Metadata Report for BODC Series Reference Number 1839382
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
Data Description |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Data Identifiers |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Time Co-ordinates(UT) |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Spatial Co-ordinates | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Parameters |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Problem Reports
This channel should be used with caution. Data from the start of the cruise to around 21/10/2016 report unrealistic constant near-zero readings of around 0.03 to 0.05. All anomalous data have been flagged.
RRS James Clark Ross Cruise JR16001 (AMT26) Surface Hydrography Data Quality Document
Temperature, conductivity, salinity and sound velocity
Unrealistic values in the salinity, conductivity, temperature and sound velocity channels were flagged as improbable. There are several instances in the time series where the surface underway system was switched off. These instances can be identified by a sudden change in values of each parameter followed by sensor drift and then a switch back to previous values. These periods of data have been flagged. There is a drop in values present in all the above hydrography channels on 26/10/2016 from around 12:50 to 15:10. This time frame corresponds to the crossing of a possible front in the water column.
The second hull temperature sensor consistently recorded values of zero throughout the time series and therefore, the primary hull temperature sensor should be used in preference.
Beam transmission and attenuance
The transmittance and attenuance channels are noisy in places and spikes in the channels have been flagged to clean up the noise. There are several instances in the time series where the surface underway system was switched off. These instances can be identified by a sudden change in transmittance and attenuance values and have been flagged. There is a sudden change in the values at around 21/10/2016 13:44 following a cleaning event, after which values become more variable. Prior to this, the channel seems to arbitrarily decline, indicating possible trapped bubbles before cleaning. As it is unclear whether parts of this channel are improbable, the data have been left unflagged and BODC advise the user to use this channel with caution.
Fluorescence
The fluorescence channel was recording unrealistic values throughout the duration of the cruise. The whole channel has been flagged and should be considered as improbable due to the unreliable nature of the current fluorometer on the JCR.
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.
Turner Designs 10AU Field Fluorometer
The Turner Designs 10AU is designed for continuous-flow monitoring or discrete sample analyses of fluorescent species. A variety of optical kits with appropriate filters and lamps are available for a wide range of applications. Individual filters and lamps are also available for customised applications.
Standard optical kits include those for chlorophyll-a (extracted and/or in vivo), phycocyanin, phycoerythrin, CDOM, ammonium, rhodamine and fluorescein dye tracing, crude oil, refined oil, histamine and optical brighteners.
The instrument's light source is a 4 watt lamp and the detector is a photomultiplier tube with a standard detection range of 300-650 nm. A red-sensitive version with a detetion range of 185-970 nm is also available.
Specifications
| Operating temperature | 0 to 55°C |
| Detector | PhotoMultiplier Tube 300 to 650 nm (standard) 185 to 870 nm (Red) |
| Detection Limits: Extracted Chlorophyll-a Rhodamine WT Dye Fluorescein Dye | 0.025 µg L-1 0.01 ppb (in potable water) 0.01 ppb (in potable water) |
| Linear range: Extracted Chlorophyll-a Rhodamine WT Dye Fluorescein Dye | 0 to 250µg L-1 0 to 250 ppb 0 to 250 ppb |
Further details can be found in the manufacturer's specification sheet.
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.
Litre Meter flow meter
A flow meter used to monitor water flow rates for pumped systems such as ships' continuous seawater supplies.
RRS James Clark Ross Cruise JR16001 (AMT26) Surface Hydrography Instrument Description Document
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 | Main Function | Serial number | Last calibration date |
| Sea Bird Electronics | SBE45 | Thermosalinograph | 0016 | 14/05/2014 |
| Sea Bird Electronics | SBE38 | Temperature x2 sensors | 0601 and 0599 | 11/06/2015 |
| Chelsea Technologies | 10 AU-005 | Fluorometer | 1100243 | - |
| Wet Labs | C-Star | Transmissometer | CST-396DR | 06/08/2015 |
| Litremeter | 05SPFA40CE | Flow meter | 05/811950 | 09/06/2011 |
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 Clark Ross Cruise JR16001 (AMT26) Surface Hydrography Processing Procedures Document
Originator's Data Processing
The sea surface hydrography measurements were performed by a Sea Bird electronics thermosalinograph in the ship's flow through system and by a temperature sensor located near the flow through intake, at the hull. The depth of the flow through intake was 5.5 m. The data streams were logged every second to the SCS system and merged into a comma separated file format, and logged to the Oceanlogger.ACO file. The header information was stored in the associated .TPL files.
| Filename | Content Discription | Format | Interval | Start date | Start Time | End date | End Time |
| oceanlogger.ACO |
| ASCII (.ACO) | ~5 seconds | 19/9/2016 | 11:49:39 | 03/11/2016 | 15:33:50 |
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:
| Originator's File | Originator's Parameter | Originator's Units | Description | BODC code | BODC Units | Comments and unit conversions |
|---|---|---|---|---|---|---|
| oceanlogger.ACO | salinity | psu | Practical salinity of the water body by thermosalinograph and computation using UNESCO 1983 algorithm and NO calibration against independent measurements | PSALSU01 | Dimensionless | - |
| oceanlogger.ACO | sstemp | °C | Temperature of the water body by thermosalinograph hull sensor and NO verification against independent measurements | TEMPHU01 | °C | - |
| oceanlogger.ACO | sstemp2 | °C | Temperature of the water body by thermosalinograph hull sensor and NO verification against independent measurements sensor 2 | TEMPHU02 | °C | - |
| oceanlogger.ACO | tstemp | °C | Temperature of conductivity measurement by thermosalinograph | TMESSG01 | °C | - |
| oceanlogger.ACO | conductivity | S m-1 | Electrical conductivity of the water body by thermosalinograph | CNDCSG01 | S m-1 | - |
| oceanlogger.ACO | sound_velocity | m s-1 | Sound velocity in the water body by thermosalinograph and computation from temperature and salinity by unspecified algorithm | SVELSG01 | m s-1 | - |
| oceanlogger.ACO | chlorophyll | µg l-1 | Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate phase] by through-flow fluorometer plumbed into non-toxic supply and manufacturer's calibration applied | CPHLUMTF | mg m-3 | - |
| oceanlogger.ACO | flowrate | l min-1 | Flow rate through instrument | INFLTF01 | l min-1 | - |
| oceanlogger.ACO | trans | % | Transmittance | POPTDR01 | % | x 100 % |
Sample Calibrations
The ship's underway meteorological and surface systems were run continuously through the cruise. The sea surface hydrography system started logging from 20/09/2016 and was switched off for brief periods in Portsmouth Harbour (22/09/2016) and South Georgia (29/10/2016) then turned off approaching the Falklands, morning 03/11/2016. Samples were collected to calibrate the TSG and fluorometer connected to the ship's non-toxic flow-through system, which draws water from approximately 7 m below the water line.
Salinity
The TSG sensor salinity data were calibrated against samples collected and analysed with a bench salinometer. Up to five samples were collected each day. There was a weak but significant regression of the offset with bench salinity measurement (n = 135; r2 = 0.037897; p < 0.05). There was also a weak but significant regression of offset against time (n = 135; r2 = 0.3959; p < 0.05). Applying the regeression with time did not improve the dataset, and there was still a trend with discrete salinity, so the regression against discrete salinity was applied.
- PSALSG01 = 1.0037 * PSALSU01 - 0.1357
Hull Mounted Temperature Sensor
The hull temperature sensor was calibrated against the mean of the CTD temperature sensor values at each station. There was no significant regression of the offset with surface CTD sensor values (n = 46; r2 = 0.0665; p = 0.0837) but there was significant regression with time (n = 46; r 2 = 0.1532; p = 0.0071). The regression equation for the trend with time was applied.
TEMPHG01 = [a + (b*day)] + TEMPHU01
- Where a = intercept = 0.00698 and b = slope = -0.03587
The offsets with the newly adjusted values were re-calculated and regression analysis performed; there was now no relationship between offset and CTD temperature or offset against cruise day, so no further calibration was necessary.
Beam Attenuance
Beam transmittance was converted to beam attenuance using a standard conversion for a 25 cm pathlength transmissometer.
- ATTNDR01 = (-4.000000 * ln (POPTDR01 * 0.010000))
Project Information
No Project Information held for the Series
Data Activity or Cruise Information
Cruise
| Cruise Name | JR16001 (AMT26) |
| Departure Date | 2016-09-20 |
| Arrival Date | 2016-11-04 |
| Principal Scientist(s) | Andrew Rees (Plymouth Marine Laboratory) |
| Ship | RRS James Clark Ross |
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 |
