Metadata Report for BODC Series Reference Number 1749271
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
UK Ocean Acidification RRS Discovery Cruise D366 Underway Surface Hydrography Data Quality Report
Salinity, conductivity and temperature
No extensive flagging was required. The values fit within the range for the regions the cruise track passed through, for the time of year of the cruise.
Attenuance and transmittance
The transmissometer voltage declines in the second half of the cruise, then jumps back up before declining again. This coincides with the time around the Skaggerak with the low salinity waters. The sudden jumps in the transmissometer and fluorometer time series are due to the cleaning of the instrument on station according to the NMF report. The data have been flagged during periods when the transmissometer and Fluorometer were cleaned. This occured at the following times: 09/06/2014 1337-1347; 15/06/2014 0900-0910 and 30/06/2014 0834-0844. Intermittent flags were applied to obvious spikes in the transmissometer voltage channel. Where the transmittance voltage was 0 (close to the dark voltage output) which occurred during cleaning of the sensor, these were flagged Null instead of suspect in order to apply the manufacturers calibration correctly.
Fluorescence
The voltage was flagged sparingly as it shows natural variation. Cleaning of the instrument occurred at the same times as for the transmissometer, and data were flagged during these periods.
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.
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.
UK Ocean Acidification RRS Discovery Cruise D366 Underway Surface Hydrography Instrumentation
The instruments used to collect the surface hydrography datasets are displayed in the table below.
| Sensor | Serial number | Calibration date |
| Sea-Bird SBE38 | 0490 | 04/10/2010 |
| Sea-Bird SBE45 | 0230 | 16/07/2010 |
| Seatech C-star | CST-1132PR | 04/06/2010 |
| Wetlabs WetStar | WS3S-248 | 15/12/2010 |
UK Ocean Acidification RRS Discovery Cruise D366 Underway Surface Hydrography Data Processing Document
Originator's Data Processing
During the cruise there was a dual logging system in place on the RRS Discovery. Data from the various instruments were logged to the RVS Level-C system and also as NetCDF (binary) through the Ifremer Techsas data logging system.
Files delivered to BODC
| Filename | Data type | Start Calendar Day | Start Time | Finish Calendar Day | Finish Time | Interval |
| seabird | RVS Level-C raw | 2011-06-06 | 08:08:48 | 2011-07-09 | 12:55:52 | 1 sec |
| surfmet | RVS Level-C raw | 2011-06-06 | 08:08:47 | 2011-07-09 | 12:55:53 | 1 sec |
BODC Data Processing
Reformatting
The RVS files were transferred into internal BODC format by merging the files into a single binary file using time as the primary linking key. The time span of the file was from 06/06/2011 08:08:50 to 09/07/2011 12:55:50, with a sampling interval of 60 seconds.
The surface hydrography data were transferred to BODC format from the surfmet and seabird data files.
The originator's variables were mapped to appropriate BODC parameter codes as follows:
surfmet
| Channels | Description | Units | BODC Parameter Code | Units | Conversion Factor |
| temp_h | TSG housing temperature | - | not for transfer - loaded from seabird file with salinity | - | - |
| temp_m | Remote temperature at non-toxic inlet | - | not for transfer - loaded from seabird file with salinity | - | - |
| cond | TSG conductivity | - | not for transfer - loaded from seabird file with salinity | - | - |
| fluo | Raw fluorometer voltage | V | FVLTWS01 | V | *1 |
| trans | Raw transmissometer voltage | V | TVLTDR01 - channel not transferred | V | *1 |
seabird
| Channels | Description | Units | BODC Parameter Code | Units | Conversion Factor |
| temp_h | TSG housing temperature | Degrees Celsius | TMESSG01 - channel not transferred | Degrees Celsius | *1 |
| cond | TSG conductivity | S m-1 | CNDCSG01 - channel not transferred | S m-1 | *1 |
| salin | Salinity | PSU | PSALSU01 - uncalibrated | dimensionless | *1 |
| sndspeed | Velocity of sound in water | m s-1 | SVELSG01 - channel not transferred | m s-1 | *1 |
| temp_r | Remote temperature at non-toxic inlet | Degrees Celsius | TEMPHU01 - uncalibrated | Degrees Celsius | *1 |
Screening
Each data channel was inspected on a graphics workstation and any spikes or periods of dubious data were flagged. The power of the workstation software was used to carry out comparative screening checks between channels by overlaying data channels. A map of the cruise track was simultaneously displayed in order to take account of the oceanographic context.
Manufacturer's Calibratons
Transmissometer
The table below shows the Manufactuers calibration applied to the transmissometer voltage channel.
| Channel | Manufactuers Calibration equation | Coefficient Values |
| Transmittance (POPTDR01) | Light transmission (%) = 100 x (TVLTDR01 - Vdark) / (Vref - Vdark) | Vdark = 0.059 V, Vref = 4.685 V |
| Attenuance (ATTNDR01) | Attenuance (m-1 ) = (-1/path length) x ln(decimal transmittance) | path length = 0.25 m, decimal transmittance (Tr) = light transmission (%) / 100. |
Fluorometer
| Channel | Manufactuers Calibration equation | Coefficient Values |
| Fluorescence (CPHLUMTF) | Chl. a (µg l-3 ) = Scale Factor x (FVLTWS01 - Clean Water Offset) | Scale Factor = 15.1 µg l -1 V-1 , Clean Water Offset = 0.065 V |
Sample Calibrations
Temperature
The hull temperature sensor data were calibrated against the CTD temperature sensors during the cruise. The data from the hull sensor at the CTD start time were compared with the temperature from the externally mounted CTD temperature at 5 decibars. The temperature offsets (CTD - Hull) were plotted against date/time and CTD sensor temperature and 19 outliers were identified. The relationships in the offset between sensors were then compared to the date/time and the CTD sensor temperature in separate linear regressions. There was not a significant linear dependence between CTD temperature sample value and residual so the mean offset was applied. (R2 = 0.0028; n = 56; F = 0.6993; p = 0.89088 (intercept) and p = 0.6993(slope).
Applying the mean offset between the externally mounted CTD temperature sensor and the hull mounted temperature sensor, the calibrated temperature channel data were generated.
| Channel | Calibration equation |
| Hull Temperature | TEMPHG01 = TEMPHU01 - 0.01591 |
Salinity
The SBE45 salinity data were calibrated against bench salinometer data from samples collected from the underway system during the cruise. The data from the SBE45 TSG at the discrete sampling times were compared with the bench salinometer measurements. The salinity offsets (bench - TSG) were plotted against date/time and bench salinity then 17 outliers were identified. The relationships in the offset between TSG and bench salinometer were then compared to bench salinity using a linear regression. Two distinct regions were identified and separate calibrations were applied to both. For calibration 1, the regression of offset against bench salinity was not significant (R2 = 0.0025; n = 48; F = 0.7354; p = 0.701 (intercept) and p =0.735(slope). The regression of offset against linear time was also insignificant, so the mean offset was applied to data from the start of the file till 19/06/2011 16:11.
For calibration 2, the regression of offset against bench salinity was not significant (R2 = 0.0333; n = 57; F = 0.174; p = 0.100 (intercept) and p =0.174(slope). The regression of offset against linear time was significant, so the linear calibration was applied to data from 19/06/2011 16:11 to 09/07/2011 07:25.
Applying the equations from the bench salinometer regressions, the calibrated salinity channel data were generated using the BODC BUDS calibration routine.
| Channel | Calibration equation | Calibration time frame |
| Salinity calibration 1 | PSALSG01 = PSALSU01 - 0.0049 | 06/06/2011 07:58 to 19/06/2011 16:11 |
| Salinity calibration 2 | offset at start = -0.0049; offset at end = 0.0443 | 19/06/2011 16:11 to 09/07/2011 07:25 |
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:
- To ascertain the impact of OA on planktonic organisms (in terms of physiological impacts, morphology, population abundances and community composition).
- To quantify the impacts of OA on biogeochemical processes affecting the ocean carbon cycle (both directly and indirectly, such as via availability of bio-limiting nutrients).
- To quantify the impacts of OA on the air-sea flux of climate active gases (DMS and N2O in particular).
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 |
| B | nominal value |
| Q | value below limit of quantification |
