Metadata Report for BODC Series Reference Number 1964988
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
ATTNDR01
The Transmittance channel is very poor and the entire dataset has been flagged. Despite the sensor being cleaned regularly, large amounts of arbitrary decline is observed throughout the dataset. The signal would correct after cleaning and decrease exponentially with time. This is most likely due to trapped bubbles. In addition, there are noisy periods observed at points throughout the dataset. Spiking from when the non-toxic supply has been switched off for cleaning and spiking from sensor malfunction were also flagged.
POPTDR01
The Transmittance channel is very poor and the entire dataset has been flagged. Despite the sensor being cleaned regularly, large amounts of arbitrary decline is observed throughout the dataset. The signal would correct after cleaning and decrease exponentially with time. This is most likely due to trapped bubbles. In addition, there are noisy periods observed at points throughout the dataset. Spiking from when the non-toxic supply has been switched off for cleaning and spiking from sensor malfunction were also flagged.
TVLTDR01
The Transmittance channel is very poor and the entire dataset has been flagged. Despite the sensor being cleaned regularly, large amounts of arbitrary decline is observed throughout the dataset. The signal would correct after cleaning and decrease exponentially with time. This is most likely due to trapped bubbles. In addition, there are noisy periods observed at points throughout the dataset. Spiking from when the non-toxic supply has been switched off for cleaning and spiking from sensor malfunction were also flagged.
RRS Discovery DY090 Surface Hydrography Quality Control Report
Fluorescence
Other than when the non-toxic supply has been switched off for cleaning and the sensor malfunctions, the fluorometer data appears to be good.
SST and housing temperature, conductivity and salinity
The housing temperature readings are slightly (~0.5°C) warmer than the remote temperature values and features a 5 minute delay. To account for the time delay, the remote temperature channel was flagged to account for this time difference.
Salinity and conductivity channels look good and were flagged when the channel was getting cleaned and when obvious anomalous data was present as a result of sensor malfunctions.
RRS Discovery Surface Hydrography Quality Control Report
Sea Surface Temperature
The remote underway sea surface temperature data readings have been found to display a consistent variable offset when compared to CTD temperature readings at the same depth. As this is a general occurance, the remote underway temperature data should be used with caution if they have not been calibrated against in situ CTD temperature values.
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
RRS Discovery Cruise DY090 Underway Document
Cruise Details
| Cruise Details | 23rd May 2018 - 28th June 2018 (UTC) |
| Principal Scientific Officer | Dr. Stephanie Henson (National Oceanography Centre, Southampton) |
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 Discovery DY090 Surface Hydrography Instrumentation
Instrumentation
The sea surface hydrographical suite of sensors was fed by the pumped-seawater, non-toxic supply. The depth of the seawater intake was at 5.5 m.
The following surface hydrology sensors were fitted:
| Manufacturer | Model | Serial number | Last manufacturer's calibration date | Comments |
| WETLabs WS3S Fluorimeter | WS3S | WS3S-117 | 21/02/2018 | |
| Surf Trans: Wetlabs CST | Wetlabs CST | CST-1132PR | 12/12/2016 | |
| Sea-Bird SBE38 Temperature | SBE38 | 3854115-0490 | 07/07/2017 | |
| Sea-Bird | SBE45 TSG | 4548881-0230 | 05/01/2017 |
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 Discovery DY090 Surface Hydrography Data Processing Procedures
Originator's Data Processing
The data were logged by the TECHSAS (TECHnical and Scientific sensors Acquisition System) 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 |
| yyyymmdd-000000-Surf-DY-SM_DY1.SURFMETv2 | Fluorescence and transmittance | NetCDF | 1 sec. | 21-May-2018 13:11:12 | 27-Jun-2018 11:57:22 | |
| yyyymmdd-000000-SBE45-SBE45_DY1.TSG | Housing Temperature, remote temperature, salinity and conductivity | NetCDF | 1 sec. | 21-May-2018 13:11:12 | 27-Jun-2018 11:57:22 |
BODC Data Processing
The files were reformatted to BODC internal format using standard data banking procedures. All files were averaged to 60 second intervals. The following table shows how the variables within the files were mapped to appropriate BODC parameter codes:
yyyymmdd-000000-Surf-DY-SM_DY1.SURFMETv2
| Originator's variable | Originator's units | Description | BODC Code | BODC Units | Unit conversion | Comments |
| trans | volts | Raw voltage measured by transmissometer | TVLTDR01 | volts | none | |
| fluo | volt | Raw voltage measured by fluorometer | FVLTWS01 | volt | none | |
| temp_h | degrees celcius | Housing water temperature | Not transferred | |||
| 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-000000-SBE45-SBE45_DY1.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 | |
| 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 | |||
| sndspeed | m/s | TSG sound velocity | 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 field calibrations have been applied.
Manufacturers Calibrations
Transmissometer
The transmissometer voltage channel was converted to beam transmission ( beamtrans ) and beam attenuation ( atten ) as follows:
beamtrans [%] = ([ volts - Vdark ] / [ Vref - Vdark ])100
atten [per m] = (-1/ pathlength ) ln( beamtrans /100)
where Vdark = 0.058 V, Vref = 4.650 V and pathlength = 0.25 m.
Fluorometer
The fluorescence voltage channel was converted to engineering units ( chla ) using the following calibration:
chla [µg/L]= SF ( volts - CWO )
where SF = 5.1 µg/L/V and CWO = 0.070 V.
Project Information
Controls over Ocean Mesopelagic Interior Carbon Storage: COMICS
COMICS is a four-year collaborative research project that aims to quantify the flow of carbon in the ocean?s ?twilight? zone in order to accurately model global climate change. This ?twilight? zone is the part of the ocean between 100m and 1000m below the sea surface, where only a small amount of light from the sun can still penetrate.
By investigating carbon dynamics in the ocean interior, COMICS will help to improve predictions of future global climate change.
The COMICS project is led by the National Oceanography Centre and is a collaboration between the British Antarctic Survey and the universities of Queen Mary London, Liverpool, Oxford and Southampton. The project received funding from the Natural Environmental Research Council and runs between April 2017 and 2021.
Data Activity or Cruise Information
Cruise
| Cruise Name | DY090 |
| Departure Date | 2018-05-23 |
| Arrival Date | 2018-06-28 |
| Principal Scientist(s) | Stephanie Henson (National Oceanography Centre, Southampton) |
| 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 |
| B | nominal value |
| Q | value below limit of quantification |
