Metadata Report for BODC Series Reference Number 1133225


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
WETLabs ECO BB(RT)D Scattering Meter  optical backscatter sensors
Paroscientific 410K Pressure Transducer  water temperature sensor; water pressure sensors
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
Chelsea Technologies Group Alphatracka II transmissometer  transmissometers
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Dr Matt Palmer
Originating Organization National Oceanography Centre, Liverpool
Processing Status banked
Project(s) UKOARP_ThemeB
 

Data Identifiers

Originator's Identifier CTD_D366020_AVG
BODC Series Reference 1133225
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2011-06-13 18:18
End Time (yyyy-mm-dd hh:mm) 2011-06-13 18:21
Nominal Cycle Interval 0.5 decibars
 

Spatial Co-ordinates

Latitude 53.60980 N ( 53° 36.6' N )
Longitude 5.71620 W ( 5° 43.0' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth 1.01 m
Maximum Sensor Depth 67.11 m
Minimum Sensor Height 13.89 m
Maximum Sensor Height 79.98 m
Sea Floor Depth 81.0 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 Instantaneous - Depth measured below water line or instantaneous water body surface
 

Parameters

BODC CODE Rank Units Short Title Title
ACYCAA01 1 Dimensionless Record_No Sequence number
ATTNDR01 1 per metre Attn_Red_25cm Attenuation (red light wavelength) per unit length of the water body by 25cm path length red light transmissometer
BB117R01 1 per metre per nanometre per steradian AttenBS_660nm_117deg Attenuation due to backscatter (660 nm wavelength at 117 degree incidence) by the water body [particulate >unknown phase] by in-situ optical backscatter measurement
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
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
DWIRPP01 1 Watts per square metre DWIrr_2-piPAR Downwelling 2-pi scalar irradiance as energy (PAR wavelengths) in the water body by 2-pi scalar radiometer
FVLTAQ01 1 Volts AqVolt Instrument output (voltage) by in-situ Aquatracka chlorophyll fluorometer
OXYSSC01 1 Percent BK_SBE43 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
POPTDR01 1 Percent Trans_Red_25cm Transmittance (red light wavelength) per 25cm of the water body by 25cm path length red light transmissometer
POTMCV01 1 Degrees Celsius WC_Potemp Potential temperature of the water body by computation using UNESCO 1983 algorithm
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
PSALST01 1 Dimensionless P_sal_CTD Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm
SIGTPR01 1 Kilograms per cubic metre SigTheta Sigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm
TEMPST01 1 Degrees Celsius WC_temp_CTD Temperature of the water body by CTD or STD
UWIRPP01 1 Watts per square metre ScalarUwirPAR Upwelling 2-pi scalar irradiance as energy (PAR wavelengths) in the water body by 2-pi scalar radiometer
 

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

RSS Discovery Cruise D366 CTD Data Quality Document

There are some small entrainment features visible in some casts where there are sharp gradients within the profiles for salinity, temperature (and hence density and potential temperature), oxygen concentration and saturation.

Downwelling PAR irradiance

PAR sensors were not present on three casts: CTD_D366030_AVG, CTD_D366060_AVG and CTD_D366061_AVG, as these casts were to deeper pressures than the sensors are designed for. It is unclear whether the surface variability in the PAR channels is due to changing cloud cover or more likely, a shading effect from the ship during initial deployment.

Chlorophyll

The profile trends appear reasonable, however the absolute values returned from the manufacturer's calibration may need further correction as several series contain values below the minimum limit of the parameter range (0 to 999 mg m-3). The deep spikes on some of the profiles such as cast CTD_D366072_AVG have been flagged as suspect.

Attenuance

The profile trends appear reasonable, however the absolute values returned from the manufacturer's calibration may need further correction as some series have negative data values which are out of the range of the parameter range (0 to 400 metre-1). There are deep spikes on a couple of profiles such as cast CTD_D366010_AVG, that have been flagged suspect.

Transmittance

The profile trends appear reasonable, however the absolute values returned from the manufacturer's calibration may need further correction as some series have data values above 100% and therefore outside the range of the parameter. There are also some deep spikes on some of the profiles such as CTD_D366010_AVG, that have been marked as suspect.

Turbidity

The profile trends appear reasonable, however the absolute values returned from the manufacturer's calibration may need further correction as many of the series have negative data values and are therefore out the of range of the parameter (0 to 9 m-1nm-1sr-1).


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 D366

Standard Rosette CTD Unit and Auxiliary Sensors;

A 24-way stainless steel frame (s/n SBE CTD4 (1415)), with a Sea-Bird 9/11 plus underwater unit (SN 09P-46253-0869) with vane-mounted secondary temperature and conductivity sensors was used throughout the cruise. All other instruments were attached to a Sea-Bird 32 Carousel 24 Position Pylon (s/n 32-34173-0493) with Ocean Test Equipment 20L ES-120B water samples. The Stainless Steel CTD system used an 11 plus deck unit (s/n 11P-34173-0676).

The CTD unit included the following sensors

Sensor Model Serial Number Calibration Comments
Pressure transducer Digiquartz temperature compensated pressure sensor 100898 31/07/2009 -
Conductivity sensor SBE 4C 04C-2571 22/02/2011 Primary sensor
Conductivity sensor SBE 4C 04C-3054 31/03/2011 Secondary sensor vane mounted
Temperature sensor SBE 3P 03P-2919 07/04/2011 Primary sensor
Temperature sensor SBE 3P 03P-4151 07/04/2011 Secondary sensor, vane mounted
Dissolved oxygen SBE 43 43-1882 10/07/2010 -
Fluorometer Chelsea MKIII Aquatracka Fluorometer 88-2050-095 21/04/2011 -
Transmissometer Chelsea MKII 25cm path Alphatracka transmissometer 07-6075-001 05/10/2010 -
Backscatter meter WETLabs BBRTD light scattering sensor, red LED, 650nm BBRTD-169 14/04/2010 -
Photosynthetically Active Radiation Chelsea 2-pi PAR irradiance sensor, DWIRR PAR 06 01/10/2010 -
Photosynthetically Active Radiation Chelsea 2-pi PAR irradiance sensor, UWIRR PAR 07 01/10/2010 -
Altimeter Tritech PA200 altimeter 6196.118171 14/11/2006 -

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 Group ALPHAtracka and ALPHAtracka II transmissometers

The Chelsea Technologies Group ALPHA tracka (the Mark I) and its successor, the ALPHA tracka II (the Mark II), are both accurate (< 0.3 % fullscale) transmissometers that measure the beam attenuation coefficient at 660 nm. Green (565 nm), yellow (590 nm) and blue (470 nm) wavelength variants are available on special order.

The instrument consists of a Transmitter/Reference Assembly and a Detector Assembly aligned and spaced apart by an open support frame. The housing and frame are both manufactured in titanium and are pressure rated to 6000 m depth.

The Transmitter/Reference housing is sealed by an end cap. Inside the housing an LED light source emits a collimated beam through a sealed window. The Detector housing is also sealed by an end cap. A signal photodiode is placed behind a sealed window to receive the collimated beam from the Transmitter.

The primary difference between the ALPHA tracka and ALPHA tracka II is that the Alphatracka II is implemented with surface-mount technology; this has enabled a much smaller diameter pressure housing to be used while retaining exactly the same optical train as in the Mark I. Data from the Mark II version are thus fully compatible with that already obtained with the Mark I. The performance of the Mark II is further enhanced by two electronic developments from Chelsea Technologies Group - firstly, all items are locked in a signal nulling loop of near infinite gain and, secondly, the signal output linearity is inherently defined by digital circuitry only.

Among other advantages noted above, these features ensure that the optical intensity of the Mark II, indicated by the output voltage, is accurately represented by a straight line interpolation between a reading near full-scale under known conditions and a zero reading when blanked off.

For optimum measurements in a wide range of environmental conditions, the Mark I and Mark II are available in 5 cm, 10 cm and 25 cm path length versions. Output is default factory set to 2.5 volts but can be adjusted to 5 volts on request.

Further details about the Mark II instrument are available from the Chelsea Technologies Group ALPHA tracka II 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 .

Paroscientific Absolute Pressure Transducers Series 3000 and 4000

Paroscientific Series 3000 and 4000 pressure transducers use a Digiquartz pressure sensor to provide high accuracy and precision data. The sensor comprises a quartz crystal resonator that responds to pressure-induced stress, and temperature is measured for thermal compensation of the calculated pressure.

The 3000 series of transducers includes one model, the 31K-101, whereas the 4000 series includes several models, listed in the table below. All transducers exhibit repeatability of better than ±0.01% full pressure scale, hysteresis of better than ±0.02% full scale and acceleration sensitivity of ±0.008% full scale /g (three axis average). Pressure resolution is better than 0.0001% and accuracy is typically 0.01% over a broad range of temperatures.

Differences between the models lie in their pressure and operating temperature ranges, as detailed below:

Model Max. pressure (psia) Max. pressure (MPa) Temperature range (°C)
31K-101 1000 6.9 -54 to 107
42K-101 2000 13.8 0 to 125
43K-101 3000 20.7 0 to 125
46K-101 6000 41.4 0 to 125
410K-101 10000 68.9 0 to 125
415K-101 15000 103 0 to 50
420K-101 20000 138 0 to 50
430K-101 30000 207 0 to 50
440K-101 40000 276 0 to 50

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

UK Ocean Acidification (UKOA) cruise D366 CTD processing

Sampling strategy

A total of 75 successful CTD casts were made during the cruise using a stainless steel frame. Rosette bottles were fired throughout the water column on the upcast of most profiles. Data were measured by a PC running Seasave V 7.20g, Sea-Bird's data acquisition software.

Originator's processing

The initial Sea-Bird processing was completed at NOCL. The latest available version of the SeaBird Processing software (SBE Data Processing V7.22.0) was used to process the raw binary data files (DAT files) based on information held in the sensor configuration files (CON files), and bottle firing files (BL). During 21 of the casts, the required soak was either not performed or only partially undertaken.

Sea-Bird processing

The raw data files have the appendices: .hex, .HDR, .bl and .CON. The .CON files for each cast contain the calibration coefficients for the instrument. The .HDR files contain the information in the header of each cast file. The .hex files are the data files for each cast and are in hex format. The .bl files contain CTD scans that were collected while the water bottle was being closed.

Data were processed following established BODC procedures and the following SeaBird routines were carried out: DATCNV, BOTTLESUM, WILDEDIT, FILTER, ALIGNCTD, CELLTM, LOOPEDIT, DERIVE and BINAVERAGE. The default settings were used in all of the routines except where specified below.

Field calibrations

Calibration of the oxygen sensor

Oxygen data was calibrated against discrete sample data processed by NOCS. A persistent offset was found between the CTD profile data and the calibration sample data, equivalent to a 4.15% positive error. CTD oxygen concentration data were therefore increased by 4.15% after comparison with the discrete sample Winkler titration measurements.

Salinity calibration

The salinity channel displayed some inaccuracies when compared with discrete sample data, however no adjustments were applied to the CTD salinity data. No corrections were deemed possible due to the low level of error in the calibration and uncertainties in local conditions.

BODC Reformatting

The data were delivered to BODC in separate files for the down and up casts with the downcast providing the best quality data due to collection in a continuous profile.

The data were converted from Sea-Bird ASCII format into BODC internal format using BODC transfer function 357. The following table shows how the variables within the Sea-Bird files were mapped to appropriate BODC parameter codes. Oxygen saturation, sigma-theta and potential temperature channels were derived during the transfer.

Originator's Parameter Name Originator's Units Description BODC Parameter Code BODC Units Comments
prDM: Pressure, Digiquartz dbar Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level PRESPR01 Decibars -
t090C: Temperature [ITS-90] °C Temperature of the water body by CTD or STD TEMPST01 Degrees Celsius -
t190C: Temperature, 2 [ITS-90] °C Temperature of the water body by CTD or STD TEMPST02 Degrees Celsius -
c0S/m: Conductivity Sm -1 Electrical conductivity of the water body by CTD CNDCST01 Siemens per metre -
c1S/m: Conductivity, 2 Sm -1 Electrical conductivity of the water body by CTD CNDCST02 Siemens per metre -
sbeox0V: Oxygen raw, SBE 43 volts Instrument output (voltage) by in-situ oxygen microelectrode OXYVLTN1 volts -
bat: Beam Attenuation, Chelsea/Seatech m -1 Attenuance (red light wavelength) per unit length of the water body by 20 or 25cm path length transmissometer ATTNDR01 per metre -
xmiss: Beam Transmission, Chelsea/Seatech % Transmittance (red light wavelength) per 25cm of the water body by 25cm path length red light transmissometer POPTDR01 Percent Manufacturer's calibration applied during processing
flC: Fluorescence, Chelsea Aqua 3 Chl Con ug l -1 Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate phase] by in-situ chlorophyll fluorometer and manufacturer's calibration applied CPHLPM01 Milligrams per cubic metre Manufacturer's calibration applied during processing
par: PAR/Irradiance, Biospherical/Licor Wm -2 Downwelling 2-pi scalar irradiance as energy (PAR wavelengths) in the water body by 2-pi scalar radiometer DWIRPP01 Watts per square metre -
par1: PAR/Irradiance, Biospherical/Licor, 2 Wm -2 Upwelling 2-pi scalar irradiance as energy (PAR wavelengths) in the water body by 2-pi scalar radiometer UWIRPP01 Watts per square metre -
turbWETbb0: Turbidity, WET Labs ECO BB m -1 Sr -1 Attenuance due to backscatter (660 nm wavelength at 117 degree incidence) by the water body [particulate phase] by in-situ optical backscatter measurement BB117R01 per metre per steradian -
sal00: Salinity, Practical PSU Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm PSALST01 Dimensionless -
sal11: Salinity, Practical, 2 PSU Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm PSALST02 Dimensionless -
sbeox0ML/L: Oxygen, SBE 43, WS = 2 ml/l Concentration of oxygen {O2} per unit volume of the water body [dissolved phase] by Sea-Bird SBE 43 sensor and calibration against sample data DOXYSC01 Micromoles per litre Converted from ml/l to µmol/l during transfer
sbeox0PS: Oxygen, SBE 43 saturation, WS = 2 % saturation Saturation of oxygen {O2} in the water body [dissolved phase] by Sea-Bird SBE 43 sensor and calibration against sample data and computation from concentration using Benson and Krause algorithm OXYSSC01 % Channel dropped after transfer
v3: Voltage 3 volts Chelsea MKIII Aquatracka fluorometer voltage FVLTPELN V -
v4: Voltage 4 volts Downwelling PAR sensor voltage LVLTPD01 V -
v5: Voltage 5 volts Upwelling PAR sensor voltage LVLTPU01 V -
v6: Voltage 6 volts Light Back-Scattering Sensor voltage NVLTWR01 V -
v7: Voltage 7 volts Transmissometer voltage TVLTDR01 V -
density00: Density kg m -3 - - - Channel not transferred
density11: Density, 2 kg m -3 - - - Channel not transferred
sigma-e00: Density [sigma-theta] kg m -3 - - - Channel not transferred
sigma-e11: Density, 2 [sigma-theta] kg m -3 - - - Channel not transferred
depSM: Depth [salt water] m - - - Channel not transferred
svCM: Sound Velocity [Chen-Millero] m s -1 - - - Channel not transferred
svCM1: Sound Velocity, 2 [Chen-Millero] m s -1 - - - Channel not transferred
name 0 = timeS: Time, Elapsed seconds - - - Channel not transferred
- - Oxygen saturation OXYSSC01 % Generated by BODC using the Benson and Krause (1984) algorithm with parameters DOXYSC01, PSALST01 and TEMPST01.
- - Sigma-theta, primary SIGTPR01 kg m -3 Generated by BODC using the Fofonoff and Millard (1982) algorithm from frame mounted sensors
- - Potential temperature, primary POTMCV01 °C Generated by BODC using the Fofonoff and Millard (1982) algorithm from frame mounted sensors
- - Sigma-theta, secondary SIGTPR02 kg m -3 Generated by BODC using the Fofonoff and Millard (1982) algorithm from frame mounted sensors
- - Potential temperature, secondary POTMCV02 °C Generated by BODC using the Fofonoff and Millard (1982) algorithm from frame mounted sensors

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), p. 620-632.

Fofonoff, NP and Millard, RC. 1983. Algorithms for computations of fundamental properties of seawater. UNESCO Technical Papers in Marine Science, 44, p.53.

UNESCO. 1981. Background papers and supporting data on the International Equation of State of Seawater 1980. UNESCO Technical Papers in Marine Science No. 38, p.192

Screening

Reformatted CTD data were visualized using the in-house graphical editor EDSERPLO. No data values were edited or deleted. All spurious and null data were flagged with BODC quality control flags.

PAR

Comparison between the voltage values and PAR values provided in the files with the calibration certificates showed that the data were out by a factor of 10 for the PAR values derived from voltages. This is a recurring problem with the way coefficients are entered into the Sea-Bird .CON files onboard the ship. A correction factor of x10 was applied to the DWIRPP01 and UWIRPP01 channels.

PAR sensors were not present on three casts (cast 30, 60 and 61) as these were deep casts to greater pressure than the sensors are rated to go. Cast 61 appears to have followed straight after 60 and there may not have been time during the turnaround to re-attach the PAR sensors.

Banking

Once quality control screening was complete, the CTD downcasts were banked. The primary salinity, temperature, density and potential temperature channels were retained as the best quality data channels from the two sensors.


Project Information

UKOARP Theme B: Ocean acidification impacts on sea surface biology, biogeochemistry and climate

The overall aim of this theme is to obtain a quantitative understanding of the impact of ocean acidification (OA) on the surface ocean biology and ecosystem and on the role of the surface ocean within the overall Earth System.

The aims of the theme are:

The main consortium activities will consist of in-situ measurements on three dedicated cruises, as well as on-deck bioassay experiments probing the response of the in-situ community to elevated CO2. Most of the planned work will be carried out on the three cruises to locations with strong gradients in seawater carbon chemistry and pH; the Arctic Ocean, around the British Isles and the Southern Ocean.

Weblink: http://www.oceanacidification.org.uk/research_programme/surface_ocean.aspx


Data Activity or Cruise Information

Cruise

Cruise Name D366 (D367)
Departure Date 2011-06-06
Arrival Date 2011-07-09
Principal Scientist(s)Eric Pieter Achterberg (University of Southampton School of Ocean and Earth Science)
Ship RRS Discovery

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