Metadata Report for BODC Series Reference Number 1759806
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 D381A and D381B Surface Hydrography quality report
General comments
The non-toxic system was enabled as soon as we were far enough away from land. It is also used as a coolant for the seasoar winch system. The SBE45 unit fluorometer and transmissometer was cleaned prior to sailing. All underway water sampling instruments were checked daily, and cleaned periodically, while on station.
Fluorescence and chlorophyll
Spikes seen throughout the cruise have been flagged appropriately. (BODC assessment)
Feature observed between 25-27th September which coincides with bad weather. Probably suspect data. (BODC assessment)
Raw transmittance, transmission and beam attenuation
Spikes seen throughout the cruise have been flagged appropriately. (BODC assessment)
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 D381A and D381B 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 | 11/11/2011 | |
| WETLabs Transmissometer | C-Star | CST-112R | 11/10/2011 | 25 cm pathlength |
| Sea-Bird Temperature sensor | SBE38 | 0416 Remote Temp. | 27/06/2011 | |
| Sea-Bird | SBE45 TSG | 0231 TSG | 19/12/2011 |
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 Discovery D381A and D381B Surface Hydrography processing procedures
Originator's Data Processing
The following is adapted from the Discovery 381 cruise report.
Underway surface meteorology and thermosalinograph measurements were recorded by the RVS Surfmet system throughout Discovery cruise 381B.
Processing of the underway data was undertaken in the middle of the cruise to check the quality of the instruments conductivity and temperature measurement, through a check on salinity calibration, and then again at the end of the cruise. Processing entailed running a number of PSTAR routines as detailed below.
- surfmet0 : This script was used to convert the data from RVS format to PSTAR format using datapup. Resultant file was smt381**.raw
- surfmet1 : This ensured absent Surfmet data values were set to -999. The script also calculated TSG salinity using housing temperature, conductivity and a pressure value set to zero. Laboratory calibration of meteorological variables was applied also at this point. The Surfmet system applies the laboratory temperature sensor calibrations before the data reaches the RVS surfmet stream that we read in withsmtexec0.
- surfmet2 : The master Ashtech file and navigation file were merged with smt369** at this point. This allowed accurate heading data to be incorporated into the underway dataset. The data were also averaged to 2 minute values here. This step creates the file smt381**.hdg
- surfmet3 : This routine computed vessel speed and subtracted it from relative winds to obtain true wind speed and direction. Resultant file was smt381**.met
Salinity samples were taken from the underway source routinely approximately every hour during much of D381B, somewhat less frequently during D381A. A master Excel file of sample times and corresponding bottle salinities was read into PSTAR. The new file was then merged, using pmerge, with the existing smt381nn files to directly compare underway salinity (salin) and bottle salinity (botsal) in order to determine and apply a calibration to the underway salinity data. The initial comparisons were very good, suggesting zero offset in salinity. No calibration applied.
Files delivered to BODC
| Filename | Content description | Format | Interval | Start date/time (UTC) | End date/time (UTC) | Comments |
| smt381tot | Surfmet | Pstar | 2 min averaged | 24/08/2012 13:05:00 | 29/09/2012 09:01:00 | - |
BODC Data Processing
Data were banked at BODC following standard banking procedures. During reformatting the data were split into two files for the two legs of the cruises D381A and D381B.
The following table shows how the variables within the files were mapped to appropriate BODC parameter codes:
| Originator's variables | Originator's units | Description | BODC code | BODC units | Unit conversion | Comments |
| time | time from 1/1/2012 00:00:00 | acquisition time | Not transferred | |||
| dtime | dummy time channel | acquisition time | Not transferred. | |||
| temp_h | degrees celcius | TSG housing temperature | TMESSG01 | degrees celcius | ||
| temp_m | degrees celcius | Intake water temperature | TEMPHU01 | degrees celcius | ||
| cond | mmho cm-1 | TSG housing conductivity | CNDCSG01 | S m-1 | 1 mmho cm-1 = 1 S m-1 | |
| fluor | volts | Raw voltage from Fluorometer | FVLTWS01 | volts | ||
| trans | volts | Raw voltage from Transmissometer | TVLTDR01 | - | ||
| salin | psu | Salinity | PSALSU01 | dimensionless | Derived from from cond, temp_h and press |
Screening
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 = 0.060 V, Vref = 4.658 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 = 15.0 µg/L/V and CWO = 0.064 V.
Project Information
Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study (OSMOSIS)
Background
The Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study (OSMOSIS) consortium was funded to deliver NERC's Ocean Surface Boundary Layer (OSBL) programme. Commencing in 2011, this multiple year study will combine traditional observational techniques, such as moorings and CTDs, with the latest autonomous sampling technologies (including ocean gliders), capable of delivering near real-time scientific measurements through the water column.
The OSMOSIS consortium aims to improve understanding of the OSBL, the interface between the atmosphere and the deeper ocean. This layer of the water column is thought to play a pivotal role in global climate and the productivity of our oceans.
OSMOSIS involves collaborations between scientists at various universities (Reading, Oxford, Bangor, Southampton and East Anglia) together with researchers at the National Oceanography Centre (NOC), Scottish Association for Marine Science (SAMS) and Plymouth Marine Laboratory (PML). In addition, there are a number of project partners linked to the consortium.
Scientific Objectives
- The primary goal of the fieldwork component of OSMOSIS is to obtain a year-long time series of the properties of the OSBL and its controlling 3D physical processes. This is achieved with an array of moorings (two nested clusters of 4 moorings, each centred around a central mooring) and gliders deployed near the Porcupine Abyssal Plain (PAP) observatory. Data obtained from this campaign will help with the understanding of these processes and subsequent development of associated parameterisations.
- OSMOSIS will attempt to create parameterisations for the processes which determine the evolving stratification and potential vorticity budgets of the OSBL.
- The overall legacy of OSMOSIS will be to develop new (physically based and observationally supported) parameterisations of processes that deepen and shoal the OSBL, and to implement and evaluate these parameterisations in a state-of-the-art global coupled climate model, facilitating improved weather and climate predictions.
Fieldwork
Three cruises are directly associated with the OSMOSIS consortium. Preliminary exploratory work in the Clyde Sea (September 2011) to hone techniques and strategies, followed by a mooring deployment and recovery cruise in the vicinity of the Porcupine Abyssal Plain (PAP) observatory (in late Summer 2012 and 2013 respectively). Additional opportunist ship time being factored in to support the ambitious glider operations associated with OSMOSIS.
Instrumentation
Types of instrumentation and measurements associated with the OSMOSIS observational campaign:
- Ocean gliders
- Wave rider buoys
- Towed SeaSoar surveys
- Microshear measurements
- Moored current meters, conductivity-temperature sensors and ADCPs
- Traditional shipboard measurements (including CTD, underway, discrete nutrients, LADCP, ADCP).
Contacts
| Collaborator | Organisation |
|---|---|
| Prof. Stephen Belcher | University of Reading, U.K |
| Dr. Alberto C Naveira Garabato | University of Southampton, U.K |
Data Activity or Cruise Information
Cruise
| Cruise Name | D381A |
| Departure Date | 2012-08-28 |
| Arrival Date | 2012-09-13 |
| Principal Scientist(s) | Alberto C Naveira Garabato (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 |
