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Metadata Report for BODC Series Reference Number 1840997


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
NameCategories
Sea-Bird SBE 43 Dissolved Oxygen Sensor  dissolved gas sensors
Chelsea Technologies Group Aquatracka fluorometer  fluorometers
Sea-Bird SBE 911plus CTD  CTD; water temperature sensor; salinity sensor
Tritech PA-200 Altimeter  altimeters
WETLabs C-Star transmissometer  transmissometers
Sea-Bird SBE 3plus (SBE 3P) temperature sensor  water temperature sensor
Sea-Bird SBE 4C conductivity sensor  salinity sensor
Biospherical Instruments QCP-2350 [underwater] PAR sensor  radiometers
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Dr Yvonne Firing
Originating Organization National Oceanography Centre, Southampton
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) NERC-CONICYT ICEBERGS
 

Data Identifiers

Originator's Identifier CTD_JR17001_004_2DB
BODC Series Reference 1840997
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2017-11-24 12:31
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval 2.0 decibars
 

Spatial Co-ordinates

Latitude 62.20820 S ( 62° 12.5' S )
Longitude 58.74790 W ( 58° 44.9' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth 2.97 m
Maximum Sensor or Sampling Depth 103.97 m
Minimum Sensor or Sampling Height 5.03 m
Maximum Sensor or Sampling Height 106.03 m
Sea Floor Depth 109.0 m
Sea Floor Depth Source BRIDGE
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]
POPTDR011PercentTransmittance (red light wavelength) per 25cm of the water body by 25cm path length red light transmissometer
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
TOKGPR011Litres per kilogramConversion factor (volume to mass) for the water body by CTD and computation of density (in-situ potential temperature surface pressure) reciprocal from pressure, temperature and salinity

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

CTD data from cruise JR17001 Quality Report

Screening and Quality Control

During BODC quality control, data were screened using in house visualisation software. The data were screened and any obvious outliers and spikes were looked at in closer detail and flagged if necessary.

Improbable flags ('M') were applied to the CPHLPR01 channel where values were negative. There were a number of outliers in the POPTDR01 channel but it was not deemed that these outliers were anomalous and therefore did not required flagging.

AHSFZZ01

This channel has been flagged where values are constant or increase with depth. The altimeter only collects good data within 100 m of the seabed and these instances of constant values or increases with depth occur more than 100 m from the seabed.


Data Access Policy

Data access conditions (generic)

Access to these data is currently restricted and the data may not be released by BODC without obtaining specific permission from the data originator.


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 JR17001 CTD

CTD Unit and Auxiliary Sensors

The CTD unit comprised a Sea-Bird Electronics (SBE) 9plus underwater unit, an SBE 11 plus deck unit, a 24-way SBE 32 carousel and 24 Niskin bottles; all of which were mounted on a stainless steel 24-way CTD frame. Attached to the CTD were two SBE 3P temperature sensors, two SBE 4C conductivity sensors, one SBE 43 dissolved oxygen sensor, one QCP2350 PAR sensor, one CTG Aquatracka MKIII fluorometer, one WetLabs C-Star transmissometer, one Tritech Altimeter, one SBE35 temperature sensor and a RDI LADCP.

Sensor unit Model Serial number Full specification
CTD underwater unit SBE 9plus 0707 SBE 9plus
CTD deck unit SBE 11plus 0458 -
Carousel SBE 32 - 24 Position Pylon 0636 SBE 32
Temperature sensor SBE 3P 2705 SBE 03P
Temperature sensor SBE 3P 5042 SBE 03P
Conductivity sensor SBE 4C 3488 SBE 04C
Conductivity sensor SBE 4C 2248* SBE 04C
Dissolved oxygen sensor SBE 43 0242 SBE 43
Altimeter Tritech PA-200 10127 Tritech PA-200
Irradiance sensor Biospherical QCP2350 PAR 70636 Biospherical QCP PAR sensor
Fluorometer Chelsea MKIII Aquatracka 09-7324-001 Chelsea MKII Aquatracka
Transmissometer WetLabs C-Star 396 WetLabs C-Star
Temperature sensor (Independent) SBE 35 0024 SBE 35
LADCP RDI Workhorse 300 kHz 15060** LADCP

* The secondary conductivity sensor was replaced during the cruise due to the output of the first sensor being spikey. The serial number of the first sensor was 2248 and the serial number of the second sensor was 2255.

** The LADCP was replaced during the cruise due to excessive file fragmentation. The LADCP was replaced by RDI Workhorse 300 kHz serial number 14897.

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.

Aquatracka fluorometer

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 QCP-2350 [underwater] PAR sensor

A cosine-corrected PAR quantum irradiance profiling sensor. For use in underwater applications with 24 bit ADC systems. Measures light available for photosynthesis on a flat surface. Operation is by a single channel compressed analog output voltage that is proportional to the log of incident PAR (400-700 nm) irradiance. The sensor is designed for operation in waters to depths of up to 2,000 m (standard) or 6,800 m (optional).

For more information, please see this document: https://www.bodc.ac.uk/data/documents/nodb/pdf/Biospherical_QCP2300_QCP2350_Apr2014.pdf

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.

BODC Data Processing of CTD casts from cruise JR17001

Data Processing

Files from 43 of the 44 CTD casts from cruise JR17001 were processed and submitted to BODC in .nc format. The cast that was not submitted was a test cast. The files were subsequently archived and transferred to BODC internal format using standard BODC procedures. The variables provided in the files were mapped to BODC parameter codes as follows:

Originator's Variable Originator's Units BODC Parameter Code BODC Units Comment
altimeter m AHSFZZ01 m -
cond mS cm-1 CNDCST01 S m-1 Conversion of * 0.1 applied.
fluor µg L-1 CPHLPR01 mg m-3 Equivalent units
oxygen µmol kg-1 DOXYZZ01 µmol L-1 Conversion of CTDOXY * ((sigma-T + 1000)/1000) applied.
par number IRRDUV01 µE m-2 s -1 -
press dbar PRESPR01 dbar -
psal pss-78 PSALST01 Dimensionless -
temp degC90 TEMPST01 °C -
transmittance percent POPTDR01 % -

The following parameters were derived by BODC when the data were transferred to internal BODC netcdf format:

BODC Parameter Code BODC Units Comment
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.
TOKGPR01 L kg-1 Derived by BODC using SIGTPR01.

The following originator's variables were not transferred to BODC internal format but are available on request:

  • cond1, cond2 - the originator specfied cond as the preferred channel
  • psal1, psal2 - the originator specfied psal as the preferred channel
  • temp1, temp2 - the originator specfied temp as the preferred channel
  • potemp, potemp1, potemp2 - the parameter is derived by BODC instead
  • depth
  • pressure_temp

Screening

Post transfer analysis and crosschecks were applied according to BODC procedures. This involved the screening of data using BODC's in house visualisation software where any suspect data were flagged but not removed. During screening, any data that were flagged as improbable by the originator were converted to BODC data flags.

Originator Data Processing of CTD casts from cruise JR17001

Sampling Strategy

A total of 44 CTD casts were performed during JR17001 with 34 of these casts were completed as part of the ORCHESTRA programme and the remaining 10 casts completed for the NERC-CONICYT ICEBERGS programme. 20 of the ORCHESTRA casts surveyed the SR1b line.

Data Processing

The CTD data were acquired using Seabird SeaSave version 7.22.3. Subsequently, the following three processes were run in SBE Data Processing:

  • Data conversion - converted raw data from engineering units to binary .cnv files.
  • AlignCTD - applied a time alignment offset to the oxygen data relative to pressure to compensate for hysteresis effects.
  • CellTM - corrected conductivity data for cell thermal mass effects.

Any settings used during these steps were provided by the manufacturer.

Data were then processed using a suite of Matlab programs developed by the Ocean Circulation and Processing group at the National Oceanography Centre (NOC).

Calibrations

Temperature

The CTD temperature sensor was calibrated by comparison with SBE35 values obtained at the time of bottle firings. The calibration of the temperature sensors are as follows:

Calibration equation as a function of station number, n
Sensor 1 tempcalib = tempraw + 0.00013n + 0.00441
Sensor 2 tempcalib = tempraw +0.00019n + 0.00686

Conductivity

Conductivity calibrations were applied by comparing laboratory analysed values from Niskin water samples and CTD values at the time of bottle firing. The calibration of the sensors are as follows:

Calibration equation as a function of station number, n, and pressure, p
Sensor 1 condcalib = condraw x (((0.007 - 0.0003n + interp([0 700 5000],[0.001 -0.0005 -0.001], p))/35 + 1)
Sensor 2 condcalib = condraw x (((0.0025 - 0.0001n + interp([0 400 5000],[0.0005 0.001 -0.001], p))/35 + 1)

Oxygen

Dissolved oxygen calibrations were applied in post-cruise processing by comparing Winkler titration values from Niskin water samples and CTD values at the time of bottle firing.


Further information on the CTD processing can be found in section 12.2 of the cruise report.


Project Information

Impacts of deglaciation on benthic marine ecosystems in Antarctica

Impacts of deglaciation on benthic marine ecosystems in Antarctica (ICEBERGS) is one of three NERC-CONICYT joint funded projects running for three years from 2017 to 2020. The aim of the programme is to investigate the impacts of physical disturbance arising from climate-warming induced deglaciation on benthic communities around the West Antarctic Peninsula.

Participants

There are four research institutions involved in the project:

  • University of Bangor
  • University of Exeter
  • Universidad Católica de la Santísima Concepción
  • British Antarctic Survey (BAS)

Research Details

In order to meet the aim of the project, the ICEBERGS consortium produced six objectives:

  • Monitoring glacier retreat over time and scour intensity on the adjacent seabed.
  • Determine the benthic assemblage structure from localities with different perturbation levels.
  • Evaluate nutritional and reproductive conditions of adults.
  • Analyse growth rates from bivalve/gastropod shells and bryozoan populations with different perturbation levels.
  • Develop reconstructions of physical disturbance due to iceberg discharge from growth patterns present in the carbonate structure of the shells of marine molluscs.
  • Estimate the effect of marine glacier discharge and iceberg scouring on the genetic diversity and connectivity of marine invertebrate populations and the role of dispersal potential.

Fieldwork and Data Collection

The fieldwork for the project consists of research cruises along the west Antarctic Peninsula across three field seasons on board the RRS James Clark Ross. Three sites (Marine Cove, William Glacier and Sheldon Glacier) were selected for the fieldwork using available bathymetry and glacier retreat data. The fieldwork covers physical oceanography, marine geology, habitat mapping, community structure and seabed sediments and consists of CTD deployments, multi-beam swath bathymetry surveys, TOPAS sub-bottom profiling, shallow underwater camera system deployments, plankton net deployments, Agassiz trawls, Hamon grabs and multi-corer deployments.


Data Activity or Cruise Information

Cruise

Cruise Name JR17001 (ORCHESTRA)
Departure Date 2017-11-21
Arrival Date 2017-12-21
Principal Scientist(s)Alexander Brearley (British Antarctic Survey), David Barnes (British Antarctic Survey), Yvonne L Firing (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
Q value below limit of quantification