Metadata Report for BODC Series Reference Number 1618559


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 2-pi PAR irradiance sensor  radiometers
Sea-Bird SBE 911plus CTD  CTD; water temperature sensor; salinity sensor
WETLabs ECO BB(RT)D Scattering Meter  optical backscatter sensors
WETLabs C-Star transmissometer  transmissometers
Chelsea Technologies Group Aquatracka III fluorometer  fluorometers
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Dr Rob Thomas
Originating Organization British Oceanographic Data Centre, Liverpool
Processing Status QC in progress
Project(s) -
 

Data Identifiers

Originator's Identifier JR303_AMT24_CTD029
BODC Series Reference 1618559
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2014-10-10 05:12
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval 1.0 decibars
 

Spatial Co-ordinates

Latitude 10.76050 N ( 10° 45.6' N )
Longitude 27.19570 W ( 27° 11.7' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth 0.99 m
Maximum Sensor Depth 500.53 m
Minimum Sensor Height 5300.47 m
Maximum Sensor Height 5800.01 m
Sea Floor Depth 5801.0 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 Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum Chart reference - Depth extracted from available chart
 

Parameters

No Parameters for BODC Reference Number = 1618559

 

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

RRS James Clark Ross Cruise JR303 (JR20140922), AMT24 CTD Data Quality Document

Temperature, salinity, potential temperature and sigma-theta:Profiles look good with one spike in the primary salinity sensor for CTD003. Sensors also appear to have had a delay in readings noticed at the top of the profile for CTD0031 and CTD0032.

N.B.Sensor 1 values for salinity were Null for CTD001, CTD002, and CTD003. The sensor values for sensor 2 replaced the Null values in sensor 1 in order to derive oxygen, sigma-theta and potential temperature. Thus Sensor 2 values are Null for these casts.

Chlorophyll: Negative concentrations were flagged as suspect. Some spiking occurred, particularly below the chlorophyll maximum and was subsequently flagged. No discrete samples were taken to calibrate data from this profile so the data for calibrated fluorometer were all Null for CTD046.

Dissolved oxygen concentration and oxygen saturation: CTD003 had some noise around 700 m which was flagged as suspect. Overall profiles look good.

Attenuance and transmissance: Overall profiles look good. A few spikes occurred below 200 m, which were flagged suspect.

Attenuance due to backscatter: Generally some very low values. CTD casts CTD001 to CTD010 were all negative, thus the values were flagged as suspect. Negative values for other casts were also flagged as suspect.

Downwelling vector irradiance as photons (PAR wavelengths): Overall profiles look good.


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 .

RRS James Clark Ross Cruise JR303 AMT24 BAS CTD Instrumentation

The CTD unit was a Sea-Bird Electronics 911 plus system, consisting of an SBE 11 plus deck unit and a 9 plus underwater unit. The CTD was fitted with an altimeter, downwelling PAR sensors, a BB-RTD sensor, transmissometer and a fluorometer as auxilliary sensors. All instruments were attached to a 24 position stainless steel Sea-Bird SBE 32 carousel water sampler equipped with 24 Ocean Test Equipment 20L water samplers, (s/n's 1 through 24). The table below lists more detailed information about the various sensors.

Sensor Model Serial Number Calibration Date Comments Casts Used
Primary CTD deck unit SBE 11plus 11P-   Primary CTD deck unit 1-22, 24-70
Secondary CTD deck unit SBE 11plus 11P-0587   Secondary CTD deck unit 1-22, 24-70
CTD Underwater Unit SBE 9plus 09P-0541 21-05-2014 n/a 1-22, 24-70
24-way frame NOCS     n/a 1-22, 24-70
Digiquartz Pressure sensor Paroscientific     Frequency 2 1-22, 24-70
Primary Temperature Sensor SBE 3P 3P-5043 08-05-2014 Frequency 0 1-22, 24-70
Secondary Temperature Sensor SBE 3P 3P-2307 07-05-2014 Frequency 3 1-22, 24-70
Primary Conductivity Sensor SBE 4C 4C-1913 23-04-2014 Frequency 1 1-4
Primary Conductivity Sensor SBE 4C 4C-3491 23-04-2014 Frequency 1 5-22, 24-70
Secondary Conductivity Sensor SBE 4C 4C-3491 23-04-2014 Frequency 4 1-3
Secondary Conductivity Sensor SBE 4C 4C-4090 23-04-2014 Frequency 4 4-22, 24-70
24-way Carousel SBE 32 32   n/a 1-22, 24-70
Primary Pump SBE 5T 5T-   Primary 1-22, 24-70
Secondary Pump SBE 5T 5T-   Secondary 1-22, 24-70
BBRTD Light Scatter Sensor Wetlabs BBRTD849R   Voltage 0 1-22, 24-70
Free       Voltage 1 n/a
Transmissometer WetLabs C-Star CST1497DR 02-06-2014 Voltage 2 1-22, 24-70
Fluorometer CTG Aquatracka MKlll 12-8513-001 09-05-2014 Voltage 3 1-22, 24-70
Free       Voltage 4 n/a
PAR (Downwelling) Chelsea 03   Voltage 5 1-22, 24-70
Dissolved Oxygen Sensor SBE 43 43-0620 02-05-2014 Voltage 6 1-22, 24-70
Altimeter       Voltage 7 1-22, 24-70
LADCP battery pack (Titanium)       n/a 1-22, 24-70
20L Water Samplers OTE 1 through 24   n/a 1-22, 24-70
LADCP TRDI WHM 300kHz 14897 09-09-2013 n/a 1-22, 24-70

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 .

Chelsea Technologies Photosynthetically Active Radiation (PAR) Irradiance Sensor

This sensor was originally designed to assist the study of marine photosynthesis. With the use of logarithmic amplication, the sensor covers a range of 6 orders of magnitude, which avoids setting up the sensor range for the expected signal level for different ambient conditions.

The sensor consists of a hollow PTFE 2-pi collector supported by a clear acetal dome diverting light to a filter and photodiode from which a cosine response is obtained. The sensor can be used in moorings, profiling or deployed in towed vehicles and can measure both upwelling and downwelling light.

Specifications

Operation depth 1000 m
Range 2000 to 0.002 µE m -2 s -1
Angular Detection Range ± 130° from normal incidence
Relative Spectral Sensitivity

flat to ± 3% from 450 to 700 nm

down 8% of 400 nm and 36% at 350 nm

Further details can be found in the manufacturer's specification sheet .

WETLabs Single-angle Backscattering Meter ECO BB

An optical scattering sensor that measures scattering at 117°. This angle was determined as a minimum convergence point for variations in the volume scattering function induced by suspended materials and water. The measured signal is less determined by the type and size of the materials in the water and is more directly correlated to their concentration.

Several versions are available, with minor differences in their specifications:

Specifications

Wavelength 471, 532, 660 nm
Sensitivity (m -1 sr -1 )

1.2 x 10 -5 at 470 nm

7.7 x 10 -6 at 532 nm

3.8 x 10 -6 at 660 nm

Typical range ~0.0024 to 5 m -1
Linearity 99% R 2
Sample rate up to 8Hz
Temperature range 0 to 30°C
Depth rating

600 m (standard)

6000 m (deep)

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 .

RRS James Clark Ross Cruise JR303 (JR20140922), AMT24 CTD Processing Document

Sampling Protocol for Data Acquisition and Analysis

A total of 70 CTD casts were completed during the cruise. All casts bar cast CTD023 were conventional profiling casts with water sampling by 24 x 20L OTE Niskin bottles. Cast CTD023 used the NOC Titanium rig profiling casts with water sampling by 29 x 10 L TMF Water Samplers OTE. Casts were carried out at around 04:00-05:00 and around 13:00-14:00 ship time each day weather permitting.

BODC Cruise Processing

CTD casts were recorded using the Sea-Bird data collection software Seasave-Win32. The software outputs were then processed following the BODC recommended guidelines using SBE Data Processing-Win32 v7.23.2; the processing routines are named after each stage in brackets < >. The software applied the calibrations as appropriate through the instrument configuration file to the data in engineering units output by the CTD hardware.

An ASCII file (CNV) containing the 24 Hz data for up and down casts was generated from the binary Sea-Bird files for each cast <DatCnv>. Files were created for each cast containing the mean values of all the variables at the bottle firing events <Bottle Summary>. Using the CNV files processing routines were applied to remove pressure spikes <WildEdit>, the oxygen sensor was then shifted relative to the pressure by 2 seconds, to compensate for the lag in the sensor response time <AlignCTD> and the effect of thermal 'inertia' on the conductivity cells was removed <CellTM>. The surface soak was identified for each cast, removed and LoopEdit run. Salinity and oxygen concentration were re-derived and density (sigma-theta) values were derived <Derive> after the corrections for sensor lag and thermal 'inertia' had been applied. The CTD files produced from Sea-Bird processing were converted from 24 Hz ASCII files into 1 dbar downcast files for calibration and visualisation onboard <BinAverage>. The initial salinity and oxygen channels produced at the DatCnv stage, along with the conductivity, voltage and altimeter channels were removed from the 1 dbar downcast files <Strip>.

The sensor values at bottle firing produced by the Bottle Summary routine were collated and used to generate calibrations for the salinity, oxygen and fluorometer channels. Water samples were collected from each cast for measurement of salinity (bench salinometer) and chlorophyll-a (filtration, acetone extraction and fluorometer measurement) and from the pre-dawn cast each day for oxygen (Winkler titration).

Parameter Name in Sea-Bird CNV Units Parameter Name in ODV file Units Comments
prDM: Pressure, Digiquartz db Pressure dbar -
t090C: Temperature ITS-90, deg C Temperature_1 deg C -
t190C: Temperature, 2 ITS-90, deg C Temperature_2 deg C -
c0S/m: Conductivity S/m - - Not transferred through to ODV
c1S/m: Conductivity, 2 S/m - - Not transferred through to ODV
sal00: Salinity, Practical PSU Salinity1_benchcal   -
sal11: Salinity, Practical PSU Salinity2_benchcal   -
sbeox0Mm/L: Oxygen, SBE 43 µmol/l Oxy_conc_Winklercal µmol/l -
CStarTr0: Beam Transmission, WET Labs C-Star % Beam transmission % BAS CTD only
CStarAt0: Beam Transmission, WET Labs C-Star 1/m Beam transmission 1/m BAS CTD only
flC: Fluorescence, Chelsea Aqua 3 Chl Con µg/l Fluorometer_notional_calibration mg m -3 -
par: PAR/Irradiance, Biospherical/Licor   PAR_down W m -2 -
turbWETbb0: Turbidity, WET Labs ECO BB m^-1/sr Backscatter@532nm m^-1/sr -
sbeox0V: Oxygen raw, SBE 43 V - - Not transferred through to ODV

Calibrated salinity, oxygen and fluorometer channels were then added to the profiles using calibration equations derived from the bottle file data compared against discrete samples collected from the CTD water bottles on each cast.

Calibrations

The method used for calibration was to generate an offset between the discrete water sample measurement (salinity/oxygen/chl-a) and the nominal value from the sensor at bottle firing. The offsets were then plotted against the discrete sample values and a linear regression applied.

Offset = a * Discrete sample + b

Where offset = Discrete sample - Sensor value

To give Calibrated value = 1/(1-a) * Sensor value + b/(1-a)

Where the regression was not significant the mean value of the offset was applied. All calibration datasets are available upon request from BODC post cruise.

Temperature

There were no independent measurements of temperature made during the cruise and the sensors on the rig returned consistent data. No further calibration of these sensors has been carried out.

Salinity

The salinity channels were calibrated against bench salinometer measurements from 2 - 4 samples collected from each cast. Further details of these measurements can be found in the NMF-SS cruise report section.

At the start of the cruise there was some discrepancy between the initial sensors on the CTD set up. The sensors were switched with the spare sensor to determine which may be faulty. Sensors 4C-3491 and 4C-4090 were used for the remainder of the cruise without further problems. The calibration equations for the sensors were:

Sensor SBE 4C-3491 - Calibrated = 0.9983 * sensor + 0.0579 (n = 93; r 2 = 0.242; p < 0.001);

Sensor SBE 4C-4090 - Calibrated = 0.9979 * sensor + 0.0749 (n = 92; r 2 = 0.335; p < 0.004);

Oxygen

The oxygen sensor was calibrated against discrete oxygen sample Winkler titration measurements from up to 9 samples collected from the pre-dawn CTD.

The oxygen sensor operated without problem throughout the cruise

The Winkler titration samples from cast 19 did not fit the pattern observed with the data from the other casts and were excluded from the calibration dataset.

The calibration equation was:

Calibrated O 2 (in µmol/l) = 1.0385 * sensor O 2 (in µmol/l) + 6.8857 (n=161; r 2 =0.33; p < 0.001);

Fluorescence

The CTD deployed Chelsea AQUAtracka MkIII fluorometer was calibrated against extracted chlorophyll-a measurements made on seawater collected by Niskin bottles on each cast, shown below. Samples of seawater from CTD niskin bottles were collected to calibrate the CTD fluorometer with the analytical method following Welschmeyer (1994). Samples were collected at 54 stations from an average of 10 depths including light depths from 97, 55, 33, 14, 7, 1 and 0.1%. Each sample of 250 ml was filtered through 47 mm 0.2 µm polycarbonate filters. The filters were then placed in a vial with 10 ml 90% acetone and left in a freezer for 24 hours. The samples were then analysed on a pre-calibrated Turner Designs Trilogy fluorometer with a non-acidified chl module (CHL NA #046) fitted. The pre-calibrated fluorometer produced anomalous results during analysis throughout the cruise, however as there were no dilutions of pure chlorophyll stock available, the calibration was not checked or modified. To compensate for this, the fluorometer was back-calibrated at PML after the cruise and the results were updated based on the new fluorometer calibration.

The Chelsea AQUAtracka MkIII fluorometer attached to the CTD rig operated without problem.

References

Welschmeyer N.A., 1994. Fluorometric analysis of chlorophyll-a in the presence of chlorophyll-b and phaeopigments. Limnology and Oceanography, 39(8), 1985-1992.

CTD Calibration Equation N R 2
CTD001 CPHLPS01 = 2.659 * CPHLPM01 - 0.112 8 0.9968
CTD002 CPHLPS01 = 1.635 * CPHLPM01 - 0.001 8 0.9903
CTD003 CPHLPS01 = 1.582 * CPHLPM01 + 0.058 6 0.8216
CTD004 CPHLPS01 = 1.664 * CPHLPM01 + 0.084 8 0.9098
CTD005 CPHLPS01 = 2.235 * CPHLPM01 - 0.017 7 0.9814
CTD006 CPHLPS01 = 2.822 * CPHLPM01 - 0.042 6 0.9673
CTD007 CPHLPS01 = 2.089 * CPHLPM01 + 0.009 7 0.9878
CTD008 CPHLPS01 = 1.981 * CPHLPM01 + 0.039 8 0.9441
CTD009 CPHLPS01 = 1.492 * CPHLPM01 + 0.042 8 0.8431
CTD010 CPHLPS01 = 1.778 * CPHLPM01 + 0.053 7 0.8801
CTD011 CPHLPS01 = 2.123 * CPHLPM01 + 0.044 8 0.9896
CTD012 CPHLPS01 = 2.339 * CPHLPM01 + 0.062 8 0.9853
CTD013 CPHLPS01 = 2.454 * CPHLPM01 + 0.07 9 0.9826
CTD014 CPHLPS01 = 2.451 * CPHLPM01 + 0.057 9 0.9348
CTD015 CPHLPS01 = 3.045 * CPHLPM01 + 0.029 9 0.9722
CTD016 CPHLPS01 = 3.206 * CPHLPM01 + 0.002 9 0.9882
CTD017 CPHLPS01 = 3.097 * CPHLPM01 + 0.03 9 0.9937
CTD018 CPHLPS01 = 3.289 * CPHLPM01 + 0.027 9 0.98
CTD019 CPHLPS01 = 2.711 * CPHLPM01 + 0.036 9 0.9513
CTD020 CPHLPS01 = 3.569 * CPHLPM01 - 0.01 9 0.9855
CTD021 CPHLPS01 = 4.188 * CPHLPM01 - 0.015 8 0.991
CTD022 CPHLPS01 = 3.649 * CPHLPM01 + 0.001 6 0.9781
CTD023 * N/A N/A N/A
CTD024 CPHLPS01 = 3.142 * CPHLPM01 + 0.04 9 0.9672
CTD025 CPHLPS01 = 2.161 * CPHLPM01 + 0.048 9 0.9274
CTD026 CPHLPS01 = 3.806 * CPHLPM01 - 0.042 9 0.9619
CTD027 CPHLPS01 = 2.694 * CPHLPM01 + 0.034 9 0.8534
CTD028 CPHLPS01 = 1.727 * CPHLPM01 + 0.051 9 0.8396
CTD029 CPHLPS01 = 3.211 * CPHLPM01 - 0.059 9 0.9021
CTD030 CPHLPS01 = 1.869 * CPHLPM01 + 0.059 9 0.9146
CTD031 CPHLPS01 = 3.889 * CPHLPM01 - 0.079 8 0.953
CTD032 CPHLPS01 = 3.804 * CPHLPM01 - 0.062 9 0.9476
CTD033 CPHLPS01 = 2.948 * CPHLPM01 + 0.003 9 0.8996
CTD034 CPHLPS01 = 1.765 * CPHLPM01 + 0.028 9 0.6577
CTD035 CPHLPS01 = 1.954 * CPHLPM01 - 0.01 7 0.7319
CTD036 CPHLPS01 = 2.306 * CPHLPM01 - 0.052 9 0.8497
CTD037 CPHLPS01 = 2.311 * CPHLPM01 - 0.034 7 0.912
CTD038 CPHLPS01 = 2.019 * CPHLPM01 + 0.029 9 0.8855
CTD039 CPHLPS01 = 2.254 * CPHLPM01 + 0.054 9 0.9346
CTD040 CPHLPS01 = 2.639 * CPHLPM01 + 0.007 9 0.9342
CTD041 CPHLPS01 = 2.014 * CPHLPM01 + 0.05 9 0.9518
CTD042 CPHLPS01 = 1.542 * CPHLPM01 + 0.054 8 0.9739
CTD043 CPHLPS01 = 2.207 * CPHLPM01 + 0.04 9 0.9634
CTD044 CPHLPS01 = 1.948 * CPHLPM01 + 0.039 8 0.9723
CTD045 CPHLPS01 = 2.882 * CPHLPM01 + 0.008 9 0.9578
CTD046 * N/A N/A N/A
CTD047 CPHLPS01 = 2.163 * CPHLPM01 + 0.042 9 0.9943
CTD048 CPHLPS01 = 2.102 * CPHLPM01 + 0.032 9 0.9806
CTD049 CPHLPS01 = 2.781 * CPHLPM01 + 0.022 9 0.9924
CTD050 CPHLPS01 = 2.996 * CPHLPM01 + 0.013 8 0.9773
CTD051 CPHLPS01 = 2.539 * CPHLPM01 + 0.02 8 0.992
CTD052 CPHLPS01 = 2.543 * CPHLPM01 + 0.028 9 0.9927
CTD053 CPHLPS01 = 1.823 * CPHLPM01 + 0.028 9 0.9693
CTD054 CPHLPS01 = 1.739 * CPHLPM01 + 0.055 9 0.9064
CTD055 CPHLPS01 = 2.157 * CPHLPM01 + 0.019 9 0.9811
CTD056 CPHLPS01 = 1.187 * CPHLPM01 + 0.037 8 0.5586
CTD057 CPHLPS01 = 1.671 * CPHLPM01 + 0.002 9 0.9502
CTD058 CPHLPS01 = 1.966 * CPHLPM01 + 0.009 7 0.9729
CTD059 CPHLPS01 = 1.887 * CPHLPM01 - 0.007 8 0.9816
CTD060 CPHLPS01 = 1.78 * CPHLPM01 + 0.017 7 0.7144
CTD061 CPHLPS01 = 1.608 * CPHLPM01 + 0.009 9 0.8425
CTD062 CPHLPS01 = 1.316 * CPHLPM01 + 0.044 8 0.9312
CTD063 CPHLPS01 = 1.868 * CPHLPM01 + 0.01 9 0.9766
CTD064 CPHLPS01 = 1.38 * CPHLPM01 + 0.034 9 0.8869
CTD065 CPHLPS01 = 1.445 * CPHLPM01 + 0.027 9 0.9264
CTD066 CPHLPS01 = 1.171 * CPHLPM01 + 0.058 8 0.7173
CTD067 CPHLPS01 = 1.238 * CPHLPM01 + 0.011 8 0.6593
CTD068 CPHLPS01 = 1.363 * CPHLPM01 + 0.042 5 0.525
CTD069 CPHLPS01 = 2.527 * CPHLPM01 + 0.067 9 0.9052
CTD070 CPHLPS01 = 1.573 * CPHLPM01 + 0.023 8 0.9304

* N.B. No calibrations were applied to CTD023 or CTD046

BODC post-processing and screening

Reformatting

The data were converted from tab delimited ODV format into BODC internal format using BODC transfer function 480. Only the final calibrated channels were transferred and the following table shows how these variables were mapped to appropriate BODC parameter codes. Oxygen saturation and sigma-theta were derived and added to the profiles during the transfer process. For calculation of oxygen saturation CTD01, CTD02 and CTD03 used the secondary sensor as the primary sensor provided Null values for these first casts.

Originator's Parameter Name Units Description BODC Parameter Code Units Comments
Pressure dbar Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level PRESPR01 dbar  
Temperature_1 deg C Temperature of the water body by CTD or STD TEMPST01 Degrees Celsius  
Temperature_2 deg C Temperature of the water body by CTD or STD TEMPST02 Degrees Celsius  
Beam transmission % Transmittance (red light wavelength) per 25cm of the water body by 25cm path length red light transmissometer. POPTDR01 Percent  
Beam transmission 1/m Attenuance (red light wavelength) per unit length of the water body by 25cm path length red light transmissometer ATTNDR01 per metre  
Fluorometer_notional_calibration mg m -3 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 CPHLPM01 Milligrams per cubic metre  
Fluorometer_sample_calibration mg m -3 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 calibration against sample data CPHLPS01 Milligrams per cubic metre  
PAR_down W m -2 Downwelling vector irradiance as photons (PAR wavelengths) in the water body by cosine-collector radiometer DWIRRXUD Watts per square metre  
Backscatterat532nm m -1 /sr Attenuance due to backscatter (532 nm wavelength at 117 degree incidence) by the water body [particulate >unknown phase] by in-situ optical backscatter measurement BB117G01 per metre per nanometre per steradian  
Salinity1_benchcal   Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm and calibration against independent measurements PSALCC01 Dimensionless Salinometer2 was used for CTD01, CTD02 and CTD03 as Salinometer1 values were all Null.
Salinity2_benchcal   Practical salinity (second sensor) of the water body by CTD and computation using UNESCO 1983 algorithm and calibration against independent measurements PSALCC02 Dimensionless  
Oxy_conc_Winklercal µmol/l 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 DOXYSC01 Micromoles per litre  
- - Potential temperature of the water body by computation using UNESCO 1983 algorithm POTMCV01 Degrees Celsius  
- - Sigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm SIGTPR01 Kilograms per cubic metre  
- - Saturation of oxygen {O2 CAS 7782-44-7} in the water body [dissolved plus reactive particulate phase] by Sea-Bird SBE 43 sensor and computation from concentration using Benson and Krause algorithm OXYSSU01 Percent This was calculated for CTD023
- - Saturation of oxygen {O2 CAS 7782-44-7} in the water body [dissolved plus reactive particulate phase] by Sea-Bird SBE 43 sensor and calibration against sample data and computation from concentration using Benson and Krause algorithm OXYSSC01 Percent This was calculated for all casts, excluding CTD023

N.B. Due to CTD01, CTD02, and CTD03 Sensor 2 values being used to replace Sensor 1 values the values for Sensor 2 are thus given as Null.

References

Benson, B.B. and Krause, D., 1984. The concentration and isotopic fractionation of oxygen dissolved in freshwater and seawater in equilibrium with the atmosphere. Limnology and Oceanography, 29(3), pp. 620-632.

Fofonoff, N.P. and Millard, R.C., 1983. Algorithms for computations of fundamental properties of seawater. UNESCO Technical Papers in Marine Science No. 44, pp. 53

Screening

Reformatted CTD data were transferred onto a graphics work station for visualisation using the in-house editor EDSERPLO. No data values were edited or deleted. Flagging was achieved by modification of the associated BODC quality control flag for suspect or null values.


Project Information


No Project Information held for the Series

Data Activity or Cruise Information

Cruise

Cruise Name JR20140922 (AMT24, JR303)
Departure Date 2014-09-22
Arrival Date 2014-11-01
Principal Scientist(s)Tim Smyth (Plymouth Marine Laboratory)
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