Metadata Report for BODC Series Reference Number 1789353
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 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 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 JR20061003 (JR152, JR159)
CTD Unit and Auxiliary Sensors
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. Attached to the CTD were two SBE 3P temperature sensors, two SBE 4C conductivity sensors, one Paroscientific Digiquartz pressure sensor and one SBE 43 dissolved oxygen sensor.
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 | |||
Pressure sensor | Paroscientific Digiquartz | 93686-0771 | 2004/04/15 | ||
Temperature sensor | SBE 3P | 4302 | SBE 03P | 2006/06/01 | Primary sensor |
Temperature sensor | SBE 3P | 2191 | SBE 03P | 2006/06/01 | Secondary sensor |
Conductivity sensor | SBE 4C | 2875 | SBE 04C | 2006/06/01 | Primary sensor |
Conductivity sensor | SBE 4C | 1912 | SBE 04C | 2006/06/01 | Secondary sensor |
Dissolved oxygen sensor | SBE 43 | 0676 | SBE 43 | 2004/03/23 |
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.
Originator's processing document for RRS James Clark Ross JR20061003 (JR152, JR159) CTD data
Sampling strategy
A total of 2 CTD casts were performed during JR20061003 (JR152, JR159), which sailed from Stanley, Falkland Islands on 03 October 2006 and docked in Stanley, Falkland Islands on 20 October 2006. The main objectives for this cruise was to sample larval fish with nets, deploy moorings and calibrate the ship's acoustic system (EK60). A pCO2 system was also implemented and operated by the Plymouth Marine Laboratory (PML) during this cruise.
Data processing
For each cast the following raw data files were generated:
- jr159_NNN.dat- raw data
- jr159_NNN.con- configuration
- jr159_NNN.hdr- header
where NNN is the cast number for the CTD data series. No processing was performed by the originator and files were submitted in raw format.
Processing by BODC of RRS James Clark Ross JR20061003 (JR152, JR159) 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
- 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
- Loopedit was used to 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 | |
Salinity 1 | psu | Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm | PSALST01 | ||
Conductivity 1 | s m-1 | Electrical conductivity of the water body by CTD | CNDCST01 | s m-1 | |
Oxygen | volt | Instrument output (voltage) by in-situ 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 |
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 between the quality between the primary and secondary sensors. These channels as well as the derived parameters they originated are available upon request.
Project Information
DISCOVERY 2010
DISCOVERY 2010 will investigate and describe the response of an ocean ecosystem to climate variability, climate change and commercial exploitation. The programme builds on past studies by BAS on the detailed nature of the South Georgia marine ecosystem and its links with the large-scale physical and biological behaviour of the Southern Ocean.
The aim is to identify, quantify and model key interactions and processes on scales that range from microscopic life forms to higher predators (penguins, albatrosses, seals and whales), and from the local to the circumpolar.
Objectives
Assess the links between the status of local marine food webs and variability and change in the Southern Ocean. Develop a linked set of ecosystem models applying relevant marine physics and biology over scales from the local to that of the entire Southern Ocean.
Relevance to Global Science
Ocean ecosystems play a crucial role in maintaining biodiversity, in depositing carbon into the deep ocean, and as a source of protein for humans. However, fishing and climate change are having significant and often detrimental effects. To predict the future state of ocean ecosystems we must develop computer models capable of simulating biological and physical processes on a range of scales from the local to an entire ocean. Developing such predictive models is crucial to the sustainable management of world fisheries and requires integrated analyses of the way whole ecosystems work. DISCOVERY 2010 aims to take this work forward and at the same time help manage the South Georgia and South Sandwich Islands maritime zone. We will do this through providing information on the state of the ecosystem to the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), the international body that manages sustainable fishing in the Southern Ocean.
Delivering the Results
DISCOVERY 2010 will undertake an integrated programme of shipboard and land-based field studies of the marine food web, combined with modelling. We will pay particular attention to critical phases in the life cycles of key species, and to examining interactive effects in food webs. Interacting biological and physical processes will be modelled across a range of spatial scales to significantly improve our representation of the ocean ecosystem, upon which sustainable management and the prediction of future climate change can be based. DISCOVERY 2010 will link to BIOFLAME, ACES, and COMPLEXITY, two international programmes, and to a collaborative programme with the University of East Anglia on the role of the Southern Ocean in the global carbon cycle.
Component Projects
- DISCOVERY-OEM: Ocean Ecosystems and Management
- DISCOVERY-FOOD-WEBS: Scotia Sea FOOD-WEBS
- DISCOVERY-FLEXICON: FLEXIbility and CONstraints in life histories
- DISCOVERY-CEMI: Circumpolar Ecosystems; Modelling and Integration
Data Activity or Cruise Information
Cruise
Cruise Name | JR20061003 (JR152, JR159) |
Departure Date | 2006-10-03 |
Arrival Date | 2006-10-20 |
Principal Scientist(s) | David Pond (National Oceanography Centre, Southampton) |
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 |