Metadata Report for BODC Series Reference Number 1792963
Metadata Summary
Problem Reports
Data Access Policy
Narrative Documents
Project Information
Data Activity or Cruise Information
Fixed Station Information
BODC Quality Flags
SeaDataNet Quality Flags
Metadata Summary
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Problem Reports
No Problem Report Found in the Database
Data Access Policy
Open 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.
If the Information Provider does not provide a specific attribution statement, or if you are using Information from several Information Providers and multiple attributions are not practical in your product or application, you may consider using the following:
"Contains public sector information licensed under the Open Government Licence v1.0."
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.
Instrument Description for JR20120207 (JR55B, JR259, JR275)
CTD Unit and Auxiliary Sensors
REVIEW
The CTD unit comprised a Sea-Bird Electronics (SBE) 9 plus underwater unit, an SBE 11 plus deck unit, a 24-way SBE 32 carousel and 24 10 L Water Samplers; all of which were mounted on a titanium 24-way CTD frame. Attached to the CTD were two SBE 3P temperature sensors, two SBE 4C conductivity sensors, one Paroscientific Digiquartz pressure sensor, two SBE 43 dissolved oxygen sensor, one Biosperical PAR sensor, one tritech Altimeter and one Chelsea Aquatracka MKIII fluorometer.
Sensor unit | Model | Serial number | Full specification | Calibration dates (YYYY/MM/DD) | Comments |
---|---|---|---|---|---|
CTD underwater unit | SBE 9 plus | SBE 9 plus | |||
CTD deck unit | SBE 11 plus | SBE 11 plus; | |||
Carousel | SBE 32 | SBE 32 | 24 Position Pylon | ||
Pressure sensor | Paroscientific Digiquartz | 0771 | Paroscientific Digiquartz | 2010/06/25 | |
Temperature sensor | SBE 3P | 4874 | SBE 03P | 2010/06/25 | Primary sensor |
Temperature sensor | SBE 3P | 2191 | SBE 03P | 2010/06/23 | Secondary sensor |
Conductivity sensor | SBE 4C | 3248 | SBE 04C | 2010/06/25 | Primary sensor |
Conductivity sensor | SBE 4C | 1912 | SBE 04C | 2010/06/25 | Secondary sensor |
Dissolved oxygen sensor | SBE 43 | 0245 | SBE 43 | 2008/12/10 | Primary sensor |
Dissolved oxygen sensor | SBE 43 | 0242 | SBE 43 | 2009/01/21 | Secondary sensor |
Altimeter | Tritech | 2130.27001 | Altimeter PA200 | 2006/11/10 | |
Irradiance sensor (DWIRR) | QCD905L | 7235 | Biospherical QCD905L | 2010/07/12 | Measuring downwelling irradiance |
Fluorometer | Chelsea MKIII Aquatracka | 088-249 | Chelsea MKII Aquatracka | 2007/11/13 |
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.
Chelsea Technologies Group Aquatracka MKIII fluorometer
The Chelsea Technologies Group Aquatracka MKIII is a logarithmic response fluorometer. Filters are available to enable the instrument to measure chlorophyll, rhodamine, fluorescein and turbidity.
It uses a pulsed (5.5 Hz) xenon light source discharging along two signal paths to eliminate variations in the flashlamp intensity. The reference path measures the intensity of the light source whilst the signal path measures the intensity of the light emitted from the specimen under test. The reference signal and the emitted light signals are then applied to a ratiometric circuit. In this circuit, the ratio of returned signal to reference signal is computed and scaled logarithmically to achieve a wide dynamic range. The logarithmic conversion accuracy is maintained at better than one percent of the reading over the full output range of the instrument.
Two variants of the instrument are available, both manufactured in titanium, capable of operating in depths from shallow water down to 2000 m and 6000 m respectively. The optical characteristics of the instrument in its different detection modes are visible below:
Excitation | Chlorophyll a | Rhodamine | Fluorescein | Turbidity |
---|---|---|---|---|
Wavelength (nm) | 430 | 500 | 485 | 440* |
Bandwidth (nm) | 105 | 70 | 22 | 80* |
Emission | Chlorophyll a | Rhodamine | Fluorescein | Turbidity |
Wavelength (nm) | 685 | 590 | 530 | 440* |
Bandwidth (nm) | 30 | 45 | 30 | 80* |
* The wavelengths for the turbidity filters are customer selectable but must be in the range 400 to 700 nm. The same wavelength is used in the excitation path and the emission path.
The instrument measures chlorophyll a, rhodamine and fluorescein with a concentration range of 0.01 µg l-1 to 100 µg l-1. The concentration range for turbidity is 0.01 to 100 FTU (other wavelengths are available on request).
The instrument accuracy is ± 0.02 µg l-1 (or ± 3% of the reading, whichever is greater) for chlorophyll a, rhodamine and fluorescein. The accuracy for turbidity, over a 0 - 10 FTU range, is ± 0.02 FTU (or ± 3% of the reading, whichever is greater).
Further details are available from the Aquatracka MKIII 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.
Specifications
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.
Tritech Digital Precision Altimeter PA200
This altimeter is a sonar ranging device that gives the height above the sea bed when mounted vertically. When mounted in any other attitude the sensor provides a subsea distance. It can be configured to operate on its own or under control from an external unit and can be supplied with simultaneous analogue and digital outputs, allowing them to interface to PC devices, data loggers, telemetry systems and multiplexers.
These instruments can be supplied with different housings, stainless steel, plastic and aluminum, which will limit the depth rating. There are three models available: the PA200-20S, PA200-10L and the PA500-6S, whose transducer options differ slightly.
Specifications
Transducer options | PA200-20S | P200-10L | PA500-6S |
Frequency (kHz) | 200 | 200 | 500 |
Beamwidth (°) | 20 Conical | 10 included conical beam | 6 Conical |
Operating range | 1 to 100 m 0.7 to 50 m | - | 0.3 to 50 m 0.1 to 10 m |
Common specifications are presented below
Digital resolution | 1 mm |
Analogue resolution | 0.25% of range |
Depth rating | 700 , 2000, 4000 and 6800 m |
Operating temperature | -10 to 40°C |
Further details can be found in the manufacturer's specification sheet.
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.
Specifications
Pathlength | 10 or 25 cm |
Wavelength | 370, 470, 530 or 660 nm |
Bandwidth | ~ 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) |
Further details are available in the manufacturer's specification sheet or user guide.
Originator's processing document for RRS JR20120207 (JR255B, JR259, JR275) CTD data
Sampling strategy
A total of 22 CTD casts were performed during JR20120207 (JR255B, JR259, JR275), which sailed from Stanley, Falkland Islands on 07 February 2012 and docked in Stanley, Falkland Islands on 22 March 2012. The main objectives for this cruise were to map the seafloor around the southern South Sandwich Islands, Scotia Sea and Weddell Seas and to dredge unsampled seamounts and faulted margins in the same area.
Data processing
For each cast the following raw data files were generated:
- jr259_NNN.dat- raw data
- j259_NNN.hex- raw data
- jr259_NNN.con- configuration
- jr259_NNN.hdr- header
- jr259_NNN.bl- bottle
where NNN is the cast number for the CTD data series. The data were not processed by the originator.
Processing by BODC of RRS James Clark Ross JR20120207 (JR255B, JR259, JR275) CTD data
Raw data were submitted to BODC in the form of SeaBird format. The following procedures were applied using the SBE Data Processing software (Version 7.23.2):
- DatCnv was used to read in the raw CTD data file (.hex) which contained the data in engineering units and apply calibrations as appropriate through the instrument configurations (.con) file
- Bottle summary was run for all files and a .btl file with the average, standard deviation, min and max values recorded by the CTD instrument suite at bottle firings was created
- Filter was run on the pressure channel to smooth out the high frequency data
- AlignCTD was used to advance the oxygen data by 8 seconds
- CellTM was run using alpha = 0.03 and 1/beta = 7, to correct for conductivity errors induced by the transfer of heat from the conductivity cell to the seawater
- Section and Loopedit were used to identify and remove the surface soak
- Derive was run to create the variables Salinity, Salinity 2 and Oxygen SBE 43
- BinAverage and Strip were run to average the data to 2Hz bins (0.5 seconds) and to remove the salinity and oxygen channels which were created when Derive was run
No further processing or calibrations were applied to these data. The final files in .cnv format were then transferred into BODC's internal NetCDF format and original variables were mapped to the appropiate BODC codes, as follows:
Original variable | Units | Descritpion | BODC parameter code | Units | Comment |
---|---|---|---|---|---|
Time elapsed | s | Variable not transferred | |||
Pressure | dbar | Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level | PRESPR01 | dbar | |
Temperature 1 | °C | Temperature of the water body by CTD or STD | TEMPST01 | °C | Primary sensor |
Salinity 1 | psu | Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm | PSALST01 | Primary sensor | |
Conductivity 1 | s m-1 | Electrical conductivity of the water body by CTD | CNDCST01 | s m-1 | Primary sensor |
Oxygen raw | volt | Instrument output (voltage) by microelectrode | OXYVLTN1 | volt | |
Oxygen SBE43 | ml l-1 | Concentration of oxygen {O2 CAS 7782-44-7} per unit volume of the water body [dissolved plus reactive particulate phase] by Sea-Bird SBE 43 sensor and no calibration against sample data | DOXYSU01 | µmol l-1 | * 44.66 |
Fluorescence | µg l-1 | Concentration of chlorophyll-a {chl-a CAS 479-61-8} per unit volume of the water body [particulate >unknown phase] by in-situ chlorophyll fluorometer | CPHLPR01 | mg m-3 | |
PAR/irradiance | µE m-2 s-1 | Downwelling vector irradiance as photons (PAR wavelengths) in the water body by cosine-collector radiometer | IRRDUV01 | µE m-2 s-1 | |
Potential temperature of the water body by computation using UNESCO 1983 algorithm | POTMCV01 | °C | Derived from PRESPR01, TEMPST01 and PSALST01 | ||
Sigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm | SIGTPR01 | kg m-3 | Derived from PRESPR01, TEMPST01 and PSALST01 | ||
Saturation of oxygen {O2 CAS 7782-44-7} in the water body [dissolved plus reactive particulate phase] | OXYSZZ01 | % | Derived from PRESPR01, TEMPST01 and DOXYSU01 |
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 by setting the data to an appropriate value and applying the quality control flag.
Data from the secondary Temperature, Salinity and Conductivity sensors were also transferred but dropped following screening as there was no difference in the data quality between the primary and secondary sensors. Data from these sensors are available upon request.
Project Information
BAS Long Term Monitoring and Survey
Introduction
The Long Term Monitoring and Survey project (LTMS) has been running since the British Antarctic Survey (BAS) was created. This project is one of the BAS core projects, with several groups of scientists collecting various types of data e.g biological, geological, atmospheric, among others.
Data collection is achievable through a wide scope of instruments and platforms, e.g. the Antarctic research stations, autonomous instrument platforms deployed on or from BAS research ships, BAS aircrafts, satellite remote sensing and others.
Scientific Objectives
This project was implemented in order to measure change and variability in the Earth system. Its long term duration allows for the monitoring of processes that could be missed in shorter term studies and experiments. The data collected is also used to check and improve the reliability of models used to stimulate and predict the behavior of the Earth system.
The main objectives are:
- Topographic survey
- Geosciences survey
- Biological survey and monitoring
- Atmospheric and oceanographic monitoring
Data Availability
The data sets obtained through this project are available to the academic community.
Data Activity or Cruise Information
Cruise
Cruise Name | JR20120207 (JR255B, JR259, JR275) |
Departure Date | 2012-02-07 |
Arrival Date | 2012-03-22 |
Principal Scientist(s) | Phil T Leat (British Antarctic Survey) |
Ship | RRS James Clark Ross |
Complete Cruise Metadata Report is available here
Fixed Station Information
No Fixed Station Information held for the Series
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 |
B | nominal value |
Q | value below limit of quantification |