Metadata Report for BODC Series Reference Number 1837431
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
CTD Unit and Auxiliary Sensors
A Sea-Bird 911plus CTD system was used on cruise JR230. This was mounted on a stainless steel rosette frame, equipped with Niskin bottles.
Sensor information
Sensor | Serial Number | Last calibration date | Comments |
---|---|---|---|
Primary Temperature Sea-Bird SBE 3plus | 5042 | 12/04/2008 | - |
Secondary Temperature Sea-Bird SBE 3plus | 5043 | 09/04/2008 | - |
Primary Conductivity Sea-Bird SBE 4C | 3488 | 22/04/2008 | - |
Secondary Conductivity Sea-Bird SBE 4C | 3491 | 22/04/2008 | - |
PA-200 Altimeter | 2130.27001 | Not Specified | - |
Sea-Bird SBE 43 dissolved oxygen sensor | 0245 | 12/06/2007 | - |
Chelsea Aqua 3 fluorometer | 88-2615-126 | 13/09/2007 | - |
Digiquartz with TC Pressure Sensor | 0541-75429 | 18/07/2007 | - |
Biospherical PAR sensor | 7274 | Not Specified | - |
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.
RRS James Clark Ross JR20091202 (JR230) CTD BODC Processing
The data for the CTD stations were submitted to BODC in raw SeaBird format and converted to .cnv format using SBE Data Processing software (SeaBird software: 7.26.6.28). No 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 appropriate BODC codes, as follows:
Originator's variable | Units | BODC Code | Units | Comments |
---|---|---|---|---|
press | dbars | PRESPR01 | dbars | - |
altimeter | m | AHSFZZ01 | m | - |
temp | °C | TEMPST01 | °C | - |
temp2 | °C | TEMPST02 | °C | Duplicate channel not retained |
cond | s m-1 | CNDCST01 | s m-1 | - |
cond2 | s m-1 | CNDCST02 | s m-1 | Duplicate channel not retained |
oxygen | ml l-1 | DOXYZZ01 | µmol l-1 | Conversion by BODC to µmol l-1 |
oxygen raw | Volt | OXYVLTN1 | Volt | - |
PAR | µE m-2s-1 | IRRDUV01 | µE m-2s-1 | - |
fluor | µg l-1 | CPHLPR01 | mg m-3 | µg l-1 = mg m-3 |
psal | pss-78 | PSALST01 | Calculated from calibrated conductivity measurements, by the originator | |
psal2 | pss-78 | PSALST02 | Duplicate channel not retained | |
OXYSZZ01 | % | Derived by BODC using DOXYZZ01, TEMPST01 and PSALST01 | ||
POTMCV01 | °C | Derived by BODC using TEMPST01, PSALST01 and PRESPR01. | ||
SIGTPR01 | kg m-3 | Derived by BODC using POTMCV01, PSALST01 and PRESPR01 |
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.
RRS James Clark Ross JR20091202 (JR230) Originator's CTD Data Processing
Sampling Strategy
Data were collected from 13 CTD stations during JR20091202 (JR230) which sailed from Rothera Research Station to shelf break, West Antarctic Peninsula on 02 December 2009 and docked back in Rothera, Antarctica on 11 December 2009. The data were submitted to BODC in raw SeaBird format and processed by BODC using the SBE Data Processing software (SeaBird software: 7.26.6.28).
Data Processing
For each cast the following raw data files were generated:
- ctd_jr230_NNN.hex (raw binary data file)
-
- ctd_jr230_NNN.bl (a record of bottle firing locations)
- ctd_jr230_NNN.con (configuration file)
- ctd_jr230_NNN.hdr (header file)
Where NNN is the cast number for the CTD data series. The data were processed by BODC following standard procedures. No calibration was performed on any of the sensors.
The following processing was performed by BODC:
- DATCNV was run to convert raw files to ASCII and apply manufacturer's calibrations as appropriate through the .con file.The process was re-run as originator had selected oxygen in µmol/kg. In order to derive concentration, µmol l-1 and voltages were needed. Output file :ctd_jr230_CTDNNN.cnv
- BOTTLESUM was run to obtain CTD records for bottles fired. Tau correction was applied to these data and the average, standard deviation, minimum and maximum values at bottle firing were extracted from the .bl files.
- WILDEDIT was not needed as no spike pressures were identified in the files.
- FILTER was run to smooth out high-frequency pressure data and a low pass filter of 0.15 s was applied to the pressure channel. Output file: ctd_jr230_CTDNNN_filter.cnv
- ALIGN CTD ran with +2, +5 and +8 seconds on Oxygen channel only. The 5s alignment was chosen as it was deemed the most appropriate to the data. Output file: ctd_jr230_CTDNNN_filter_alignCTD.cnv
- CELL THERMAL MASS was run to carry out a conductivity cell thermal mass correction. Values for alpha and 1/beta were: 0.03 and 7.0, respectively. Output file: ctd_jr230_CTDNNN_filter_alignCTD_ctm.cnv
- SECTION was run because the files showed that a soak was included in the data. This was run for each individual file and removed the soak from the data. The downcast and upcast data were still both present. Output: ctd_jr230_CTDNNN_filter_alignCTD_ctm_section.cnv
- LOOPEDIT was run to flag scans where pressure slows down or reverses. The procedure was run with the following criteria, minimum CTD velocity of 0 m s-1and remove surface soak unticked (as it was done with SECTION and exclude scans marked bad ticked). The following file type was created: ctd_jr230_CTDNNN _filter_alignCTD_ctm_section_loopedit.cnv
- DERIVE was run to obtain salinity and oxygen saturation and concentration in ml l-1. The output file was saved as ctd_jr230_CTDNNN_filter_alignCTD_ctm_section_loopedit_derive.cnv
- BINAVERAGE was run against pressure to average data to 1 dbar. Output file: ctd_jr230_CTDNNN_filter_alignCTD_ctm_section_loopedit_derive_binavg.cnv
- STRIP was run to remove the primary and secondary salinity and oxygen concentration channels from the files. The channels were removed as new corrected ones were derived after all corrections (align and filter) were applied. Output file: ctd_jr230_CTDNNN_filter_alignCTD_ctm_section_loopedit_derive_binavg_strip.cnv
Field Calibrations
Data were not calibrated as no water samples were collected for this purpose.
Project Information
Polar Science for Planet Earth (PSPE)
Introduction
The PSPE programme is the British Antarctic Survey strategic science framework that extends from April 2009 to March 2013. This programme was created to respond to the Natural Environment Research Council (NERC) strategy from 2007 to 2012, and contributes to a major environmental research programme, Living with Environmental Change (LWEC), which comprises a 10 year partnership between the UK's main organisations that fund, carry out and use environmental research and observations and will improve the country's tools and knowledge to build resilience, mitigate problems and adapt to environmental change.
The PSPE programme will focus on key questions that can be answered by research requiring access to the polar regions, developing research and long term monitoring and survey programmes in the Antarctic but also pursuing new bi-polar and Arctic research opportunities. The support given to the research programmes includes: investment in training, development of scientific skills and expertise, maintenance of the existing research infrastructures (research stations, ships, aircraft and laboratories), development of new techniques to collect, transfer, curate and visualize data from and relating to the polar regions.
PSPE consists of 6 programmes:
- Climate: atmospheric science and processes, including climate modelling
- Chemistry and past climate: quaternary climate including ice cores, lake, sediments, marine sediments and tropospheric chemistry
- Ecosystems: dynamics of polar ecosystems in response to the impacts of climate and fisheries
- Environmental Change and Evolution: the Earth system; geological to upper atmosphere, complexities and scales of interactions, controls on biological evolution
- Ice sheets: ice sheet evolution and flow, ice sheet changes and sea level rise
- Oceans: role of the polar oceans in controlling and influencing the Earth system
Data Availability
The data produced during this project are available to the academic community.
Data Activity or Cruise Information
Cruise
Cruise Name | JR20091202 (JR230) |
Departure Date | 2009-12-02 |
Arrival Date | 2009-12-11 |
Principal Scientist(s) | David Barnes (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 |