Metadata Report for BODC Series Reference Number 938695
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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.
|Housing||Plastic or titanium|
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.
JR210 CTD Instrument Description
CTD unit and auxiliary sensors
The CTD system used on cruise JR210 was the Sea-Bird 911 plus. This was mounted on a stainless steel rosette frame, equipped with 24 10-litre Niskin bottles. The CTD was fitted with the following scientific sensors:
|Sensor||Serial Number||Last calibration date|
|Primary Temperature SBE-3P||4302||18 July 2007|
|Secondary Temperature SBE-3P||4235||20 July 2007|
|Primary Conductivity SBE-4C||2875||18 July 2007|
|Secondary Conductivity SBE-4C||2813||17 July 2007|
|Pressure-Digiquartz with TC||0541-75429||18 July 2007|
|Sea-Bird SBE 43 oxygen sensor||0676||3 June 2006|
|Chelsea/Seatech/Wetlab CStar transmissometer||CST-527DR||14 August 2007|
|Chelsea Aquatracka Mk III (chlorophyll a) fluorometer||088-249||13 September 2007|
|Biospherical / Licor PAR / irradiance sensor||7235||26 July 2007|
|SBE35 Thermometer||0047||17 October 2007|
The salinity samples from the CTD were analysed during the cruise in a constant temperature laboratory using the Guildline Autosal 8400 salinometer.
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.
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.
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.
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.
Biospherical Instruments Log Quantum Cosine Irradiance Sensor QCD-905L
The QCD-905L is a submersible radiometer designed to measure irradiance over Photosynthetically Active Radiation (PAR) wavelengths (400-700 nm). It features a cosine directional response when fully immersed in water.
The sensor is a blue-enhanced high stability silicon photovoltaic detector with dielectric and absorbing glass filter assembly, and produces a logarithmic output. Normal output range is -1 to 6 volts with 1 volt per decade. Typically, the instrument outputs 5 volts for full sunlight and has a minimum output of 0.001% full sunlight, where typical noon solar irradiance is 1.5 to 2 x 1017 quanta cm-2 s-1. The instrument can be calibrated with constants for µE cm-2 s-1 or quanta cm-2 s-1.
The QCD-905L can be coupled to a fixed range data acquisition system like a CTD (Conductivity-Temperature-Depth) profiler or current meter. It has an aluminium and PET housing, and a depth rating of 7000 m.
|Wavelength||400 to 700 nm|
|Output range||-1 to 6 V, with 1 V decade-1|
|Operating temperature||-2 to 35°C|
|Depth range||0 - 7000 m|
Further details can be found in the manufacturer's manual.
WETLabs C-Star transmissometer
This instrument is designed to measure beam transmittance by submersion or with an optional flow tube for pumped applications. It can be used in profiles, moorings or as part of an underway system.
Two models are available, a 25 cm pathlength, which can be built in aluminum or co-polymer, and a 10 cm pathlength with a plastic housing. Both have an analog output, but a digital model is also available.
This instrument has been updated to provide a high resolution RS232 data output, while maintaining the same design and characteristics.
|Pathlength||10 or 25 cm|
|Wavelength||370, 470, 530 or 660 nm|
~ 20 nm for wavelengths of 470, 530 and 660 nm
~ 10 to 12 nm for a wavelength of 370 nm
|Temperature error||0.02 % full scale °C-1|
|Temperature range||0 to 30°C|
|Rated depth|| |
600 m (plastic housing)
6000 m (aluminum housing)
JR210 CTD BODC Processing
Data arrived at BODC in a total of 50 ASCII, WHP (WOCE Hydrographic Program) standard files representing the CTD casts deployed during cruise JR210. 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||CPHLPR01||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.
JR210 CTD Originator's Processing
A total of 50 CTD casts were performed during the cruise which sailed from Portland in Dorset along the English Channel and into the North Sea passing the Norweigan coast, up into the Arctic Circle and onto the island group of Svalbard. The CTD was equipped with dual temperature and conductivity sensors, an SBE43 dissolved oxygen sensor, fluorometer, transmissometer and PAR sensor in addition to an independent SBE35 thermometer, all located within and near the bottom of the rosette frame which held 24 10-litre Niskin water sampling bottles. The CTD was usually deployed on the winch on the starboard side of the ship except on a few occassions when the stern gantry was used as icy conditions did not allow for working on the side of the ship. Bottles were fired during the ascent with descent and ascent speeds reaching a maximum of 1 ms-1 during long stretches below the upper 100 m of the water column.
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 7.15 software was used to perform all processing steps.
Raw data files were converted to engineering units and binary .CNV files using the DATCNV program. 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 ensuring the calculations of dissolved oxygen concentration are made using measurements from the same parcel of water. 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 to smooth the rapidly changing data. Twin salinities, density and depth were calculated using the DERIVE program and TRANSLATE wrote the data to an ASCII output .CNV file. Finally, the module BOTTLESUM created the ASCII bottle files (.BTL) for each bottle fired during a cast, with information on pressure and other readings logged at the time of bottle firing.
Despiking of the pressure, oxygen, temperature and salinity data was carried out manually by visualising the data in MATLAB. If a spike occured in pressure, temperature or salinity the whole corresponding scan has been deleted. If the spike occurs in the other channels, the value was set to NaN and all remaining channels were left unedited. Following despiking of the data in MATLAB the module BINAVERAGE averaged the 24 Hz data into 2db-bins, using the downcast data only.
For the CTD casts the following calibrations were applied;
- Sal1calibrated = 0.9691 Sal1uncalibrated + 1.08
- Sal2calibrated = 0.9674 Sal2uncalibrated + 1.1448
- Oxcalibrated = 0.7373 Oxuncalibrated + 0.5593 (units: mgl-1)
Leakey, R. J. G. 2008. ICE CHASE (Changing Sea-ice and Ecosystem Response) RRS JAMES Clark Ross (JR210), Oceans 2025 Arctic Cruise Report.
Oceans 2025 Theme 1, Work Package 1.6: The Effect of Climate Change on the Arctic marine system
This Work Package is run by the Scottish Association for Marine Science (SAMS). Observational and experimental studies will be undertaken in ice-covered and open waters of the western Barents Sea and the northern Svalbard region for which understanding of the physical oceanography is relatively well advanced, and where seasonal access via a UK ice-strength research vessel (RRS James Clark Ross) and installation of year-round in situ instrumentation are feasible.
These studies will complement previous observational and experimental studies undertaken in the western/central Barents Sea (Wassmann, 2002) and will be used, along with published data sets and remotely-sensed data, to parameterise and test a coupled physical-biological model, which will be developed in collaboration with the Proudman Oceanographic Laboratory (POL), in the UK. This model will allow comparison with similar modelling studies undertaken in Arctic waters, including the western/central Barents Sea (Wassman et al., 2006); it will also advance the current state of the art by improved parameterisation of microbial rate processes, and by the incorporation of benthic and sea-ice biogeochemical processes and feedbacks.
This approach, encompassing ship, instrument and modelling platforms, will provide the UK with an enhanced strategic capability to undertake, and be informed by, research on the consequences of rapid climate change in the Arctic.
More detailed information on this Work Package is available at pages 17 - 19 of the official Oceans 2025 Theme 1 document: Oceans 2025 Theme 1
Wassmann P., 2002. Seasonal C-cycling variability in the open ocean and ice-covered waters of the Barents Sea: an introduction, J Mar Syst, 38, 1-7
Wassmann P., Slagstad D., Wexels Riser C., and Reigstad M., 2006. Modelling the ecosystem dynamics of the Barents Sea including the marginal ice zone, II Carbon flux and interannual variability, J Mar Syst, 59, 1-24
|Cruise Name||JR20080723 (JR210)|
|Principal Scientist(s)||Ray Leakey (Scottish Association for Marine Science)|
|Ship||RRS James Clark Ross|
Complete Cruise Metadata Report is available here
No Fixed Station Information held for the Series
The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:
|<||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.)|
|E||End of CTD Down/Up Cast|
|G||Non-taxonomic biological characteristic uncertainty|
|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|
|O||Improbable value - user quality control|
|0||no quality control|
|2||probably good value|
|3||probably bad value|
|6||value below detection|
|7||value in excess|
|A||value phenomenon uncertain|
|Q||value below limit of quantification|