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Metadata Report for BODC Series Reference Number 1205631


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
NameCategories
Sea-Bird SBE 43 Dissolved Oxygen Sensor  dissolved gas sensors
Sea-Bird SBE 911plus CTD  CTD; water temperature sensor; salinity sensor
WETLabs ECO BB(RT)D Scattering Meter  optical backscatter 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 Alex Forryan
Originating Organization National Oceanography Centre, Southampton
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) OSMOSIS
 

Data Identifiers

Originator's Identifier CTD_JC090_001_2DB
BODC Series Reference 1205631
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2013-09-03 15:57
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval 2.0 decibars
 

Spatial Co-ordinates

Latitude 48.68030 N ( 48° 40.8' N )
Longitude 16.19080 W ( 16° 11.4' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth 2.98 m
Maximum Sensor or Sampling Depth 1001.02 m
Minimum Sensor or Sampling Height 3811.98 m
Maximum Sensor or Sampling Height 4810.02 m
Sea Floor Depth 4813.0 m
Sea Floor Depth Source CRREP
Sensor or Sampling Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor or Sampling Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
 

Parameters

BODC CODERankUnitsTitle
ACYCAA011DimensionlessSequence number
BB117R011per metre per nanometre per steradianAttenuation due to backscatter (660 nm wavelength at 117 degree incidence) by the water body [particulate >unknown phase] by in-situ optical backscatter measurement
CNDCST011Siemens per metreElectrical conductivity of the water body by CTD
CPHLPR011Milligrams per cubic metreConcentration of chlorophyll-a {chl-a CAS 479-61-8} per unit volume of the water body [particulate >unknown phase] by in-situ chlorophyll fluorometer
DOXYZZ011Micromoles per litreConcentration of oxygen {O2 CAS 7782-44-7} per unit volume of the water body [dissolved plus reactive particulate phase] by in-situ sensor
OXYSZZ011PercentSaturation of oxygen {O2 CAS 7782-44-7} in the water body [dissolved plus reactive particulate phase]
POPTDR011PercentTransmittance (red light wavelength) per 25cm of the water body by 25cm path length red light transmissometer
POTMCV011Degrees CelsiusPotential temperature of the water body by computation using UNESCO 1983 algorithm
PRESPR011DecibarsPressure (spatial coordinate) exerted by the water body by profiling pressure sensor and correction to read zero at sea level
PSALST011DimensionlessPractical salinity of the water body by CTD and computation using UNESCO 1983 algorithm
SIGTPR011Kilograms per cubic metreSigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm
TEMPST011Degrees CelsiusTemperature of the water body by CTD or STD
TOKGPR011Litres per kilogramConversion factor (volume to mass) for the water body by CTD and computation of density (in-situ potential temperature surface pressure) reciprocal from pressure, temperature and salinity

Definition of Rank

  • Rank 1 is a one-dimensional parameter
  • Rank 2 is a two-dimensional parameter
  • Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

Problem Reports

No Problem Report Found in the Database

Data quality report for JC090 CTD data

Oxygen super-saturation is present close to the surface. The user should use these data with caution.

On CTD casts 7, 8 and 9 there are negative chlorophyll values present. These have been flagged as suspect by BODC.


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.

JC090 CTD instrument description

CTD unit and auxiliary sensors

The CTD configuration comprised of a Sea-Bird 9plus underwater unit, #09P-54047-0943, with accompanying Sea-Bird 11plus deck unit, #11P-24680-0587. The CTD frame was fitted with two Sea-Bird 3 Premium temperature sensors, two Sea-Bird 4 conductivity sensors and a digiquartz temperature compensated pressure sensor.

Additional sensors fitted to the CTD frame include a Sea-Bird 43 dissolved oxygen sensor, Chelsea Technologies Group Alphatracka transmissometer, WETLabs turbidity sensor and a Benthos PSA-916T altimeter. For casts 2,4,5 and 6 two Chelsea Technologies Group 2-pi PAR irradiance sensors (upwelling and downwelling) were added.

All instruments were attached to a Sea-Bird 24 position carousel #32-31240-0423. These were 24 Ocean Test Equipment 20L water samplers (#1b-#24b), a TRDI WHM 300 kHz LADCP (#15288) and a NOCS LADCP battery pack (#WH005).

The table below lists more detailed information about the various sensors.

Sensor Unit Model Serial Number Full Specification Casts Last calibration date (YYYY-MM-DD) Comments
CTD underwater unit SBE 9plus 09P-54047-0943 SBE 9plus 1-9 - -
Temperature sensor SBE 3P 03P- 2919 SBE 03P 1-9 2013-02-15 Primary sensor
Temperature sensor SBE 3P 03P - 4151 SBE 03P 1-9 2013-02-15 Secondary sensor
Conductivity sensor SBE 4 04C-2841 SBE 04C 1-9 2012-07-27 Primary sensor
Conductivity sensor SBE 4 04C-3698 SBE 04C 1-9 2012-12-12 Secondary sensor
Pressure sensor SBE 9plus digiquartz 110557 - 1-9 2012-05-29 -
Dissolved Oxygen Sea-Bird 43 43-1882 SBE 43 1-9 2011-08-2 -
PAR/Irradiance Chelsea Technologies Group 2-pi PAR 007 2-pi PAR 2,4,5 and 6 2012-05-2 Downward facing sensor
PAR/Irradiance 1 Chelsea Technologies Group 2-pi PAR 002 2-pi PAR 2,4,5 and 6 2013-05-7 Upward facing sensor
Transmissometer Chelsea Technologies Group Alphatracka MKII 09-7107-001 Alphatracka MKII 1-9 2012-06-11 -
Fluorometer Chelsea Technologies Group AQUAtracka MKIII 088195 AQUAtracka MKIII 1-9 2012-08-21 -
Turbidity Meter WET Labs ECO-BBRTD 168 - 1-9 2012-09-24 -
Benthos altimeter PSA-916T 41302 - 1-9 2006-03-13 -

The discrete salinity samples collected from water bottles on the CTD were analysed in the ship's temperature-controlled room using a Guildline Autosal model 8400B salinometer (#60839). Dissolved oxygen concentrations from further water samples were determined using a titration technique.

References

Naveira-Garabato, A. C. et al. (2013). 'Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study (OSMOSIS)'. Cruise Report No. 25 National Oceanography Centre, Southampton.

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 ALPHAtracka (the Mark I) and its successor, the ALPHAtracka 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 ALPHAtracka and ALPHAtracka 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 ALPHAtrackaII 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:

  • ECO BB(RT)provides analog or RS-232 serial output with 4000 count range
  • ECO BB(RT)D adds the possibility of being deployed in depths up to 6000 m while keeping the capabilities of ECO BB(RT)
  • ECO BB provides the capabilities of ECO BB(RT) with periodic sampling
  • ECO BBB is similar to ECO BB but with internal batteries for autonomous operation
  • ECO BBS is similar to ECO BB but with an integrated anti-fouling bio-wiper
  • ECO BBSB has the capabilities of ECO BBS but with internal batteries for autonomous operation

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% R2
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.

BODC CTD Screening

BODC screen both the series header qualifying information and the parameter values in the data cycles themselves.

Header information is inspected for:

  • Irregularities such as infeasible values
  • Inconsistencies between related information. For example:
    • Deepest CTD data cycle is significantly greater than the depth of the sea floor.
    • Times of the cruise and the start/end of the data series.
    • Length of the record, number of data cycles, cycle interval, clock error and the period over which data were collected.
    • Parameters stated as measured and the parameters actually present in the data series.
  • Originator's comments on instrument/sampling device performance and data quality.

Documents are written by BODC highlighting irregularities that cannot be resolved.

Data cycles are inspected using depth series plots of all parameters. These presentations undergo screening to detect infeasible values within the data cycles themselves and inconsistencies when comparing adjacent data sets displaced with respect to depth, position or time.

Values suspected of being of non-oceanographic origin may be tagged with the BODC flag denoting suspect value.

The following types of irregularity, each relying on visual detection in the time series plot, are amongst those that may be flagged as suspect:

  • Spurious data at the start or end of the record where the instrument was recording in air
  • Obvious spikes occurring in the data due electrical problems
  • Constant, or near-constant, data channels

If a large percentage of the data is affected by irregularities, deemed abnormal, then instead of flagging the individual suspect values, a caution may be documented.

The following types of inconsistency are detected automatically by software:

  • Data points with values outside the expected range for the parameter, as defined by the BODC parameter usage vocabulary.

Inconsistencies between the characteristics of the data set and those of its neighbours are sought, and where necessary, documented. This covers inconsistencies in the following:

  • Maximum and minimum values of parameters (spikes excluded).
  • Anomalous readings due to the CTD package being bounced through temperature and/or salinity gradients.

This screening of the parameter values seeks to confirm the qualifying information and the source laboratory's comments on the series. In screening and collating information, every care is taken to ensure that errors of BODC's making are not introduced.

JC090 Originator's CTD data processing

The following information contains extracts from the JC090 cruise report.

Sampling strategy

The RRS James Cook 090 cruise was the concluding phase of the fieldwork for the Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study (OSMOSIS) consortium and sought to recover 9 moorings and 2 gliders, to conduct hydrographic and biogeochemical measurements for mooring and glider calibration, and to obtain opportunistic measurements of upper-ocean microstructure and air-sea CO2 fluxes.

The cruise departed on the 30 August 2013 from the port of Vigo, Spain and returned on the 17 September 2013 at the port of Santander, Spain.

A total of 9 CTD casts were deployed during the cruise with the deepest cast reaching 1000 m.

For casts 2, 4, 5 and 6 PAR sensors were added and for all other casts, the PAR sensors were removed. The primary purpose of these deployments were to calibrate nearby mooring and glider instrumentation.

The conductivity-temperature sensor is the first choice sensor for all casts. The CTDs were equipped with two conductivity sensors and two temperature sensors each. The primary conductivity-temperature sensor for each frame was attached near the bottom of the CTD frame and the secondary sensor attached to the fin. The primary and secondary sensors compared well during the cruise. Additional sensors on the CTD were dissolved oxygen, PAR, transmissometer, fluorometer, turbidity and an altimeter.

CTD wire 1 was used throughout, only once being terminated at the start of the cruise. In an attempt to prevent the wire from "un-wrapping", the wire was streamed once, prior to any CTD cast taking place, to 4,500 m. A 600 kg weight with a swivel attached was used as a weight on the wire.

Data Processing

Initial data processing was performed using the SeaBird processing software SBE Data Processing version 7.21b. The following steps were performed:

  • Data conversion - converts raw data to physical units.
  • Cell thermal mass - takes the .cnv files output from the data conversion and makes corrections for the thermal mass of the cell, in an attempt to minimize salinity spiking in steep vertical gradients.
  • Bottle summary - generates an ASCII summary .bl file of the bottle firing data from the cast .ros file.

The entire Mstar software suite is written in Matlab and uses a NetCDF file format to store all the data. The 5 CTD files store all the data from the CTD sensors. These are: raw, 24Hz, 1Hz, psal and 2db. The Mstar software program averages and interpolates the raw data until it has 2db resolution.

BODC will transfer the 2db resolution CTD data.

Field Calibrations

A total of 60 SBE37 SMP MicroCAT CTDs were used for comparison and field calibrations. This included 20 SBE37 SMP MicroCAT CTDs added to CTD casts 7, 8 and 9.

The oxygen sensor was calibrated against discrete samples taken from Niskin bottles on the CTD. A multiplicative correction factor for the CTD oxygen was estimated as the mean ratio of the bottle and CTD oxygen values. This factor was calculated using data from all the casts. Oxygen calibration was applied to the oxygen values in the CTD processing re-run.

Salinity derived from the primary conductivity-temperature sensors were calibrated against salinity derived from bottle samples at the same depths. A multiplicative correction factor for the CTD salinity was estimated as the mean ratio of bottle conductivity and CTD conductivity. Conductivities were further corrected using an additive factor calculated from a quadratic fit to bottle. Conductivity calibration was applied to the primary conductivity sensor in the CTD processing re-run.

References

Naveira-Garabato, A. C. et al. (2013). 'Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study (OSMOSIS)'. Cruise Report No. 25 National Oceanography Centre, Southampton.

Processing by BODC of RRS James Cook JC090 CTD data

The data arrived at BODC in 9 MSTAR format files representing the CTD casts conducted during cruise JC090, one file per cast. The data contained in the files are the downcast data averaged to a 2db pressure grid. The casts were reformatted to BODC's internal NetCDF format. The following table shows the mapping of variables within the MSTAR files to appropriate BODC parameter codes:

Originator's Variable Units Description BODC Parameter Code Units Comment
press dbar Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level PRESPR01 dbar -
temp °C Temperature of the water body by CTD or STD TEMPST01 °C ITS-90
temp1 °C - - - Not transferred
temp2 °C - - - Not transferred
cond mS cm-1 Electrical conductivity of the water body by CTD CNDCST01 S m-1 Unit conversion /10
cond1 mS cm-1 - - - Not transferred
cond2 mS cm-1 - - - Not transferred
psal - Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm PSALST01 - Calibrated by Data Originator using discrete water samples from CTD bottles.
psal1 - - - - Not transferred
psal2 - - - - Not transferred
oxygen µmol kg-1 Concentration of oxygen {O2} per unit volume of the water body [dissolved plus reactive particulate phase] by in-situ sensor DOXYZZ01 µmol l-1 Conversion from kg to litre. Calibrated by Data Originator using discrete water samples from CTD bottles.
fluor µg l-1 Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate >unknown phase] by in-situ chlorophyll fluorometer CPHLPR01 mg m-3 -
transmittance % Transmittance (red light wavelength) per 25cm of the water body by 25cm path length red light transmissometer POPTDR01 % -
turbidity m-1sr-1 Attenuance due to backscatter (470 nm wavelength at 117 degree incidence) by the water body [particulate phase] by in-situ optical backscatter measurement BB117R01 m-1nm-1sr-1 -
par µEinsteins m-2sec-1 Downwelling 2-pi scalar irradiance as energy (PAR wavelengths) in the water body by 2-pi scalar radiometer DWIRPP01 W m-2 Unit conversion *0.2174. Applies to casts 2,4,5 and 6.
par1 µEinsteins m-2sec-1 Upwelling 2-pi scalar irradiance as energy (PAR wavelengths) in the water body by 2-pi scalar radiometer UWIRPP01 W m-2 Unit conversion *0.2174. Applies to casts 2,4,5 and 6.
- - Potential temperature of the water body by computation using UNESCO 1983 algorithm POTMCV01 °C Derived during transfer.
- - Sigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm SIGTPR01 kg m-3 Derived during transfer.
- - Saturation of oxygen {O2} in the water body [dissolved plus reactive particulate phase] OXYSZZ01 % Derived during transfer.
- - 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 TOKGPR01 l kg-1 Derived during transfer.

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


Project Information

Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study (OSMOSIS)

Background

The Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study (OSMOSIS) consortium was funded to deliver NERC's Ocean Surface Boundary Layer (OSBL) programme. Commencing in 2011, this multiple year study will combine traditional observational techniques, such as moorings and CTDs, with the latest autonomous sampling technologies (including ocean gliders), capable of delivering near real-time scientific measurements through the water column.

The OSMOSIS consortium aims to improve understanding of the OSBL, the interface between the atmosphere and the deeper ocean. This layer of the water column is thought to play a pivotal role in global climate and the productivity of our oceans.

OSMOSIS involves collaborations between scientists at various universities (Reading, Oxford, Bangor, Southampton and East Anglia) together with researchers at the National Oceanography Centre (NOC), Scottish Association for Marine Science (SAMS) and Plymouth Marine Laboratory (PML). In addition, there are a number of project partners linked to the consortium.

Scientific Objectives

  • The primary goal of the fieldwork component of OSMOSIS is to obtain a year-long time series of the properties of the OSBL and its controlling 3D physical processes. This is achieved with an array of moorings (two nested clusters of 4 moorings, each centred around a central mooring) and gliders deployed near the Porcupine Abyssal Plain (PAP) observatory. Data obtained from this campaign will help with the understanding of these processes and subsequent development of associated parameterisations.
  • OSMOSIS will attempt to create parameterisations for the processes which determine the evolving stratification and potential vorticity budgets of the OSBL.
  • The overall legacy of OSMOSIS will be to develop new (physically based and observationally supported) parameterisations of processes that deepen and shoal the OSBL, and to implement and evaluate these parameterisations in a state-of-the-art global coupled climate model, facilitating improved weather and climate predictions.

Fieldwork

Three cruises are directly associated with the OSMOSIS consortium. Preliminary exploratory work in the Clyde Sea (September 2011) to hone techniques and strategies, followed by a mooring deployment and recovery cruise in the vicinity of the Porcupine Abyssal Plain (PAP) observatory (in late Summer 2012 and 2013 respectively). Additional opportunist ship time being factored in to support the ambitious glider operations associated with OSMOSIS.

Instrumentation

Types of instrumentation and measurements associated with the OSMOSIS observational campaign:

  • Ocean gliders
  • Wave rider buoys
  • Towed SeaSoar surveys
  • Microshear measurements
  • Moored current meters, conductivity-temperature sensors and ADCPs
  • Traditional shipboard measurements (including CTD, underway, discrete nutrients, LADCP, ADCP).

Contacts

Collaborator Organisation
Prof. Stephen Belcher University of Reading, U.K
Dr. Alberto C Naveira Garabato University of Southampton, U.K

Data Activity or Cruise Information

Cruise

Cruise Name JC090
Departure Date 2013-08-31
Arrival Date 2013-09-16
Principal Scientist(s)Alberto C Naveira Garabato (University of Southampton School of Ocean and Earth Science)
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
B nominal value
Q value below limit of quantification