Metadata Report for BODC Series Reference Number 1817000
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
No Problem Report Found in the Database
RRS Discovery cruise DY072 surface hydrography quality control report
General comments
All sea surface hydrography data were considered suspect from the 29/03/2017 10:24:30 until the end of the cruise when the non-toxic supply appeared to be turned off. The data were flagged appropriately. (BODC assessment).
Thermosalinograph TSG (salinity, conductivity and housing temperature)
TSG sensors were considered suspect from the beginning of the cruise until the 04/03/2017 22:48:30 when the sensors appeared to be active. Since the fluorometer and transmissometer were already active, it is possible the TSG was faulty or not connected until this point. The data were flagged appropriately. (BODC assessment).
Sea surface temperature (SST)
The SST sensor was considered suspect from the beginning of the cruise until the 04/03/2017 22:48:30 when the sensor appeared to be active. Since the fluorometer and transmissometer were already active, it is possible the SST sensor was faulty or not connected until this point. The data were flagged appropriately. (BODC assessment).
Chlorophyll and fluorescence
The fluorometer appeared faulty from the 21/03/2017 15:28:30 until the end of the cruise. The data were flagged appropriately. (BODC assessment).
Transmissometer voltage, transmittance and attenuation
The transmissometer appeared faulty from the 21/03/2017 15:28:30 until the end of the cruise. The data were flagged appropriately. (BODC assessment).
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
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 cruise DY072 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 Fluorimeter | WETStar | WS3S-134 | 06/06/2016 | |
| WETLabs Transmissometer | C-Star | CST-1131R | 12/04/2016 | 25 cm pathlength, 660 nm |
| Sea-Bird Temperature sensor | SBE38 | 3854115-0489 | 28/08/2016 | |
| Sea-Bird | SBE45 TSG | 4548881-0233 | 28/07/2016 |
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 cruise DY072 surface hydrography 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 |
| yyyymmdd-090000-Surf-DY-SM_DY1.SURFMETv2 | Fluorescence and transmittance | NetCDF | ~ 1 sec. | 28/02/2017 16:20:34 | 30/03/2017 12:15:28 | |
| yyyymmdd-090000-SBE45-SBE45_DY1.TSG | Housing Temperature, remote temperature, salinity and conductivity | NetCDF | 1 sec. | 28/02/2017 16:20:34 | 30/03/2017 12:15:28 |
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-090000-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 | |
| 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-090000-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 | |
| 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 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 = 4.668 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 = 12.8 µg/L/V and CWO = 0.061 V.
Project Information
Passive Imaging of the Lithosphere Asthensphere Boundary (PiLAB)
PiLAB is a three-year collaborative research project that aims taims to systematically image the entire length of an oceanic plate, from its birth at the Mid-Atlantic Ridge, to its oldest formation on the African margin, in order to determine the processes and properties that define and strengthen a plate.
Through this, PiLAB will improve global understanding of plate physiology and structure.
The PiLAB project is led by the University of Southampton, school of Ocean and Earth Sciences and is a collaboration between IFM GEOMAR, Germany, the Institute of Earth Physics, IPGP, France, and the universities of California and Bristol. The project received funding from the Natural Environmental Research Council and runs between February 2016 and January 2019 and forms part of the UK contribution to the global GEOTRACES project.
Data Activity or Cruise Information
Cruise
| Cruise Name | DY072 |
| Departure Date | 2017-02-28 |
| Arrival Date | 2017-04-02 |
| Principal Scientist(s) | Catherine A Rychert (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 |
| B | nominal value |
| Q | value below limit of quantification |
