Metadata Report for BODC Series Reference Number 749501
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
RV CORYSTES: CRUISE 1X/04: CTD Data Quality Report
No TSEDBSCL data were produced on the 21/01/2004 at 15:34:00 and therefore the channel is not present for this cast.
TEMPCC01, and associated channel PSALCC01, have been flagged at the beginning and end of the cast on the 20/01/2004 at 11:15:00 as the data are highly variable.
Highly variable TEMPCC01, and associated channel PSALCC01, date have been flagged for all depths for casts:
PAR data have not been made available in the final QXF file as they were of unusable quality. They can however be made available for a limited number of casts upon request.
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 Integrated CTD (ICTD) Profiler
The FSI ICTD is designed to collect high precision conductivity, temperature and pressure data with self calibrating electronics. This instrument can support five primary sensors (including up to three temperature sensors) and can be coupled with a water bottle sampler. The ICTD is equipped with a titanium housing rated to 7000 m and has a sampling rate of 32 Hz.
Three temperature sensors are available: primary platinum, redundant platinum and exposed thermistor. Any combination of these can be used in the primary channels. The instrument also has multiple RS-232 serial inputs for a variety of sensors including: ADCP, Benthos PSA-916 Altimeter and WetLabs SAFire. There are an additional eight DC input channels that can support virtually any sensor that has a DC output.
Specifications:
| Parameter | Conductivity | Temperature | Pressure |
| Sensor | Inductive cell | Platinum thermometer | Precision-machined Silicon |
| Range | 0 to 70 mS cm-1 | -2 to 35°C | Customer specified |
| Accuracy | ±0.002 mS cm-1 | 0.002°C | ±0.01 % full scale |
| Resolution | 0.0001 mS cm-1 | 0.00005°C | 0.0004 % full scale |
| Response | 5.0 cm at 1 ms-1 | 150 ms Platinum 20 ms Thermistor* | 25 ms |
*Optional
Further details can be found in the manufacturer's specification sheet.
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 |
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.
RV CORYSTES: CRUISE 1X/04: CTD data document
Sampling strategy
A total of 56 full depth CTD profiles were obtained during January 2004. CTD were deployed during this cruise to the North Sea at the Outer Gabbard, Thames region, English Channel, SW Approaches, Bristol Channel and the Irish Sea.
For further detail refer to the cruise report.
Instrumentation and data processing
The CTD used was a Falmouth Scientific Inc., with serial number 1351. Samples were collected for salinity analysis (using a Guildline salinometer) to derive a calibration for the instrument conductivity sensor, and a pair of digital reversing thermometers were used to compare with the CTD temperature estimates. A CHELSEA fluorometer and SEAPOINT turbidity sensor were used at all CTD stations. A LICOR photosynthetically-active-radiation (PAR) sensor (with a six-decade log amplifier) was fitted to the rosette at all CTD stations. Chlorophyll samples were collected to calibrate the fluorometer and samples for suspended particulate matter analysis were used to calibrate the turbidity sensor.
A list of calibrated parameters and instrumentation used is shown below.
| Measurement | Parameter | Units | Instrumentation | Calibration |
|---|---|---|---|---|
| pres | Pressure | dbar | Falmouth Scientific Instruments Integrated CTD Profiler | Corrected from deck measurements |
| temp | Temperature | °C | Falmouth Scientific Instruments Integrated CTD Profiler | Calibrated December 2004 |
| salinity | Salinity | dimensionless | Falmouth Scientific Instruments Integrated CTD Profiler | Calibrated against bottle samples |
| turb | Turbidity | volts | Seapoint Turbidity sensor | Calibrated against bottle samples |
| sl | Suspended Load | mg/L | Seapoint Turbidity sensor | Used to calibrate turbidity |
| light | Light | volts | Licor Light sensor (s/n 5672) | Used to calculate PAR |
| fluor | Fluorescence | volts | Seapoint Fluorometer | Calibrated against bottle samples |
Change of sensors during cruise: None reported.
The data sets were calibrated by CEFAS
BODC post-processing and screening
Reformatting
Data for the 56 CTD casts was provided in ASCII format as .cor files. The data files were converted from ASCII format into BODC internal format (QXF) to allow the use of in-house visualisation tools. Originators Parameters have been mapped to BODC parameter codes. No unit conversions were necessary.
| Originators Parameter | Units | Description | BODC Parameter | BOBC Units | Comments |
|---|---|---|---|---|---|
| Pres | dbars | Pressure | PRESPR01 | dbars | Calibration by Cefas |
| Temp | °C | Temperature | TEMPCC01 | °C | Calibration by Cefas |
| Salinity | dimensionless | Salinity | PSALCC01 | dimensionless | Calibration by Cefas |
| Depth | m | Depth | DEPHPR01 | m | Calculated from pressure readings |
| sl | mg/L | Suspended load | TSEDBSCL | mg/L | Calibrated by Cefas |
| Chl | mg/m3 | Chlorophyll | CPHLPS01 | mg/m3 | Calibrated by Cefas |
| Pot | deg C | Potential Temperature | - | - | Not transferred. |
| SVEL | m/sec | Sound Velocity | - | - | Not transferred. |
| Sig-th | kg m-3 | Sigma-Theta | - | - | Not transferred. |
| sigma-t | kg m-3 | Density | - | - | Not transferred. |
| Svan | 10-8 | Specific volume anomaly | - | - | Not transferred. |
| dynht | - | Dynamic Height | - | - | Not transferred. |
| bvf | cph | Brunt Wiesler frequency | - | - | Not transferred. |
| Turb | Volts | Turbidity | - | - | Not transferred. |
| light | Volts | - | - | - | Not transferred. |
| PAR | µE M-2 S-1 | Photosynthetically Active Radiation | - | - | Not transferred. |
| Fluor | Volts | Fluorescence | - | - | Not transferred. |
Certain parameters were not transferred as they can be readily reproduced from other data; others were not transferred due to their data quality (see Data Quality Report).
The reformatted data were visualised using in-house software. Any suspect data were flagged, using the BODC quality control flags.
Project Information
No Project Information held for the Series
Data Activity or Cruise Information
Cruise
| Cruise Name | COR1X/04 |
| Departure Date | 2004-01-12 |
| Arrival Date | 2004-01-25 |
| Principal Scientist(s) | David Brian Sivyer (Centre for Environment, Fisheries and Aquaculture Science Lowestoft Laboratory) |
| Ship | RV Corystes |
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 |
