Metadata Report for BODC Series Reference Number 935777


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
Benthos PSA-916T Sonar Altimeter  altimeters
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Ms Mary Woodgate-Jones
Originating Organization National Oceanography Centre, Southampton
Processing Status banked
Project(s) CLIVAR
Oceans 2025
Oceans 2025 Theme 1
Oceans 2025 Theme 1 WP1.3
 

Data Identifiers

Originator's Identifier CTD_JC031_001_2DB
BODC Series Reference 935777
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2009-02-05 14:42
End Time (yyyy-mm-dd hh:mm) 2009-02-05 16:22
Nominal Cycle Interval 2.0 decibars
 

Spatial Co-ordinates

Latitude 57.13000 S ( 57° 7.8' S )
Longitude 68.25010 W ( 68° 15.0' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 2.97 m
Maximum Sensor Depth 4385.81 m
Minimum Sensor Height 6.18 m
Maximum Sensor Height 4389.03 m
Sea Floor Depth 4392.0 m
Sensor Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor Depth Datum Approximate - Depth is only approximate
Sea Floor Depth Datum Approximate - Depth is only approximate
 

Parameters

BODC CODE Rank Units Short Title Title
ACYCAA01 1 Dimensionless Record_No Sequence number
AHSFZZ01 1 Metres Height Height above bed in the water body
CNDCST01 1 Siemens per metre CTDCond Electrical conductivity of the water body by CTD
CNDCST02 1 Siemens per metre CTDCond2 Electrical conductivity of the water body by CTD (sensor 2)
CPHLPM01 1 Milligrams per cubic metre chl-a_water_ISfluor_manufctrcal_sensor1 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 and manufacturer's calibration applied
DEPHPR01 1 Metres CmpDep Depth below surface of the water body by profiling pressure sensor and converted to seawater depth using UNESCO algorithm
DOXYSC01 1 Micromoles per litre WC_dissO2_calib 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 calibration against sample data
PRESPR01 1 Decibars Pres_Z Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level
PSALCC01 1 Dimensionless P_sal_CTD_calib Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm and calibration against independent measurements
PSALCC02 1 Dimensionless P_sal_CTD_calib2 Practical salinity of the water body by CTD (second sensor) and computation using UNESCO 1983 algorithm and calibration against independent measurements
TEMPCU01 1 Degrees Celsius Uncal_CTD_Temp Temperature of the water body by CTD and NO verification against independent measurements
TEMPCU02 1 Degrees Celsius Uncal_CTD_Temp2 Temperature of the water body by CTD (second sensor) and NO verification against independent measurements
TOKGPR01 1 Litres per kilogram Vol2MassCTD Conversion 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

Measurements made by the primary conductivity sensor (CNDCST02) from stations 1-12 have not been corrected for a pressure trend. This will effect practical salinity (PSALCC02) which is derived from this data. The data originator's have indicated that the secondary sensors (CNDCST01, TEMPCU01 and PSALCC01) should be used in preference.

Data Quality Report

Removal of PAR Sensors

The originators reported that up-welling (UWIRPP01) and down-welling (DWIRPP01) PAR sensors were removed from CTD casts performed in the dark and casts greater than 600 m in depth. The presence/absence of sensors was judged for each CTD cast in turn at BODC. Subsequently, DWIRPP01 and UWIRPP01 were deleted from series where is was clear the sensors had been removed.

Data Quality Report

Low negative values (Chlorophyll-a)

The manufacturer's calibrations applied to the Chelsea MKIII Aquatracka fluorometers did not offset to exactly zero, resulting in low negative values at zero signal. The low negative values are typically less than the accuracy of the instrument but have been flagged suspect because they have fallen below the parameter code limit.


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 .

Benthos Programmable Sonar Altimeter (PSA) 916 and 916T

The PSA 916 is a submersible altimeter that uses the travel time of an acoustic signal to determine the distance of the instrument from a target surface. It provides the user with high resolution altitude or range data while simultaneously outputting data through a digital serial port. A wide beam angle provides for reliable and accurate range measurements under the most severe operational conditions. The instrument is electronically isolated to eliminate any potential signal interference with host instrument sensors. The PSA 916 is an upgrade of the PSA 900.

The standard model (PSA 916) has an operational depth range of 0 - 6000 m, while the titanium PSA 916T has a depth range of 0 - 10000 m. All other specifications for the two versions are the same.

Specifications

Transmit frequency 200 kHz
Transmit pulse width 250 µs
Beam pattern 14° conical
Pulse repetition rate

internal selection: 5 pps

external selection: up to 5 pps- user controlled

Range

100 m full scale

1.0 m guaranteed minimum

0.8 m typical

Range

1 cm for RS232 output

2.5 cm for analog output

Operating depth 6000 m (PSA 916) or 10000 m (PSA 916T)

Further details can be found in the manufacturer's specification sheets for the PSA 916 and the PSA 916T .

Instrument Description

CTD Unit and Auxiliary Sensors

Two CTD packages were used during RRS James Cook cruise 31 (JC031). The first CTD package (stations 1-12) comprised a Sea-Bird 911 plus CTD system, auxiliary sensors and Sea-Bird SBE 32, 24-way carousel fitted to a stainless steel frame with fin. During it's recovery at station 12 (08/02/2009), the package was pulled into the hydroboom block resulting in the total loss of the CTD package over the side. Consequently, the entire package was replaced (see below). A full description of the package is as follows:

Instrument/Sensor Serial Number Manufacturer's
Calibration Date
Comments
Sea-Bird SBE 9 plus underwater unit (aluminium) 09P-24680-0636    
Sea-Bird SBE 11 plus deck unit 11P-34173-0676    
Sea-Bird SBE 3P temperature sensor (aluminium) 03P-4301 4-Apr-08 primary (frame-mounted)
Sea-Bird SBE 4C conductivity sensor (titanium) 04C-3153(T) 22-Apr-08 primary (frame-mounted)
Sea-Bird SBE 3P temperature sensor (aluminium) 03P-4490 4-Apr-08 secondary (fin-mounted)
Sea-Bird SBE 4C conductivity sensor (titanium) 04C-3153(T) 22-Apr-08 secondary (fin-mounted)
Digiquartz temperature compensated pressure sensor 83008 10-Sep-08  
Sea-Bird SBE 32 24-way carousel 32-45661-0621    
20L OTE external spring water samplers     rosette positions 1-24
Sea-Bird SBE 43 dissolved oxygen sensor (titanium) 43-1196 3-Oct-08  
Chelsea MKIII Aquatracka fluorometer (titanium) 88108 9-Jan-08 configured for chl- a
Chelsea MKII Alphatracka transmissometer (titanium) 161045 8-Sep-05 660nm, 25cm path
Wetlabs BBRTD backscatter sensor (titanium) 115R 13-May-08 660nm
PML 2-pi PAR sensor (upwelling) 9 21-Jun-08 only fitted on casts <600m in daylight hours
PML 2-pi PAR sensor (downwelling) 10 14-Apr-08 only fitted on casts <600m in daylight hours
RDI Workhorse Monitor 300kHz ADCP (titanium) 10629   downward-looking master configuration
Benthos PSA-916T 200kHz altimeter (titanium) 1040 Mar-03  
NMF 10kHz pinger B5    
Sea-Bird SBE 5T submersible pump (titanium) 05T-4166   primary
Sea-Bird SBE 5T submersible pump (titanium) 05T-2793   secondary (fin-mounted)

The replacement CTD package (stations 13-84) also comprised a Sea-Bird 911 plus CTD system, auxiliary sensors and Sea-Bird SBE 32, 24-way carousel fitted to a stainless steel frame with fin. The LADCP (s/n 4275) was damaged during the deployment of station 35 and was replaced prior to station 36. A full description of this package is as follows:

Instrument/Sensor Serial Number Manufacturer's
Calibration Date
Comments
Sea-Bird SBE 9 plus underwater unit (titanium) 09P-24680-0637(T)    
Sea-Bird SBE 11 plus deck unit (titanium) 11P-34173-0676    
Sea-Bird SBE 3P temperature sensor (titanium) 03P-4592(T) 28-May-08 primary (frame-mounted)
Sea-Bird SBE 4C conductivity sensor (titanium) 04C-3272(T) 13-Jun-08 primary (frame-mounted)
Sea-Bird SBE 3P temperature sensor (aluminium) 03P-4782 17-Jun-08 secondary (fin-mounted)
Sea-Bird SBE 4C conductivity sensor (aluminium) 04C-3258 6-Jun-08 secondary (fin-mounted)
Digiquartz temperature compensated pressure sensor (titanium) 79501 22-Sep-08  
Sea-Bird SBE 32, 24-way carousel 32-19817-0243    
20L OTE external spring water samplers     rosette positions 21-24
10L OTE external spring water samplers     rosette positions 1-20
Sea-Bird SBE 43 dissolved oxygen sensor (titanium) 43-0619 11-Nov-08  
Chelsea MKIII Aquatracka fluorometer (titanium) 88244 10-Jun-08 configured for chl- a
Chelsea MKII Alphatracka transmissometer (titanium) 07-6075-001 18-Oct-07 660nm, 25cm path
Wetlabs BBRTD backscatter sensor (titanium) 182 20-Jun-07 660nm
PML 2-pi PAR upwelling sensor 9 21-Jun-08 only used on casts <600m and in daylight
PML 2-pi PAR downwelling sensor 10 14-Apr-08 only used on casts <600m and in daylight
RDI Workhorse Monitor 300kHz LADCP (aluminium) 4275   downward-looking master configuration (stations 13-35)
RDI Workhorse Monitor 300kHz LADCP (titanium) 10607   downward-looking master configuration (stations 36-84)
Benthos PSA-916T 200kHz altimeter (titanium) 41302 26-Apr-07  
Sea-Bird SBE 5T submersible pump (titanium) 05T-3002   primary
Sea-Bird SBE 5T submersible pump (titanium) 05T-4513   secondary (fin-mounted)

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 .

BODC Processing

The data arrived at BODC in 84 MSTAR NetCDF format files. These represented all of the CTD casts taken during the cruise. The files did not include transmissometer or backscatter data as this was not processed by the originators. The files were reformatted to the internal QXF format using transfer function 445. Due to a pressure trend on the primary conductivity sensor, the PSO and data originator for the cruise have indicated that the secondary temperature, conductivity and salinity sensors should be used in preference to the primary sensors for stations 1-12. In addition, they have indicated that the primary sensors should be used in preference to secondary sensors for stations 13-84 because of a slight pressure trend and the poor stability of the secondary conductivity sensor at these stations. For these reasons, the files were transferred to QXF format in two groupings - stations 1-12 and stations 13-84. For stations 1-12, the secondary sensors were mapped to '*01' BODC parameter codes while the primary sensors were mapped to '*02' BODC parameter codes. For stations 13-84, the primary sensors were mapped to '*01' parameter codes instead. The following table shows how the variables of station 1-12 were mapped to appropriate BODC parameter codes:

Originator's Variable Units Description BODC Parameter Code Units Comment
pumps - pump status (=1 when pump on) - - Not transferred - not environmental variable
press decibar Pressure sensor PRESPR01 decibar  
pressure_temp deg C (ITS-90) pressure sensor electronics temperature - - Not transferred - not environmental variable
temp deg C (ITS-90) primary temperature sensor (frame-mounted) TEMPCU02 deg C (ITS-90)  
cond mS/cm primary conductivity sensor (frame-mounted) CNDCST02 S/m cond divided by 10
temp2 deg C (ITS-90) secondary temperature sensor (fin-mounted) TEMPCU01 deg C (ITS-90) To be used in preference to primary sensor
cond2 mS/cm secondary conductivity sensor (fin-mounted) CNDCST01 S/m cond2 divided by 10
To be used in preference to primary sensor
oxygen µmol/kg dissolved oxygen sensor DOXYSC01 µmol/l µmol/kg * ((sigma-theta + 1000)/1000)
Density was calculated from PRESPR01, TEMPCU01 and CNDCST01 using Fofonoff and Millard (1983) algorithm
altimeter metres depth from sea floor AHSFZZ01 metres  
nbf - number of CTD bottles fired - - Not transferred - not environmental variable
par_uplook W/m 2 down-welling PAR sensor DWIRPP01 W/m 2  
par_downlook W/m 2 up-welling PAR sensor UWIRPP01 W/m 2  
fluo µg/l chlorophyll- a concentration CPHLPM01 mg/m 3 1 µg/l = 1 mg/m 3
psal pss-78 practical salinity derived from press, cond and temp PSALCC02 pss-78  
psal2 pss-78 practical salinity derived from press, cond2 and temp2 PSALCC01 pss-78 To be used in preference to salinity from primary sensors
depth metres depth of CTD calculated from press and latitude DEPHPR01 metres  
potemp deg C (ITS-90) potential temperature derived from press, psal and temp - - Not transferred - can be calculated from PRESPR01, PSALCC02 and TEMPCU02
potemp2 deg C (ITS-90) potential temperature derived from press, psal2, temp2 - - Not transferred - can be calculated from PRESPR01, PSALCC01 and TEMPCU01

The following table shows how the variables of stations 13-84 were mapped to appropriate BODC parameter codes:

Originator's Variable Units Description BODC Parameter Code Units Comment
pumps - pump status (=1 when pump on) - - Not transferred - not environmental variable
press decibar Pressure sensor PRESPR01 decibar  
pressure_temp deg C (ITS-90) pressure sensor electronics temperature - - Not transferred - not environmental variable
temp deg C (ITS-90) primary temperature sensor (frame-mounted) TEMPCU01 deg C (ITS-90) To be used in preference to secondary sensor
cond mS/cm primary conductivity sensor (frame-mounted) CNDCST01 S/m cond divided by 10
To be used in preference to secondary sensor
temp2 deg C (ITS-90) secondary temperature sensor (fin-mounted) TEMPCU02 deg C (ITS-90)  
cond2 mS/cm secondary conductivity sensor (fin-mounted) CNDCST02 S/m cond2 divided by 10
oxygen µmol/kg dissolved oxygen sensor DOXYSC01 µmol/l µmol/kg * ((sigma-theta + 1000)/1000)
Density was calculated from PRESPR01, TEMPCU01 and CNDCST01 using Fofonoff and Millard (1983) algorithm
altimeter metres depth from sea floor AHSFZZ01 metres  
nbf - number of CTD bottles fired - - Not transferred - not environmental variable
par_uplook W/m 2 down-welling PAR sensor DWIRPP01 W/m 2  
par_downlook W/m 2 up-welling PAR sensor UWIRPP01 W/m 2  
fluo µg/l chlorophyll- a concentration CPHLPM01 mg/m 3 1 µg/l = 1 mg/m 3
psal pss-78 practical salinity derived from press, cond and temp PSALCC01 pss-78 To be used in preference to salinity from secondary sensors
psal2 pss-78 practical salinity derived from press, cond2 and temp2 PSALCC02 pss-78  
depth metres depth of CTD calculated from press and latitude DEPHPR01 metres  
potemp deg C (ITS-90) potential temperature derived from press, psal and temp - - Not transferred - can be calculated from PRESPR01, PSALCC01 and TEMPCU01
potemp2 deg C (ITS-90) potential temperature derived from press, psal2, temp2 - - Not transferred - can be calculated from PRESPR01, PSALCC02 and TEMPCU02

To enable the oxygen unit conversion from µmol/kg to µmol/l, the parameter TOKGPR01 (density reciprocal) was created in the output QXF files.

The reformatted data were then visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag. Missing data were marked by both setting the data to an appropriate value and setting the quality control flag.

Reference

Fofonoff N.P. and Millard Jr. R.C., 1983. Algorithms for computations of fundamental properties of seawater. UNESCO Technical Papers in Marine Science, 44, 53pp.

Originator's Data Processing

Sampling Strategy

The aim of JC031 was to occupy repeats of hydrographic sections in Drake Passage. The sections studied are as follows: Section SR1 (also known as A21), which is located in Drake Passage between the Southern tip of South America and the West Antarctic Peninsula; section SR1b is located further to the east. In addition to the previous section of SR1b, extra stations were sampled on the northern side of the Burdwood Bank, located south of the Falkland Islands. The data collected during JC031 comprised physical, chemical and biological measurements. There were five main scientific teams, physics, nutrients and oxygen, carbon, CFC's and transient tracers, and biology (phytoplankton). The data will contribute to the current knowledge of the physical, chemical and biological properties in this region, and will also allow comparisons to be drawn with previous cruise data so that the change in water properties and transport through Drake Passage from west to east can be observed.

A total of 84 CTD (conductivity-temperature-depth) casts were performed during the cruise. Of these casts, 48 (stations 2-49) were taken along the SR1 transect and 35 casts (stations 50-84) were taken along the SR1b transect. A 24-bottle rosette was used to take water samples at CTD stations with the general aim of sampling the full water column. Also mounted on the frame was a LADCP (lowered acoustic doppler current profiler), fluorometer, transmissometer, PAR and a dissolved oxygen sensor. Station 1 was a test cast, allowing scientists to practice sampling. At station 12, the CTD package ran into the blocks and the CTD was lost. CTD data were collected but there were no water samples or LADCP data from this station. Consequently, station 13 was a test cast with the new package (max wire out ~100m). The CTD cast was aborted at station 34 due to loss of communications at the start of the upcast. The cast was also aborted at station 35 when electrical termination flooded at 936m on the downcast. Station 36 was a successful repeat of stations 35 and 34.

Data Processing

Initial data processing was performed on a PC using the Seabird processing software SBE Data Processing, Version 7.18. Further information about Sea-Bird processing can be found in section 1 (p1) of the technical report for this cruise. After initial processing with the Seabird routines, all data were run through MSTAR MEXEC processing, which consisted of a suite of NOCS-generated programs. This was performed in Matlab and used NetCDF file formats to store all data. Further information about MEXEC processing can be found in sections 2, 3 and 4 (from p2-6) of the technical report from this cruise.

Field Calibrations

Salinity

CTD salinity was calibrated against independent bottle samples. Bottle samples were taken from all unique depths on every CTD cast. They were analysed using a Guildline 8400B Autosal. Further information about the collection and analysis of salinity bottle samples can be found here . Further information about the calibration of CTD salinity can be found in section 2.3 on page 3 of the technical report for this cruise.

Oxygen

CTD oxygen was calibrated against independent bottle samples. Bottle samples were taken from every CTD niskin bottle that had been fired and was sampled for other analyses. Samples were analysed using the Winkler whole bottle titration method with amperometric endpoint detection. Further information about the collection and analysis of independent bottles samples can be found here . Further information about the calibration of CTD oxygen can be found in section 2.4 (pages 4-5) of the technical report for this cruise.

Chlorophyll- a

The fluorescence sensor was not calibrated with independent bottle samples. Chlorophyll- a bottle samples were collected during the cruise but for purposes other than CTD fluorescence sensor calibration. Consequently, it may be possible to calibrate the sensor should these samples become available at a later date.


Project Information

Climate Variability and Predictability (CLIVAR)

CLIVAR is an international research programme investigating climate variability and predictability on different time-scales and the response of the climate system to anthropogenic forcing. Climate variability, its extremes and possible future changes, has a strong impact on mankind. CLIVAR seeks to better understand and predict our climate in order to take precautions and to reduce impacts of climate variability and change on our planet. CLIVAR is one of the major components of the World Climate Research Programme (WCRP). It started in 1995 and will have a lifetime of 15 years.

The specific objectives of CLIVAR are:

Further information may be obtained from the Official CLIVAR Project web site and theBODC web site


Oceans 2025 - The NERC Marine Centres' Strategic Research Programme 2007-2012

Who funds the programme?

The Natural Environment Research Council (NERC) funds the Oceans 2025 programme, which was originally planned in the context of NERC's 2002-2007 strategy and later realigned to NERC's subsequent strategy (Next Generation Science for Planet Earth; NERC 2007).

Who is involved in the programme?

The Oceans 2025 programme was designed by and is to be implemented through seven leading UK marine centres. The marine centres work together in coordination and are also supported by cooperation and input from government bodies, universities and other partners. The seven marine centres are:

Oceans2025 provides funding to three national marine facilities, which provide services to the wider UK marine community, in addition to the Oceans 2025 community. These facilities are:

The NERC-run Strategic Ocean Funding Initiative (SOFI) provides additional support to the programme by funding additional research projects and studentships that closely complement the Oceans 2025 programme, primarily through universities.

What is the programme about?

Oceans 2025 sets out to address some key challenges that face the UK as a result of a changing marine environment. The research funded through the programme sets out to increase understanding of the size, nature and impacts of these changes, with the aim to:

In order to address these aims there are nine science themes supported by the Oceans 2025 programme:

In the original programme proposal there was a theme on health and human impacts (Theme 7). The elements of this Theme have subsequently been included in Themes 3 and 9.

When is the programme active?

The programme started in April 2007 with funding for 5 years.

Brief summary of the programme fieldwork/data

Programme fieldwork and data collection are to be achieved through:

The data is to be fed into models for validation and future projections. Greater detail can be found in the Theme documents.


Oceans 2025 Theme 1: Climate, Ocean Circulation and Sea Level

Through fieldwork, analysis and modelling, Theme 1 will provide detailed knowledge of how the Atlantic, Arctic and Southern Oceans are responding to, and driving, climate change. In combination with geodetic studies, it will also improve our ability to predict global sea level and UK land movements in the century ahead.

The official Oceans 2025 documentation for this Theme is available from the following link: Oceans 2025 Theme 1

Weblink: http://www.oceans2025.org/


Oceans 2025 Theme 1, Work Package 1.3: Physical-biogeochemical budgets and mixing in the Southern Ocean

This Work Package is run by the National Oceanography Centre, Southampton (NOCS) and aims to establish regional budgets of heat, freshwater and carbon, and to develop more accurate parameterisations for predictive ocean models by quantitatively investigating diapycnal and isopycnal transport processes using observations.

Vast, though poorly quantified, amounts of anthropogenic CO2 (~20 Pg) are believed to have been absorbed into the Antarctic mode and intermediate waters. Much of this uptake is achieved in the Antarctic Circumpolar Current (ACC), involving the upwelling of North Atlantic Deep Water, its northward transport by a delicate balance between Ekman drift and eddies, followed by subduction as mode waters. Models suggest that the rate of CO2 uptake is sensitive to changes in the wind and to changes to the eddy fluxes (Mignone et al., 2005).

To predict climate change, it is essential that the size of this carbon sink be known, and the processes that control it be understood. Even the exchanges of heat and freshwater between the Atlantic and Southern Oceans are poorly known. NOCS will combine observations and modelling to quantify and understand the processes controlling property fluxes and trends in the Atlantic sector of the Southern Ocean, where the Atlantic overturning circulation is partially closed as it meets the ACC. The observational effort will be fully integrated with the international Climate Variability and Predictability (CLIVAR)/Carbon repeat hydrography program, and with the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES) initiative to study mixing rates and processes; this work has been accepted as a contribution to the International Polar Year. The budgets and mixing rates inferred from field measurements will be used to both evaluate and improve numerical models.

More detailed information on this Work Package is available at pages 10 - 11 of the official Oceans 2025 Theme 1 document: Oceans 2025 Theme 1

Weblink: http://www.oceans2025.org/

References

Mignone B., Gnanadesikan A., Sarmiento JL., and Slater RD., 2005. Central role of Southern Hemisphere winds and eddies in modulating the oceanic uptake of anthropogenic carbon, Geophys Res Lett, 32 doi:101029/2005Gl024464


Data Activity or Cruise Information

Cruise

Cruise Name JC031
Departure Date 2009-02-03
Arrival Date 2009-03-03
Principal Scientist(s)Elaine McDonagh (National Oceanography Centre, Southampton)
Ship RRS James Cook

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