Metadata Report for BODC Series Reference Number 750606
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
Data Access Policy
Public domain data
These data have no specific confidentiality restrictions for 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 the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."
Narrative Documents
Falmouth Scientific NXIC CTD Series
The FSI NXIC CTD Series is a collection of rugged Conductivity-Temperature-Depth profilers that utilise the patented Non-eXternal Inductive Cell (NXIC) conductivity sensor, which was originally developed for the US Navy DT-705 Sound Velocity/Salinity sensor. The CTDs are fast sampling, fully integrated instruments with optional battery power, datalogging and external analog sensor input.
Models in the collection include the NXIC CT Bio Direct Read-500M, NXIC CTD Bio Direct Read-500M, NXIC CTD Bio Auto-500M, NXIC CTD Direct Read-500M, NXIC CTD Direct Read-700M, NXIC CTD Auto-500M, NXIC CTD Auto-700M, NXIC CTD-ADC with external sensors, and the NXIC ETSG Thermosalinograph. Parameters are measured to an accuracy ranging from 0.002-0.010 mS/cm for conductivity, 0.005 degC for temperature and 0.08% for full scale pressure. Now marketed by Teledyne RD Instruments.
Specifications
| Conductivity | Temperature | Pressure | |
|---|---|---|---|
| Sensor type | Inductive cell | Thermistor | Precision-machined Silicon |
| Range | 0 to 9.0 S m-1 | -5 to 45°C | user specified |
| Accuracy | ± 0.0002 S m-1 | ± 0.005°C | 0.08 % full scale |
| Stability | ± 0.00005 S cm-1 month-1 | 0.0005°C month-1 | ± 0.004 % |
| Resolution | 0.00001 S m-1 | 0.001°C | 0.001 % full scale |
| Response | 5.0 cm at 1 m sec-1 flow | 100 msec | 25 msec |
Further details can be found in the manufacturer's specification sheet and Series Brochure.
Seapoint Chlorophyll Fluorometer
The Seapoint Chlorophyll Fluorometer (SCF) is a low power instrument for in situ measurements of chlorophyll a. The SCF uses modulated blue LED lamps and a blue excitation filter to excite chlorophyll a. The fluorescent light emitted by the chlorophyll a passes through a red emission filter and is detected by a silicon photodiode. The low level signal is then processed using synchronous demodulation circuitry which generates an output voltage proportional to chlorophyll a concentration. The SCF may be operated with or without a pump.
Sensor specifications, current at August 2006, are given in the table below. More information can be found at the manufacturer's web site.
Sensor Specifications
| Power requirements | 8 - 20 VDC, 15 mA avg., 27 mA pk. |
|---|---|
| Output | 0 - 5.0 VDC |
| Output Time Constant | 0.1 sec. |
| Power-up transient period | < 1 sec. |
| Excitation Wavelength | 470 nm CWL, 30 nm FWHM |
| Emission Wavelength | 685 nm CWL, 30 nm FWHM |
| Sensing Volume | 340 mm3 |
| Minimum Detectable Level | 0.02 µg l-1 |
| Gain | Sensitivity, V µg-1 l-1 | Range, µg l-1 | |
|---|---|---|---|
| Sensitivity/Range | 30x 10x 3x 1x | 1.0 0.33 0.1 0.033 | 5 15 50 150 |
LI-COR LI-192 Underwater Quantum Sensor
The LI-192 Underwater Quantum Sensor is used to measure photosynthetic photon flux density and is cosine corrected. The sensor is often referred to as LI-192SA or LI-192SB (the LI-192SB model was superseded by LI-192SA). One of the main differences is that the LI-192SA model includes a built-in voltage output for interfacing with NexSens iSIC and SDL data loggers.
Sensor specifications, current at January 2012, are given in the table below. More information can be found in the manufacturer's LI-192SA andLI-192SB specification sheets.
Sensor Specifications
(Specifications apply to both models unless otherwise stated)
| Absolute Calibration | ± 5 % in air traceable to NBS. |
|---|---|
| Sensitivity | Typically 3 µA per 1000 µmol s-1 m-2 for LI-192SB and 4 µA per 1000 µmol s-1 m-2 for LI-192SA in water. |
| Linearity | Maximum deviation of 1 % up to 10,000 µmol s-1 m-2. |
| Stability | < ± 2 % change over a 1 year period. |
| Response Time | 10 µs. |
| Temperature Dependence | ± 0.15 % per °C maximum. |
| Cosine Correction | Optimized for both underwater and atmospheric use. |
| Azimuth | < ± 1 % error over 360 ° at 45 ° elevation. |
| Detector | High stability silicon photovoltaic detector (blue enhanced). |
| Sensor Housing | Corrosion resistant metal with acrylic diffuser for both saltwater and freshwater applications. Waterproof to withstand 800 psi (5500 kPa) (560 meters). |
Seapoint Turbidity Meter
The Seapoint Turbidity Meter detects light scattered by particles suspended in water, generating an output voltage proportional to turbidity or suspended solids. Range is selected by two digital lines which can be hard wired or microprocessor controlled, thereby choosing the appropriate range and resolution for measurement of extremely clean to very turbid waters. The offset voltage is within 1 mV of zero and requires no adjustment across gains. The optical design confines the sensing volume to within 5 cm of the sensor allowing near-bottom measurements and minimizing errant reflections in restricted spaces.
Sensor specifications, current at August 2006, are given in the table below.
Sensor Specifications
| Power requirements | 7 - 20 VDC, 3.5 mA avg., 6 mA pk. |
|---|---|
| Output | 0 - 5.0 VDC |
| Output Time Constant | 0.1 sec. |
| RMS Noise> | < 1 mV |
| Power-up transient period | < 1 sec. |
| Light Source Wavelength | 880 nm |
| Sensing Distance (from windows) | < 5 cm (approx.) |
| Linearity | < 2% deviation 0 - 750 FTU |
| Gain | Sensitivity (mV FTU-1) | Range (FTU) | |
|---|---|---|---|
| Sensitivity/Range | 100x 20x 5x 1x | 200 40 10 2 | 25 125 500 ** |
** output is non-linear above 750 FTU.
Further details can be found in the manufacturer's specification sheet.
Project Information
Cefas project A1225 - North Sea Dogger Bank
This project is aimed at achieving a better understanding of the dynamics of the circulation processes of the seas around the UK. In order to characterise the extent and nature of density driven and seasonal jet-like circulation which acts as a direct and rapid pathway for transport of material. This project consists of three cruises in Autumn 2004: CO13/04, CE12/04 and CE14/04 which aim to examine change over this 2 month period from the warmest, most stratified conditions through to the breakdown period.
The chosen area of interest is the Northern flank of the Dogger Bank along a line that was previously visited in June and August 1999, 2000 and in 2001. In order to identify the structure of the mixing in the bottom region, and for comparisons with models, a thermistor chain and ADCPS will be deployed for the period between the cruises as this will enable the exact timing and nature of breakdown to be indentified. As well as the thermohaline structure the phtyoplankton structure and nutrient uptake will be investigated. With regular samples taken for Isotope analysis. The project aims can be summarised as:
1. To characterise the hydrographic structure associated with the frontal regions and investigate the transport pathways. By use of towed undulating CTDs.
2. Deploy ARGOS drifting buoys to quantify the Lagrangian circulation.
3. Deploy Mooring (ADCP and thermistor chain) to study the mixing processes in the transitional region.
4. Conduct experiments for phytoplankton production both by Nitrogen uptake method and by Carbon14 labelling. (This was not conducted as permission was not obtained for licence despite many months notice).
5. Take samples for Isotope analysis.
A summary of the cruises is shown below.
| Cruise | Departure date | Return date | Numbeer of CTD casts | Track charts |
|---|---|---|---|---|
| CO 13/04 | 31st Aug 2004 | 4th Sep 2004 | 11 | Cruise Track |
| CE 12/04 | 30th Sep 2004 | 9th Oct 2004 | 29 | Cruise Track |
| CE 14/04 | 22nd Oct 2004 | 1st Nov 2004 | 82 | Cruise Track |
Data Activity or Cruise Information
Cruise
| Cruise Name | 14/04 |
| Departure Date | 2004-10-22 |
| Arrival Date | 2004-11-01 |
| Principal Scientist(s) | Stephen Robin Dye (Centre for Environment, Fisheries and Aquaculture Science Lowestoft Laboratory) |
| Ship | RV Cefas Endeavour |
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 |
