Metadata Report for BODC Series Reference Number 385128


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
NameCategories
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 CH89/92/016
BODC Series Reference 385128
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1992-03-09 15:24
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval 1.0 decibars
 

Spatial Co-ordinates

Latitude 57.78330 N ( 57° 47.0' N )
Longitude 6.31830 W ( 6° 19.1' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 0.99 m
Maximum Sensor Depth 59.44 m
Minimum Sensor Height 12.56 m
Maximum Sensor Height 71.01 m
Sea Floor Depth 72.0 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
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.

Specifications

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

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 89/92 CTD Data Documentation

Introduction

Documentation for the CTD data collected on RRS Challenger 89/92 (February - March 1992) 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

Cruise Name CH89B
Departure Date 1992-03-07
Arrival Date 1992-03-13
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 NameDML Line K
CategoryOffshore route/traverse

DML Line K

Line K is a survey section in The Minch, Scotland, crossing between Loch Seaforth (Isle of Lewis) and Loch Gairloch (Scottish mainland) via Trodday on the northern tip of the Isle of Skye. The line comprises nine fixed CTD stations, which were established as part of routine monitoring work on the Scottish continental shelf by Dunstaffnage Marine Laboratory (DML). Line K was occupied between the late 1970s and the early 1990s.

Nominal station details

DML Line K: The Minch, Scotland (south of Isle of Lewis - Isle of Skye - west coast mainland)

Station Nominal latitude Nominal longitude Approx.
depth (m)
Comment
1K 57° 53.0' N 06° 35.5' W 125 Loch Seaforth (Isle of Lewis)
2K 57° 51.0' N 06° 30.0' W 105  
3K 57° 49.0' N 06° 24.5' W 75  
4K 57° 47.0' N 06° 19.0' W 55  
5K 57° 45.0' N 06° 13.5' W 52 Off Trodday (Isle of Skye)
6K 57° 43.0' N 06° 08.0' W 120  
7K 57° 43.0' N 06° 01.3' W 100  
8K 57° 43.0' N 05° 54.6' W 120  
9K 57° 43.0' N 05° 47.9' W 55 Loch Gairloch (mainland Scotland)

Other Series linked to this Fixed Station for this cruise - 385073 385085 385097 385104 385116 385141 385153 385165

Other Cruises linked to this Fixed Station (with the number of series) - CH1/85 (9) CH10/81 (7) CH10/84 (9) CH11/83 (9) CH14 (9) CH16/79 (9) CH2/84 (9) CH22 (9) CH25 (9) CH30 (9) CH4/85 (9) CH7B/83 (9) CH8/85 (9) CH9 (8) FR18/87 (8) S5/79 (9)

Fixed Station Information

Station NameDML Line K Station 4K
CategoryOffshore location
Latitude57° 47.00' N
Longitude6° 19.00' W
Water depth below MSL55.0 m

DML Station 4K

Station 4K is one of nine fixed CTD stations crossing The Minch between the Isle of Lewis and the west coast of Scotland, via the northern tip of the Isle of Skye. The station was established by scientists at Dunstaffnage Marine Laboratory (DML).

Other Cruises linked to this Fixed Station (with the number of series) - CH1/85 (1) CH10/84 (1) CH11/83 (1) CH14 (1) CH16/79 (1) CH2/84 (1) CH22 (1) CH25 (1) CH30 (1) CH4/85 (1) CH7B/83 (1) CH8/85 (1) CH9 (1) FR18/87 (1) S5/79 (1)

Fixed Station Information

Station NameDML The Minches CTD Sections
CategoryOffshore area
Latitude57° 54.00' N
Longitude6° 11.25' W
Water depth below MSL

DML The Minches CTD Sections

The Minch and Little Minch (collectively, The Minches), between the Outer Hebrides and the Scottish mainland, have been extensively surveyed since the late 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 'The Minches' CTD Stations

BODC image

Map produced using the GEBCO Digital Atlas.

The triangles indicate the nominal positions of individual Line L stations; nominal positions of Line K and N stations are shown by the circles and squares respectively. Measurements made at repeated 'The Minches' CTD stations lie within a box bounded by co-ordinates 57.517° N, 7.075° W at the south west corner and 58.283° N, 5.3° W at the north east corner.

Nominal station details:

DML The Minches Line L: The Minch, Scotland (west coast mainland - north of Isle of Lewis)

DML Line K: The Minch, Scotland (south of Isle of Lewis - Isle of Skye - west coast mainland)

DML Line N: The Little Minch, Scotland (Isle of Skye - North Uist)

Other Series linked to this Fixed Station for this cruise - 385073 385085 385097 385104 385116 385141 385153 385165

Other Cruises linked to this Fixed Station (with the number of series) - CH1/85 (9) CH10/81 (16) CH10/84 (15) CH11/83 (15) CH14 (21) CH16/79 (21) CH2/78 (6) CH2/84 (15) CH22 (21) CH25 (15) CH30 (13) CH4/85 (21) CH71A (6) CH74A_1 (5) CH7B/83 (9) CH8/85 (21) CH9 (14) FR18/87 (20) LF2/89 (6) S5/79 (15)


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