 1983 algorithm
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

The oxygen data collected on this cruise have not been calibrated against sample data and should be used with great caution.

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

Sea Bird Electronics SBE13 Dissolved Oxygen Sensor

The SBE 13 was designed as an auxiliary sensor for Sea Bird SBE 9plus, but can fitted in custom instrumentation applications. When used with the SBE 9 Underwater Unit, a flow-through plenum improves the data quality, as the pumping water over the sensor membrane reduces the errors caused by oxygen depletion during the periods of slow or intermittent flushing and also reduces exposure to biofouling.

The output voltage is proportional to membrane current (oxygen current) and to the sensor element's membrane temperature (oxygen temperature), which is used for internal temperature compensation.

Two versions of the SBE 13 are available: the SBE 13Y uses a YSI polarographic element with replaceable membranes to provide in situ measurements up to 2000 m depth and the SBE 13B uses a Beckman polarographic element to provide in situ measurements up to 10500 m depth, depending on the sensor casing. This sensor includes a replaceable sealed electrolyte membrane cartridge.

The SBE 13 instrument has been out of production since 2001 and has been superseded by the SBE 43.


Measurement range 0 to 15 mL L -1
Accuracy 0.1 mL L -1
Time response

2 s at 25°C

5 s at 0°C

Depth range

2000 m (SBE 13Y- housing in anodized aluminum)

6800 m (SBE 13B- housing in anodized aluminum)

105000 m (SBE 13B- housing in titanium)

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

Sea-Bird Electronics SBE 911 and SBE 917 series CTD profilers

The SBE 911 and SBE 917 series of conductivity-temperature-depth (CTD) units are used to collect hydrographic profiles, including temperature, conductivity and pressure as standard. Each profiler consists of an underwater unit and deck unit or SEARAM. Auxiliary sensors, such as fluorometers, dissolved oxygen sensors and transmissometers, and carousel water samplers are commonly added to the underwater unit.

Underwater unit

The CTD underwater unit (SBE 9 or SBE 9 plus ) comprises a protective cage (usually with a carousel water sampler), including a main pressure housing containing power supplies, acquisition electronics, telemetry circuitry, and a suite of modular sensors. The original SBE 9 incorporated Sea-Bird's standard modular SBE 3 temperature sensor and SBE 4 conductivity sensor, and a Paroscientific Digiquartz pressure sensor. The conductivity cell was connected to a pump-fed plastic tubing circuit that could include auxiliary sensors. Each SBE 9 unit was custom built to individual specification. The SBE 9 was replaced in 1997 by an off-the-shelf version, termed the SBE 9 plus , that incorporated the SBE 3 plus (or SBE 3P) temperature sensor, SBE 4C conductivity sensor and a Paroscientific Digiquartz pressure sensor. Sensors could be connected to a pump-fed plastic tubing circuit or stand-alone.

Temperature, conductivity and pressure sensors

The conductivity, temperature, and pressure sensors supplied with Sea-Bird CTD systems have outputs in the form of variable frequencies, which are measured using high-speed parallel counters. The resulting count totals are converted to numeric representations of the original frequencies, which bear a direct relationship to temperature, conductivity or pressure. Sampling frequencies for these sensors are typically set at 24 Hz.

The temperature sensing element is a glass-coated thermistor bead, pressure-protected inside a stainless steel tube, while the conductivity sensing element is a cylindrical, flow-through, borosilicate glass cell with three internal platinum electrodes. Thermistor resistance or conductivity cell resistance, respectively, is the controlling element in an optimized Wien Bridge oscillator circuit, which produces a frequency output that can be converted to a temperature or conductivity reading. These sensors are available with depth ratings of 6800 m (aluminium housing) or 10500 m (titanium housing). The Paroscientific Digiquartz pressure sensor comprises a quartz crystal resonator that responds to pressure-induced stress, and temperature is measured for thermal compensation of the calculated pressure.

Additional sensors

Optional sensors for dissolved oxygen, pH, light transmission, fluorescence and others do not require the very high levels of resolution needed in the primary CTD channels, nor do these sensors generally offer variable frequency outputs. Accordingly, signals from the auxiliary sensors are acquired using a conventional voltage-input multiplexed A/D converter (optional). Some Sea-Bird CTDs use a strain gauge pressure sensor (Senso-Metrics) in which case their pressure output data is in the same form as that from the auxiliary sensors as described above.

Deck unit or SEARAM

Each underwater unit is connected to a power supply and data logging system: the SBE 11 (or SBE 11 plus ) deck unit allows real-time interfacing between the deck and the underwater unit via a conductive wire, while the submersible SBE 17 (or SBE 17 plus ) SEARAM plugs directly into the underwater unit and data are downloaded on recovery of the CTD. The combination of SBE 9 and SBE 17 or SBE 11 are termed SBE 917 or SBE 911, respectively, while the combinations of SBE 9 plus and SBE 17 plus or SBE 11 plus are termed SBE 917 plus or SBE 911 plus .


Specifications for the SBE 9 plus underwater unit are listed below:

Parameter Range Initial accuracy Resolution at 24 Hz Response time
Temperature -5 to 35°C 0.001°C 0.0002°C 0.065 sec
Conductivity 0 to 7 S m -1 0.0003 S m -1 0.00004 S m -1 0.065 sec (pumped)
Pressure 0 to full scale (1400, 2000, 4200, 6800 or 10500 m) 0.015% of full scale 0.001% of full scale 0.015 sec

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

RRS Challenger Cruise 103 CTD Data Documentation


Documentation for the CTD data collected on RRS Challenger 103 (May 1993) by the Dunstaffnage Marine Laboratory, Oban, Argyll, Scotland, UK, under the direction of D. J. Ellett.

Instrumentation and Processing

The instrument used was a Seabird 9/11 CTD, and the data were processed using the Seabird software. The manufacturer's calibrations were used. Data have been averaged to 1 decibar values.

Project Information

No Project Information held for the Series

Data Activity or Cruise Information


Cruise Name CH103
Departure Date 1993-05-12
Arrival Date 1993-05-24
Principal Scientist(s)David J Ellett (Dunstaffnage Marine Laboratory)
Ship RRS Challenger

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Station NameEllett Line/Extended Ellett Line Station A
CategoryOffshore location
Latitude57° 34.98' N
Longitude13° 37.98' W
Water depth below MSL130.0 m

Ellett Line/Extended Ellett Line: Station A

Station A 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 A 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 (2) CD176 (1) CD44 (1) CD92B (1) CH10/84 (1) CH105 (1) CH10A/75 (1) CH11/77 (1) CH11/83 (1) CH112 (1) CH114 (1) CH11B/78 (1) CH120 (1) CH124 (1) CH14 (1) CH14A/75 (1) CH4/77 (1) CH4/80 (1) CH4/85 (1) CH5A/76 (1) CH67A (1) CH6B/77 (1) CH6B/81 (1) CH75B (1) CH7B/82 (1) CH8/76 (1) CH8/85 (1) CH81 (1) CH97 (1) D223A (1) D230 (1) D233 (2) D242 (2) D253 (1) D321B (1) D340A (1) D351 (1) D365 (1) D379 (1) DY031 (4) DY052 (2) JC086 (1) JR20140531 (JR302) (2) 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 - 385558 385571 385583 385595 385602 385614 385626 385638 385651 385663 385675 385687 385699 385706 385718 385731 385743 385755 385767 385780 385811 385835 385903 385939 385940 385952 385964 385976 385988 386003 386015 386027 386039 386040 386052 386064

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) 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) CH5A/76 (18) 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
Q value below limit of quantification