Metadata Report for BODC Series Reference Number 1760580
Metadata Summary
Problem Reports
Data Access Policy
Narrative Documents
Project Information
Data Activity or Cruise Information
Fixed Station Information
BODC Quality Flags
SeaDataNet Quality Flags
Metadata Summary
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Problem Reports
Raw transmittance, transmission and beam attenuationThese channels should be used with caution and the data considereed to be unrealistic from 15/01/2016 12:24 onwards when an issue with the instrument seems to have occurred, possibly a blockage in the system. The channel is drifting and cannot be relied on. All anomalous data have been flagged.
Fluorescence and chlorophyllThese channels should be used with caution and the data considereed to be unrealistic from 15/01/2016 12:24 onwards when an issue with the instrument seems to have occurred, possibly a blockage in the system. The channel is drifting and cannot be relied on. All anomalous data have been flagged.
RRS James Cook cruise JC132 Surface Hydrography Quality Report
Quality control report
General comments
The non-toxic, pumped seawater supply was switched on at 09:53:34 on 15/01/2016 at the start of the cruise, and was turned off at 22:08:00 on 22/02/2016, towards the end of the cruise; all housing measurements recorded outside this time span were flagged.
The underway system was switched off for cleaning on several occasions throughout the cruise. BODC flagged the affected housing parameters during the periods shown in the table below.
| Start | End |
| 21/01/2016 12:23:56 | 21/01/2016 12:49:54 |
| 08/02/2016 22:23:25 | 08/02/2016 22:32:20 |
| 16/02/2016 17:33:06 | 16/02/2016 17:58:19 |
Fluorescence and chlorophyll
The average chlorophyll and fluorescence measurements show an increase prior to the cleaning events which indicates evidence of an issue with the sensor readings. Following the reported cleaning of the underway pumped system, values drop back to the lower previous values.
Raw transmittance, transmission and beam attenuation
There is a drift in attenuance and transmittance data where values drop, on two occasions, prior to the time at which the underway system was switched off for cleaning events on the 08/02/2016 and 16/02/2016. Transmittance values return to previous values after cleaning.
Housing temperature, conductivity and salinity
TSG parameters occasionally seem to drift to adjustment levels for a short time after the underway system had been switched back on after cleaning; these instances were flagged. Occassional unrealistic spikes in TSG parameters have also been flagged.
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
SeaBird Digital Oceanographic Thermometer SBE38
The SBE38 is an ultra-stable thermistor that can be integrated as a remote temperature sensor with an SBE21 Thermosalinograph or an SBE 45 Micro TSG, or as a secondary temperature sensor with an SBE 16 plus, 16plus-IM, 16plus V2, 16plus-IM V2 or 19plus V2 SEACAT CTD.
Temperature is determined by applying an AC excitation to reference resistances and an ultra-stable aged thermistor. The reference resistor is a hermetically sealed VISHAY. AC excitation and ratiometric comparison using a common processing channel removes measurement errors due to parasitic thermocouples, offset voltages, leakage currents and gain errors.
The SBE38 can operate in polled sampling, where it takes one sample and transmits the data, or in continuous sampling.
Specifications
| Depth rating | up to 10500 m |
| Temperature range | -5 to 35°C |
| Initial accuracy | ± 0.001°C |
| Resolution | 0.00025°C |
| Stability | 0.001°C in 6 months |
| Response time | 500 ms |
| Self-heating error | < 200 µK |
Further details can be found in the manufacturer's specification sheet.
WET Labs WETStar Fluorometers
WET Labs WETStar fluorometers are miniature flow-through fluorometers, designed to measure relative concentrations of chlorophyll, CDOM, uranine, rhodamineWT dye, or phycoerythrin pigment in a sample of water. The sample is pumped through a quartz tube, and excited by a light source tuned to the fluorescence characteristics of the object substance. A photodiode detector measures the portion of the excitation energy that is emitted as fluorescence.
Specifications
By model:
| Chlorophyll WETStar | CDOM WETStar | Uranine WETStar | Rhodamine WETStar | Phycoerythrin WETStar | |
|---|---|---|---|---|---|
| Excitation wavelength | 460 nm | 370 nm | 485 nm | 470 nm | 525 nm |
| Emission wavelength | 695 nm | 460 nm | 530 nm | 590 nm | 575 nm |
| Sensitivity | 0.03 µg l-1 | 0.100 ppb QSD | 1 µg l-1 | - | - |
| Range | 0.03-75 µg l-1 | 0-100 ppb; 0-250 ppb | 0-4000 µg l-1 | - | - |
All models:
| Temperature range | 0-30°C |
|---|---|
| Depth rating | 600 m |
| Response time | 0.17 s analogue; 0.125 s digital |
| Output | 0-5 VDC analogue; 0-4095 counts digital |
Further details can be found in the manufacturer's specification sheet, and in the instrument manual.
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 Cook cruise JC132 Surface Hydrography Instrumentation
Instrumentation
The sea surface hydrographical suite of sensors was fed by the pumped-seawater, non-toxic supply. The seawater intake was located at 5.5 m below the sea surface.
The following surface hydrology sensors were fitted:
| Manufacturer | Model | Serial number | Last manufacturer's calibration date | Comments |
| WETLabs Fluorimeter | WETStar | WS3S-134 | 19/05/2015 | |
| WETLabs Transmissometer | C-Star | CST-114R | 26/09/2014 | 25 cm pathlength, 660 nm |
| Sea-Bird Temperature sensor | SBE38 | 386825-0689 | 24/06/2015 | |
| Sea-Bird | SBE45 TSG | 4548881-0230 | 11/09/2015 |
SeaBird MicroTSG Thermosalinograph SBE 45
The SBE45 MicroTSG is an externally powered instrument designed for shipboard measurement of temperature and conductivity of pumped near-surface water samples. The instrument can also compute salinity and sound velocity internally.
The MicroTSG comprises a platinum-electrode glass conductivity cell and a stable, pressure-protected thermistor temperature sensor. It also contains an RS-232 port for appending the output of a remote temperature sensor, allowing for direct measurement of sea surface temperature.
The instrument can operate in Polled, Autonomous and Serial Line Sync sampling modes:
- Polled sampling: the instrument takes one sample on command
- Autonomous sampling: the instrument samples at preprogrammed intervals and does not enter quiescence (sleep) state between samples
- Serial Line Sync: a pulse on the serial line causes the instrument to wake up, sample and re-enter quiescent state automatically
Specifications
| Conductivity | Temperature | Salinity | |
|---|---|---|---|
| Range | 0 to 7 Sm-1 | -5 to 35°C | |
| Initial accuracy | 0.0003 Sm-1 | 0.002°C | 0.005 (typical) |
| Resolution | 0.00001 Sm-1 | 0.0001°C | 0.0002 (typical) |
| Typical stability (per month) | 0.0003 Sm-1 | 0.0002°C | 0.003 (typical) |
Further details can be found in the manufacturer's specification sheet.
RRS James Cook cruise JC132 Surface Hydrography Processing Procedures
Data processing procedures
Originator's Data Processing
The data were logged by the TECHSAS (TECHnical and Scientific sensors Acquisition System) version 5.9 data logging system into daily NetCDF files which were provided to BODC for processing. Data was additionally logged into the RVS Level-C format which have been archived at BODC.
Files delivered to BODC
| Filename | Content description | Format | Interval | Start date/time (UTC) | End date/time (UTC) | Comments |
| 20160113-104201-Surf-JC-SM_JC1.SURFMETv2 | Fluorescence and transmittance | NetCDF | ~ 1 sec. | 13/01/2016 10:42:01 | 22/02/2016 22:12:27 | |
| 20160113-104201-SBE45-SBE45_JC1.TSG | Housing Temperature, remote temperature, salinity and conductivity | NetCDF | 1 sec. | 13/01/2016 10:42:01 | 22/02/2016 22:09:59 |
BODC Data Processing
The files were reformatted to BODC internal format using standard data banking procedures. All files were averaged to 30 second intervals. The following table shows how the variables within the files were mapped to appropriate BODC parameter codes:
yyyymmdd-104201-Surf-JC-SM_JC1.SURFMETv2
| Originator's variable | Originator's units | Description | BODC Code | BODC Units | Unit conversion | Comments |
| trans | volts | Raw voltage measured by transmissometer | TVLTZZ01 | volts | none | |
| temp_h | degrees celcius | Housing water temperature | Not transferred | |||
| fluo | volt | Raw voltage measured by fluorometer | FVLTWS01 | volt | none | |
| temp_m | degrees celcius | Remote temperature | Not transferred | |||
| cond | s/m | Conductivity | Not transferred | |||
| time | days since 1899-12-30 00:00:00 UTC | Acquisition time | Not transferred |
yyyymmdd-104201-SBE45-SBE45_JC1.TSG
| Originator's variable | Originator's units | Description | BODC Code | BODC Units | Unit conversion | Comments |
| salin | dimensionless | TSG salinity | PSALSU01 | dimensionless | none | |
| temp_h | degrees celcius | Housing water temperature | TMESSG01 | degrees celcius | none | |
| sndspeed | m/s | TSG sound velocity | Not transferred | |||
| cond | s/m | Conductivity | CNDCSG01 | s/m | none | |
| temp_r | degrees celcius | Remote water temperature | TEMPHU01 | degrees celcius | none | |
| time | days since 1899-12-30 00:00:00 UTC | Acquisition time | Not transferred |
All the reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag.
Calibration
Field Calibrations
No calibration against independent variables were applied to these data.
Manufacturers Calibrations
Transmissometer
The table below shows the Manufactuers calibration applied to the transmissometer voltage channel.
| Channel | Manufactuers Calibration equation | Coefficient Values |
| Transmittance | Light transmission (%) = 100 x (raw - Vdark) / (Vref - Vdark) | Vdark = 0.058 V, Vref = 4.685 V |
| Attenuance | Attenuance (m-1) = (-1/path length) x ln(decimal transmittance) | path length = 0.25 m, decimal transmittance (Tr) = light transmission (%) / 100. |
Fluorometer
The table below shows the Manufactuers calibration applied to the fluorometer voltage channel.
| Channel | Manufactuers Calibration equation | Coefficient Values |
| Fluorescence | Chl. a (µg l-3) = Scale Factor x (raw - Clean Water Offset) | Scale Factor = 13.1 µg l-1V-1, Clean Water Offset = 0.056 V |
Project Information
No Project Information held for the Series
Data Activity or Cruise Information
Cruise
| Cruise Name | JC132 |
| Departure Date | 2016-01-14 |
| Arrival Date | 2016-02-24 |
| Principal Scientist(s) | Christine Peirce (University of Durham, Department of Earth Sciences), Timothy Reston (University of Birmingham School of Geography, Earth and Environmental Sciences) |
| 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 |
