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Metadata Report for BODC Series Reference Number 1837523


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
NameCategories
Sea-Bird SBE 43 Dissolved Oxygen Sensor  dissolved gas sensors
Sea-Bird SBE 911plus CTD  CTD; water temperature sensor; salinity sensor
Tritech PA-200 Altimeter  altimeters
Biospherical QCD-905L underwater PAR sensor  radiometers
Sea-Bird SBE 3plus (SBE 3P) temperature sensor  water temperature sensor
Sea-Bird SBE 4C conductivity sensor  salinity sensor
Chelsea Technologies Group Aquatracka III fluorometer  fluorometers
Paroscientific Digiquartz depth sensors  water pressure sensors
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Dr Dave Barnes
Originating Organization British Antarctic Survey
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) Polar Science for Planet Earth
 

Data Identifiers

Originator's Identifier CTD_JR230_CTD19E_FILTER_ALIGNCTD_CTM_SECTION_LOOPE
BODC Series Reference 1837523
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2009-12-09 03:16
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval 1.0 decibars
 

Spatial Co-ordinates

Latitude 67.74100 S ( 67° 44.5' S )
Longitude 70.16600 W ( 70° 10.0' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth 1.98 m
Maximum Sensor or Sampling Depth 604.01 m
Minimum Sensor or Sampling Height 17.99 m
Maximum Sensor or Sampling Height 620.02 m
Sea Floor Depth 622.0 m
Sea Floor Depth Source DATAHEAD
Sensor or Sampling Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor or Sampling 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 CODERankUnitsTitle
ACYCAA011DimensionlessSequence number
AHSFZZ011MetresHeight (spatial coordinate) relative to bed surface in the water body
CNDCST011Siemens per metreElectrical conductivity of the water body by CTD
CPHLPR011Milligrams per cubic metreConcentration of chlorophyll-a {chl-a CAS 479-61-8} per unit volume of the water body [particulate >unknown phase] by in-situ chlorophyll fluorometer
DOXYZZ011Micromoles per litreConcentration of oxygen {O2 CAS 7782-44-7} per unit volume of the water body [dissolved plus reactive particulate phase] by in-situ sensor
IRRDUV011MicroEinsteins per square metre per secondDownwelling vector irradiance as photons of electromagnetic radiation (PAR wavelengths) in the water body by cosine-collector radiometer
OXYSZZ011PercentSaturation of oxygen {O2 CAS 7782-44-7} in the water body [dissolved plus reactive particulate phase]
OXYVLTN11VoltsRaw signal (voltage) of instrument output by in-situ microelectrode
POTMCV011Degrees CelsiusPotential temperature of the water body by computation using UNESCO 1983 algorithm
PRESPR011DecibarsPressure (spatial coordinate) exerted by the water body by profiling pressure sensor and correction to read zero at sea level
PSALST011DimensionlessPractical salinity of the water body by CTD and computation using UNESCO 1983 algorithm
SIGTPR011Kilograms per cubic metreSigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm
TEMPST011Degrees CelsiusTemperature 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

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:

    1. 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
    2. 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.
    3. WILDEDIT was not needed as no spike pressures were identified in the files.
    4. 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
    5. 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
    6. 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
    7. 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
    8. 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
    9. 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
    10. BINAVERAGE was run against pressure to average data to 1 dbar. Output file: ctd_jr230_CTDNNN_filter_alignCTD_ctm_section_loopedit_derive_binavg.cnv
    11. 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