Metadata Report for BODC Series Reference Number 847280

Metadata Summary

Data Description
Data Category CTD or STD cast
Instrument Type
NameCategories
Sea-Bird SBE 43 Dissolved Oxygen Sensor  dissolved gas sensors
Chelsea Technologies Group Aquatracka fluorometer  fluorometers
Sea-Bird SBE 911plus CTD  CTD; water temperature sensor; salinity sensor
Chelsea Technologies Group Alphatracka transmissometer  transmissometers
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Prof Toby Sherwin
Originating Organization Scottish Association for Marine Science
Processing Status banked
Project(s) Oceans 2025
Oceans 2025 Theme 10
Oceans 2025 Theme 10 SO4
 

Data Identifiers

Originator's Identifier CTD005
BODC Series Reference 847280
 

Time Co-ordinates(UT)
Start Time (yyyy-mm-dd hh:mm) 2007-08-26 08:23
End Time (yyyy-mm-dd hh:mm) 2007-08-26 09:59
Nominal Cycle Interval 2.0 decibars
 

Spatial Co-ordinates

Latitude 62.66800 N ( 62° 40.1' N )
Longitude 19.66433 W ( 19° 39.9' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 3.96 m
Maximum Sensor Depth 1668.9 m
Minimum Sensor Height 12.1 m
Maximum Sensor Height 1677.04 m
Sea Floor Depth 1681.0 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 Title
ACYCAA01 1 Dimensionless Sequence number
CPHLPM01 1 Milligrams per cubic metre Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate phase] by in-situ chlorophyll fluorometer and manufacturer's calibration applied
DOXYSC01 1 Micromoles per litre Concentration of oxygen {O2} per unit volume of the water body [dissolved phase] by Sea-Bird SBE 43 sensor and calibration against sample data
POPTDR01 1 Percent Transmittance (red light wavelength) per 25cm of the water body by 25cm path length red light transmissometer
PRESPR01 1 Decibars Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level
PSALCC01 1 Dimensionless Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm and calibration against independent measurements
TEMPCU01 1 Degrees Celsius Temperature of the water body by CTD and NO verification against independent measurements
 

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

Severe contamination of the CTD data has been identified by the data originator due to a surging problem affecting the temperature, salinity and oxygen (and possibly other) channels on all casts from the cruise D321B. A number of regular blips were identified in the profiles and have been attributed to the roll of the ship in the swell due to the winch system adopted on board not compensating for ship heave. These parts of the dataset have not been removed during data processing and have not been flagged as it is difficult to establish which data are erroneous but users should be aware that this problem exists.

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 Dissolved Oxygen Sensor SBE 43 and SBE 43F

The SBE 43 is a dissolved oxygen sensor designed for marine applications. It incorporates a high-performance Clark polarographic membrane with a pump that continuously plumbs water through it, preventing algal growth and the development of anoxic conditions when the sensor is taking measurements.

Two configurations are available: SBE 43 produces a voltage output and can be incorporated with any Sea-Bird CTD that accepts input from a 0-5 volt auxiliary sensor, while the SBE 43F produces a frequency output and can be integrated with an SBE 52-MP (Moored Profiler CTD) or used for OEM applications. The specifications below are common to both.

Specifications

Housing Plastic or titanium
Membrane

0.5 mil- fast response, typical for profile applications

1 mil- slower response, typical for moored applications
Depth rating

600 m (plastic) or 7000 m (titanium)

10500 m titanium housing available on request
Measurement range 120% of surface saturation
Initial accuracy 2% of saturation
Typical stability 0.5% per 1000 h

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

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.

Aquatracka fluorometer

The Chelsea Instruments Aquatracka is a logarithmic response fluorometer. It uses a pulsed (5.5 Hz) xenon light source discharging between 320 and 800 nm through a blue filter with a peak transmission of 420 nm and a bandwidth at half maximum of 100 nm. A red filter with sharp cut off, 10% transmission at 664 nm and 678 nm, is used to pass chlorophyll-a fluorescence to the sample photodiode.

The instrument may be deployed either in a through-flow tank, on a CTD frame or moored with a data logging package.

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

Chelsea Technologies Group ALPHAtracka and ALPHAtracka II transmissometers

The Chelsea Technologies Group ALPHAtracka (the Mark I) and its successor, the ALPHAtracka II (the Mark II), are both accurate (< 0.3 % fullscale) transmissometers that measure the beam attenuation coefficient at 660 nm. Green (565 nm), yellow (590 nm) and blue (470 nm) wavelength variants are available on special order.

The instrument consists of a Transmitter/Reference Assembly and a Detector Assembly aligned and spaced apart by an open support frame. The housing and frame are both manufactured in titanium and are pressure rated to 6000 m depth.

The Transmitter/Reference housing is sealed by an end cap. Inside the housing an LED light source emits a collimated beam through a sealed window. The Detector housing is also sealed by an end cap. A signal photodiode is placed behind a sealed window to receive the collimated beam from the Transmitter.

The primary difference between the ALPHAtracka and ALPHAtracka II is that the Alphatracka II is implemented with surface-mount technology; this has enabled a much smaller diameter pressure housing to be used while retaining exactly the same optical train as in the Mark I. Data from the Mark II version are thus fully compatible with that already obtained with the Mark I. The performance of the Mark II is further enhanced by two electronic developments from Chelsea Technologies Group - firstly, all items are locked in a signal nulling loop of near infinite gain and, secondly, the signal output linearity is inherently defined by digital circuitry only.

Among other advantages noted above, these features ensure that the optical intensity of the Mark II, indicated by the output voltage, is accurately represented by a straight line interpolation between a reading near full-scale under known conditions and a zero reading when blanked off.

For optimum measurements in a wide range of environmental conditions, the Mark I and Mark II are available in 5 cm, 10 cm and 25 cm path length versions. Output is default factory set to 2.5 volts but can be adjusted to 5 volts on request.

Further details about the Mark II instrument are available from the Chelsea Technologies Group ALPHAtrackaII specification sheet.

D321B CTD Instrumentation

CTD unit and auxiliary sensors (stainless steel frame)

The primary CTD system used on cruise D340A was the Sea-Bird 911 plus. This was mounted on a stainless steel rosette frame, equipped with 24 20-litre Niskin bottles until CTD020, after which 10-litre bottles were used until the end of the cruise. The CTD was fitted with the following scientific sensors:

Sensor Serial Number Last calibration date
Primary Temperature SBE-3P 4105 19 March 2009
Secondary Temperature SBE-3P 4116 31 March 2009
Primary Conductivity SBE-4C 3052 13 March 2009
Secondary Conductivity SBE-4C 2580 13 March 2009
Pressure-Digiquartz 90573 20 October 2008
Sea-Bird SBE 43 oxygen sensor 0709 28 May 2008
Chelsea Alphatracka Mk II transmissometer 161048 28 May 2009
Chelsea Aquatracka Mk III (chlorophyll a) fluorometer 088195 27 May 2008
Benthos PSA-916TD altimeter - -
Primary PAR 5 14 April 2008
Secondary Par 5 14 April 2008

The salinity samples from the CTD were analysed during the cruise in a constant temperature laboratory using the Guildline Autosal model 8400B. Dissolved oxygen concentrations were determined using a Winkler titration technique

D321B CTD Originator Processing (Stainless Steel)

Sampling Strategy

A total of 61 CTD casts were performed during the cruise which sailed between Reykjavík in Iceland and Fairlie on the Clyde in Scotland, incorporating the Extended Ellett Line and Wyville Thomson Ridge. 54 of the casts deployed during the cruise were housed in a stainless steel frame equipped with dual temperature and conductivity sensors. The CTDs were located within and near the bottom of the rosette frame which held 24 20-litre Niskin water sampling bottles. The CTD was deployed from amidship on the starboard side using a winch without a functioning heave compensation system. Bottles were fired during the ascent with descent and ascent speeds reaching a maximum of 60 m / minute during long stretches below the upper 100 m of the water column.

Data Processing

Following the completion of each CTD cast the data were saved to the deck unit PC and transferred over the network to a Unix data disk. SBE Seasave Win32 V 5.35 software was used to perform all processing steps.

Raw data files were converted to engineering units and ASCII (.CNV) files using the DATCNV program. SeaBird bottle data files (.BTL), with information on pressure and other readings logged at the time of bottle firing, were also generated during the data conversion process. The WILDEDIT program was run to remove any large pressure spikes and then the SeaSoft program ALIGNCTD was run to advance the oxygen measurements by 4 seconds (within the typical range given by the SeaBird manual). CELLTM was run, according to Sea-Bird's recommendations, to remove conductivity cell thermal mass effects from the measured conductivity and FILTER was run on the pressure channel using a low-pass filter value of 0.2 which, following tests was deemed to give the best results for D321B data. Finally salinity and density were calculated using the DERIVE program and TRANSLATE wrote the data to an output.CNV file. Despiking was carried out by visualising the data in MATLAB. If a spike occured in pressure, temperature or salinity the whole corresponding scan is deleted. If the spike occurs in the other channels, the value is set to NaN and all remaining channels are left unedited. Following despiking of the data in MATLAB the program LOOPEDIT was run with a minimum CTD velocity of 0.25 m/s. Finally the data were binned to 2 db intervals using the BINAVERAGE program thus being formatted according to the WHP (WOCE Hydrographic Programme) standards.

Comparison between primary and secondary temperature and conductivity sensors on the stainless steel casts suggested primary sensors functioned well for the duration of the cruise so for all casts the primary temperature and conductivity sensors were used during the processing steps outlined above.

Calibrations

For the stainless steel CTD casts the salinity and oxygen data were later calibrated using the following equations:

The oxygen data were converted from mg/l to µmol/kg using the following equation:

References

Sherwin, T. A. et al, (2007). 'Cruise D321B Reykjavic to Clyde via Rockall, Scotland and the Wyville Thomson Ridge', Internal Report No 255, Scottish Association for Marine Science.

Available - Cruise D321B Internal Report

Dumont, E. and Sherwin, T. (2008). 'SAMS CTD data processing protocol Issue 1', Internal Report No 257, Scottish Association for Marine Science.

Available - SAMS CTD data processing protocol

D321B CTD Processing undertaken by BODC

Data arrived at BODC in a total of 61 ASCII, WHP (WOCE Hydrographic Program) standard files with 54 of these files representing the CTD casts from the titanium frame deployed during cruise D321B. These files contain 2db-bin averaged data including temperature, salinity and dissolved oxygen channels processed to WOCE standards alongside concurrent fluorometer and transmissometer data.

Additional 24 Hz ASCII files containing data sampled at their original density were also supplied to BODC. These files contain some additional parameters compared to the 2db-bin averaged data files but due to having fewer quality control procedures applied these data have not undergone any further BODC processing. They have however been archived at BODC in their original format and are available upon request.

The lodged WHPO standard casts were reformatted to BODC's internal QXF format. The following table shows the mapping of variables within the ASCII files to appropriate BODC parameter codes:

Originator' Variable Units Description BODC Parameter Code Units Comments
Pressure dbar Pressure exerted by the water column PRESPR01 dbar Manufacturer's calibration applied
Temperature °C Temperature of the water column by CTD TEMPCU01 °C -
Salinity - Practical salinity of the water column PSALCC01 - Calibrated by data originator using discrete water samples from CTD bottles
Dissolved Oxygen Concentration umol/l Concentration of oxygen per unit volume of the water column DOXYSC01 umol/l Calibrated by data originator using discrete water samples from CTD bottles
Transmittance % Transmittance per unspecified length of the water column by transmissometer POPTDR01 % -
Fluorescence mg/m3 Concentration of chlorophyll-a per unit volume of the water column CPHLPM01 mg/m3 -

The reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag, and missing data marked by both setting the data to an appropriate value and setting the quality control flag.

Project Information

Oceans 2025 - The NERC Marine Centres' Strategic Research Programme 2007-2012

Who funds the programme?

The Natural Environment Research Council (NERC) funds the Oceans 2025 programme, which was originally planned in the context of NERC's 2002-2007 strategy and later realigned to NERC's subsequent strategy (Next Generation Science for Planet Earth; NERC 2007).

Who is involved in the programme?

The Oceans 2025 programme was designed by and is to be implemented through seven leading UK marine centres. The marine centres work together in coordination and are also supported by cooperation and input from government bodies, universities and other partners. The seven marine centres are:

Oceans2025 provides funding to three national marine facilities, which provide services to the wider UK marine community, in addition to the Oceans 2025 community. These facilities are:

The NERC-run Strategic Ocean Funding Initiative (SOFI) provides additional support to the programme by funding additional research projects and studentships that closely complement the Oceans 2025 programme, primarily through universities.

What is the programme about?

Oceans 2025 sets out to address some key challenges that face the UK as a result of a changing marine environment. The research funded through the programme sets out to increase understanding of the size, nature and impacts of these changes, with the aim to:

In order to address these aims there are nine science themes supported by the Oceans 2025 programme:

In the original programme proposal there was a theme on health and human impacts (Theme 7). The elements of this Theme have subsequently been included in Themes 3 and 9.

When is the programme active?

The programme started in April 2007 with funding for 5 years.

Brief summary of the programme fieldwork/data

Programme fieldwork and data collection are to be achieved through:

The data is to be fed into models for validation and future projections. Greater detail can be found in the Theme documents.

Oceans 2025 Theme 10

Oceans 2025 is a strategic marine science programme, bringing marine researchers together to increase people's knowledge of the marine environment so that they are better able to protect it for future generations.

Theme 10: Integration of Sustained Observations in the Marine Environment spans all marine domains from the sea-shore to the global ocean, providing data and knowledge on a wide range of ecosystem properties and processes (from ocean circulation to biodiversity) that are critical to understanding Earth system behaviour and identifying change. They have been developed not merely to provide long-term data sets, but to capture extreme or episodic events, and play a key role in the initialisation and validation of models. Many of these SOs will be integrated into the newly developing UK Marine Monitoring Strategy - evolving from the Defra reports Safeguarding our Seas (2002) and Charting Progress (2005), thus contributing to the underpinning knowledge for national marine stewardship. They will also contribute to the UK GOOS Strategic Plan (IACMST, 2006) and the Global Marine Assessment.

Weblink: http://www.oceans2025.org/

Oceans 2025 Theme 10, Sustained Observation Activity 4: The Extended Ellett Line

The Ellett Line (begun in 1975 and since 1996 the Extended Ellett Line from Scotland to Iceland) crosses important north Atlantic Meridional Overturning Circulation (MOC) components and thus provides an additional contribution to understanding the north Atlantic response to climate change. Sustained Observation Activity (SO) 4 will repeat this section annually collecting a wide variety of physical and biogeochemical measurements, and will, to enhance the time variable component, make use of Argo floats and gliders. SO 4 will be implemented by physical, biological and chemical scientists at the National Oceanography Centre, Southampton (NOCS) and the Scottish Association for Marine Science (SAMS).

SO 4 formally contributes to the Department for Environment, Food and Rural Affairs (DEFRA)-funded Marine Environmental Change Network (MECN). Established in 2002 to coordinate and promote the collection and utilisation of marine time-series and long-term data sets, the goal of the network is to use long-term marine environmental data from around the British Isles and Ireland to separate natural fluctuations from global, regional and local anthropogenic impacts.

The specific deliverables for SO 4 are:

More detailed information on this Work Package is available at pages 15 - 16 of the official Oceans 2025 Theme 10 document: Oceans 2025 Theme 10

Weblink: http://www.oceans2025.org/

Data Activity or Cruise Information

Cruise

Cruise Name D321B
Departure Date 2007-08-24
Arrival Date 2007-09-09
Principal Scientist(s)Toby J Sherwin (Scottish Association for Marine Science)
Ship RRS Discovery

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Station NameExtended Ellett Line
CategoryOffshore route/traverse

Extended Ellett Line

The Extended Ellett Line is a hydrographic transect consisting of 58 individual fixed stations which have been occupied, typically on an annual basis, since September 1996. The Line runs from the south of Iceland, across the Iceland Basin to the outcrop of Rockall, and across the Rockall Trough to the north west coast of Scotland (see map). CTD dips and associated water sampling for the analysis of nutrients are routinely performed during each station occupation.

The Extended Ellett Line augments the original Ellett Line time series - a shorter repeated transect which encompassed those stations between Rockall and Scotland. Work on the Ellett Line was typically carried out at least once a year between 1975 and 1996.

Map of standard stations (1996-present)

BODC image

Map produced using the GEBCO Digital Atlas

The white triangles indicate the nominal positions of the Extended Ellett Line stations visited since September 1996. Measurements made along the Extended Ellett Line lie within a box bounded by co-ordinates 56° N, 21° W at the south west corner and 65° N, 6° W at the north east corner.

Nominal Extended Ellett Line stations (September 1996-present)

Listed below are nominal details of the standard hydrographic stations that have formed the Extended Ellett Line since September 1996.

Station Latitude Longitude Depth Range
IB23S 63.318 N 20.210 W 125 m -
IB22S 63.217 N 20.067 W 660 m 0.0 nm
IB21S 63.133 N 19.917 W 1030 m 6.5 nm
IB20S 62.917 N 19.550 W 1415 m 16.4 nm
IB19S 62.667 N 19.667 W 1500 m 16.0 nm
IB18S 62.333 N 19.833 W 1800 m 16.0 nm
IB17 62.000 N 20.000 W 1700 m 20.6 nm
IB16 61.500 N 20.000 W 2000 m 30.1 nm
IB15 61.250 N 20.000 W 2375 m 15.0 nm
IB14 61.000 N 20.000 W 2400 m 15.0 nm
IB13 60.500 N 20.000 W 2500 m 30.1 nm
IB12 60.000 N 20.000 W 2700 m 30.1 nm
IB11 59.667 N 19.117 W 2680 m 33.3 nm
IB10 59.400 N 18.417 W 2420 m 26.7 nm
IB9 59.333 N 18.233 W 1910 m 6.9 nm
IB8 59.200 N 17.883 W 1540 m 13.4 nm
IB7 59.117 N 17.667 W 1000 m 8.3 nm
IB6 58.950 N 17.183 W 850 m 18.0 nm
IB5 58.883 N 17.000 W 1150 m 7.0 nm
IB4 58.500 N 16.000 W 1210 m 38.8 nm
IB3 58.250 N 15.333 W 680 m 25.8 nm
IB2 57.950 N 14.583 W 480 m 29.9 nm
IB1 57.667 N 13.900 W 160 m 27.7 nm
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

Occupations of the Extended Ellett Line (September 1996-present)

BODC Cruise Identifier Cruise Dates Ship
D223A 28 September-21 October 1996 RRS Discovery
D230 7 August-17 September 1997 RRS Discovery
D233 23 April-1 June 1998 RRS Discovery
D242 7 September-6 October 1999 RRS Discovery
D245 * 27 January-20 February 2000 RRS Discovery
0700S * 8-22 May 2000 FRV Scotia
D253 4 May-20 June 2001 RRS Discovery
0703S * 15 April-5 May 2003 FRV Scotia
PO300_2 * 19 July-6 August 2003 RRS Poseidon
PO314 11 July-23 July 2004 RV Poseidon
CD176 6 October-1 November 2005 RRS Charles Darwin
D312 11-31 October 2006 RRS Discovery
D321A 24 July-23 August 2007 RRS Discovery
D321B 24 August-9 September 2007 RRS Discovery
0508S * 6-25 May 2008 FRV Scotia
D340A 10-25 June 2009 RRS Discovery
D351 10-28 May 2010 RRS Discovery
D365 13 May-02 June 2011 RRS Discovery

* These cruises only surveyed the original hydrographic section between Scotland and Rockall.

Other Series linked to this Fixed Station for this cruise - 847243 847255 847267 847279 847292 847311 847335 847347 847359 847360 847372 847384 847396 847403 847415 847427 847439 847440 847452 847464 847476 847488 847507 847519 847520 847532 847544 847556 847568 847612 847624 847636 847648 847661 847845 847857 847869 847870 847882 847894 974580 974592 974611 974623 974635 974647 974659 974660 974672 974684 1015463 1015475 1015487 1015499 1015506 1015518 1015531 1043427

Other Cruises linked to this Fixed Station (with the number of series) - 0508S (29) 0700S (20) 0703S (20) CD176 (40) D233 (25) D242 (45) D245 (25) D312 (51) D321 (D321A) (12) D321B (58) D340A (58) D351 (23) PO300_2 (31)

Fixed Station Information

Station NameExtended Ellett Line Station IB19S
CategoryOffshore location
Latitude62° 40.02' N
Longitude19° 40.02' W
Water depth below MSL1500.0 m

Extended Ellett Line: Fixed Station IB19S

Station IB19S is one of 58 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.

Other Cruises linked to this Fixed Station (with the number of series) - CD176 (1) D233 (1) D242 (1) D312 (1) D340A (1) D351 (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