Metadata Report for BODC Series Reference Number 1199795
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
AMT Bio-Optics Data Quality - Flow-through measurements
The data were screened using the BODC in-house software, Edserplo.
All parameters had 'N' flags applied during transfer for any null data. 'M' flags were automatically assigned during transfer to values outside the minimum and maximum permissable values. Data were occasionally manually flagged with 'M' during screening when the data scientist considered the data to be suspect. This included solitary spikes and periods when the instrument might be adjusting to conditions after failure, redeployment or period of null data.
The light parameters (ATTNXAC9, ABSULT01 and ABSPXAC9) regularly have periods of null data.
Data Access Policy
Academic domain data
These data have no specific confidentiality restrictions for academic users. However, users must acknowledge data sources as it is not ethical to publish data without proper attribution. Any publication or other output resulting from usage of the data should include an acknowledgment.
The recommended acknowledgment is:
"This study uses data from data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."
Narrative Documents
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.
AMT Bio-Optics Instrumentation - Flow-through measurements
| Instrument | Serial number | Parameter |
|---|---|---|
| WET Labs ECO-VSF | 061g | Total optical backscattering at 532 nm |
| WET Labs WETStar fluorometer | 1048p | Chlorophyll fluorescence |
| WET Labs ac-9 Spectrophotometer | 194 | Absorption and attenuation |
| SeaBird SBE45 | 4530785-0102 | Temperature and Salinity |
WETLabs ECO-VSF Optical Backscatter Meter
The ECO-VSF is a scattering meter designed to measure the angular distribution of scattered radiation of the backward hemisphere. The instrument measures optical scattering at three angles (100°, 125° and 150°), providing the shape of the Volume Scattering Function (VSF) throughout the backscattering region. Interpolation and extrapolation are used to determine scattering at intermediate angles. It also provides the total backscatter coefficient between 90° and 180° by integration and extrapolation.
The ECO-VSF comes in five versions, with a variety of power options, sampling strategies and anti-fouling capabilities:
- The standard ECO-VSF configuration provides an RS-232 serial output with 4000-count range and can be programmed for continuous operation or periodic sampling.
- The ECO-VSF(RT) provides an RS-232 serial output with 4000-count range and can be programmed for continuous operation.
- The ECO-VSFS adds anti-fouling capabilities to the standard ECO-VSF.
- The ECO-VSFB is a self-recording version of the ECO-VSF with internal batteries for autonomous operation.
- The ECO-VSFSB adds anti-fouling capabilities to the ECO-VSFSB.
The specifications below are common to all versions.
Specifications
| Wavelength | 470, 532 or 660 nm |
| Sensitivity | 1.24x10-5 |
| Typical range | ~ 0.0012-5 m-1 |
| Linearity | 99 % R2 |
| Temperature range | 0-30° |
| Depth rating | 600 m (standard) |
| Sample rate | up to 8 Hz |
| Pressure sensor | optional |
| Temperature sensor | optional |
Further details can be found in the manufacturer's specification sheet.
WETLabs ac-9 and ac-s Spectral Absorption and Attenuation Meters
The WETLabs ac-9 and ac-s meters measure the spectral transmittance and spectral absorption of water, allowing determination of absorption and beam attenuation coefficients. The instruments incorporate a flow-through system and a dual path configuration that permits concurrent measurement of both coefficients along a 25 cm path. The ac-9 provides measurements at nine wavelengths in the range 412-715 nm, whereas the ac-s provides measurements at >80 wavelengths from 400-730 nm.
Specifications
| Parameters | ac-9 | ac-s |
|---|---|---|
| Temperature range | 0-30 ° | 0-30 ° |
| Rated depth | 500 or 5000 m | 500 m |
| Spectral range | 412-715 nm | 400-730 nm |
| Band-pass | 10 nm per channel | 15 nm per channel |
| Pathlength | 25 cm (optional 10 cm) | 25 cm (optional 10 cm) |
| Beam cross-section | 8 mm dia. (nominal) | 8 mm dia. (nominal) |
| Linearity | >=99 % R2 | >=99 % R2 |
| Wavelength output | 9 | 80-90 in 4 nm steps |
| Accuracy | ±0.01 m-1 | ±0.01 m-1 |
| Dynamic range | 0.001-10 m-1 | 0.001-10 m-1 |
Further details can be found in the manufacturer's specification sheet.
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.
AMT Bio-Optics - Flow-through Processing Document
Data Acquisition and Analysis
This system operates semi-continuously with water from the ship's non-toxic sea water supply Every 4-12 minutes temperature and salinity are measured (with a SeaBird sensor), chlorophyll fluorescence (WET Labs WETStar), total backscattering at 532 nm (bbtot; WET Labs ECO-VSF), acidified backscattering (bbacid; backscattering of the seawater suspension after the pH has been lowered to dissolve calcite and aragonite), and acid-labile backscattering (bb'; the difference between the bbtot and bbacid). The chlorophyll data were calibrated against sample data.
BODC Data Processing Procedures
Data were submitted to BODC as a .out file, which was then saved to the archive following BODC procedure. Date were submitted in a .out text file containing temperature, salinity and fluorescence from sea surface water from the ship's non-toxic water supply. Light absorption and attenuation were also supplied at 9 different wavelengths along with the backscattering and acid labile backscattering. Additional metadata was supplied including: cruise, latitude, longitude, date and time. The MicroSAS radiance parameters were also submitted in the same file but banked separately to the NODB.
The data were converted from the comma delimited SeaBass format into BODC internal format using a standard BODC transfer.
Parameter codes defined in BODC parameter dictionary were assigned to the variables as shown in the table below. No unit conversions were necessary as the data submitted was already units from the BODC parameter dictiionary.
Parameter Mapping Table
| Originator's Parameter | Description | Units | BODC Parameter Code | Description | Units | Comments |
|---|---|---|---|---|---|---|
| lat | Latitude, as mentioned on the originator's file | degrees | ALATGP01 | Latitude north (WGS84) by unspecified GPS system Global Positioning System (receiver type unspecified) | degrees | N/A |
| lon | Longitude, as mentioned on the originator's file | degrees | ALONGP01 | Longitude east (WGS84) by unspecified GPS system Global Positioning System (receiver type unspecified) | degrees | N/A |
| bbp532 | Backscattering coefficient of particles(*) | m-1 | BS532VSF | Attenuance due to backscatter (532nm wavelength) in the water body by scattering photometer and calibration to read zero in clear water with computation from volume scatter data | m-1 | N/A |
| agp | Absorption Coefficient of Gelbstoff + particles(*) | m-1 | ABSPXAC9 | Light absorbance (unspecified single wavelength) by the water body by transmissometer and calibration to read zero in clear water | m-1 | N/A |
| ag | Absorption Coefficient of Gelbstoff(*) | m-1 | ABSULT01 | Light absorbance (unspecified single wavelength) per unit length of the water body dissolved plus reactive particulate <0.2 µm by transmissometer and calibration to read zero in clear water | m-1 | N/A |
| cgp | Absorption Coefficient of Gelbstoff + particles(*) | m-1 | ATTNXAC9 | Attenuance (unspecified single wavelength) per unit length of the water body by transmissometer and calibration to read zero in clear water | m-1 | N/A |
| wavelength | Wavelength(*) | nm | LAMBIN01 | Wavelength of electromagnetic radiation measurement | nm | N/A |
| Sal | Salinity | - | PSALSU01 | Practical salinity of the water body by thermosalinograph and computation using UNESCO 1983 algorithm and NO calibration against independent measurements | - | N/A |
| Temp | Water temperature | degrees Celsius | TEMPSU01 | Temperature of the water body by thermosalinograph and NO verification against independent measurements | degrees Celsius | N/A |
| Chl | Fluorometrically/spectrophotometrically-derived chlorophyll a(*) | mg m-3 | CPHLUT01 | Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate >unknown phase] by through-flow fluorometer plumbed into non-toxic supply and calibration against sample data. | mg m-3 | N/A |
Screening
Once transferred the reformatted data were imported into the BODC in-house visualisation software, Edserplo. Data were appropriately flagged and double checked for any anomalous results. Further details are given in the data quality report.
Project Information
The Atlantic Meridional Transect - Phase 2 (2002-2006)
Who was involved in the project?
The Atlantic Meridional Transect Phase 2 was designed by and implemented by a number of UK research centres and universities. The programme was hosted by Plymouth Marine Laboratory in collaboration with the National Oceanography Centre, Southampton. The universities involved were:
- University of Liverpool
- University of Newcastle
- University of Plymouth
- University of Southampton
- University of East Anglia
What was the project about?
AMT began in 1995, with scientific aims to assess mesoscale to basin scale phytoplankton processes, the functional interpretation of bio-optical signatures and the seasonal, regional and latitudinal variations in mesozooplankton dynamics. In 2002, when the programme restarted, the scientific aims were broadened to address a suite of cross-disciplinary questions concerning ocean plankton ecology and biogeochemistry and the links to atmospheric processes.
The objectives included the determination of:
- how the structure, functional properties and trophic status of the major planktonic ecosystems vary in space and time
- how physical processes control the rates of nutrient supply to the planktonic ecosystem
- how atmosphere-ocean exchange and photo-degradation influence the formation and fate of organic matter
The data were collected with the aim of being distributed for use in the development of models to describe the interactions between the global climate system and ocean biogeochemistry.
When was the project active?
The second phase of funding allowed the project to continue for the period 2002 to 2006 and consisted of six research cruises. The first phase of the AMT programme ran from 1995 to 2000.
Brief summary of the project fieldwork/data
The fieldwork on the first three cruises was carried out along transects from the UK to the Falkland Islands in September and from the Falkland Islands to the UK in April. The last three cruises followed a cruise track between the UK and South Africa, only deviating from the traditional transect in the southern hemisphere. During this phase the research cruises sampled further into the centre of the North and South Atlantic Ocean and also along the north-west coast of Africa where upwelled nutrient rich water is known to provide a significant source of climatically important gases.
Who funded the project?
Natural Environment Research Council (NERC)
Data Activity or Cruise Information
Cruise
| Cruise Name | D299 (AMT17) |
| Departure Date | 2005-10-15 |
| Arrival Date | 2005-11-28 |
| Principal Scientist(s) | Patrick M Holligan (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 |
