Metadata Report for BODC Series Reference Number 1144850
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 |
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Time Co-ordinates(UT) |
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Parameters |
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Problem Reports
No Problem Report Found in the Database
Cruise 0710A Data Quality Report
The originator stated that for casts Nm07/10/33 and Nm07/10/34, PSALCC01 and CNLCCI1 had quality issues so these channels were flagged M. The following cycles were flagged during screening:
| ISHREF | CSHOID | PSALCC01 | CPHLPM01 | TURBXXXX |
|---|---|---|---|---|
| 1144721 | Nm07/10/1 | 1, 38 (M) | ||
| 1144745 | Nm07/10/3 | 1-2 (M) | ||
| 1144782 | Nm07/10/7 | 23, 41 (M) | ||
| 1144813 | Nm07/10/10 | 1 (M) | 1 (M) | |
| 1144850 | Nm07/10/14 | 25 (M) | 1-2 (M) | |
| 1144862 | Nm07/10/15 | 59 (M) | ||
| 1144917 | Nm07/10/20 | 35 (M) | ||
| 1144942 | Nm07/10/23 | 1, 13-14 (M) | ||
| 1144966 | Nm07/10/25 | 36 (M) | ||
| 1144991 | Nm07/10/27 | 1-2, 52 (M) | ||
| 1145030 | Nm07/10/31 | 1-2 (M) | ||
| 1145042 | Nm07/10/32 | 1 (M) | ||
| 1145054 | Nm07/10/33 | 33 (M) | ||
| 1145091 | Nm07/10/36 | 1-2, 82 (M) | ||
| 1145109 | Nm07/10/37 | 1, 25, 46 (M) | ||
| 1145122 | Nm07/10/39 | 46-47 (M) | ||
| 1145134 | Nm07/10/40 | 22, 34 (M) | ||
| 1145195 | Nm07/10/45 | 1-2, 42 (M) | ||
| 1145202 | Nm07/10/46 | 1 (M) | ||
| 1145588 | Nm07/10/81 | 8 (M) |
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
Instrument Description
CTD Unit and Auxiliary Sensors
A Sea-Bird Electronics SBE 19 plus V2 SEACAT CTD unit was used. Water samples were collected with a Knudsen reversing water bottle, which was attached to wire 1m above the CTD frame. The CTD unit included the following sensors.
| Sensor | Manufacturer | Model | Serial number | Calibration date |
|---|---|---|---|---|
| Pressure | Paroscientific | Digiquartz | 6029 | 2010-04-29 |
| Temperature | Sea-Bird | SBE3 | 6029 | 2010-04-28 |
| Conductivity | Sea-Bird | SBE4 | 6029 | 2010-04-30 |
| Fluorometer and Turbidity Sensor | Wet Labs | ECO FLNTU | 0947 | 2008-03-05 |
Sea-Bird Electronics SBE 911 and SBE 917 series CTD profilers
The SBE 911 and SBE 917 series of conductivity-temperature-depth (CTD) units are used to collect hydrographic profiles, including temperature, conductivity and pressure as standard. Each profiler consists of an underwater unit and deck unit or SEARAM. Auxiliary sensors, such as fluorometers, dissolved oxygen sensors and transmissometers, and carousel water samplers are commonly added to the underwater unit.
Underwater unit
The CTD underwater unit (SBE 9 or SBE 9 plus) comprises a protective cage (usually with a carousel water sampler), including a main pressure housing containing power supplies, acquisition electronics, telemetry circuitry, and a suite of modular sensors. The original SBE 9 incorporated Sea-Bird's standard modular SBE 3 temperature sensor and SBE 4 conductivity sensor, and a Paroscientific Digiquartz pressure sensor. The conductivity cell was connected to a pump-fed plastic tubing circuit that could include auxiliary sensors. Each SBE 9 unit was custom built to individual specification. The SBE 9 was replaced in 1997 by an off-the-shelf version, termed the SBE 9 plus, that incorporated the SBE 3 plus (or SBE 3P) temperature sensor, SBE 4C conductivity sensor and a Paroscientific Digiquartz pressure sensor. Sensors could be connected to a pump-fed plastic tubing circuit or stand-alone.
Temperature, conductivity and pressure sensors
The conductivity, temperature, and pressure sensors supplied with Sea-Bird CTD systems have outputs in the form of variable frequencies, which are measured using high-speed parallel counters. The resulting count totals are converted to numeric representations of the original frequencies, which bear a direct relationship to temperature, conductivity or pressure. Sampling frequencies for these sensors are typically set at 24 Hz.
The temperature sensing element is a glass-coated thermistor bead, pressure-protected inside a stainless steel tube, while the conductivity sensing element is a cylindrical, flow-through, borosilicate glass cell with three internal platinum electrodes. Thermistor resistance or conductivity cell resistance, respectively, is the controlling element in an optimized Wien Bridge oscillator circuit, which produces a frequency output that can be converted to a temperature or conductivity reading. These sensors are available with depth ratings of 6800 m (aluminium housing) or 10500 m (titanium housing). The Paroscientific Digiquartz pressure sensor comprises a quartz crystal resonator that responds to pressure-induced stress, and temperature is measured for thermal compensation of the calculated pressure.
Additional sensors
Optional sensors for dissolved oxygen, pH, light transmission, fluorescence and others do not require the very high levels of resolution needed in the primary CTD channels, nor do these sensors generally offer variable frequency outputs. Accordingly, signals from the auxiliary sensors are acquired using a conventional voltage-input multiplexed A/D converter (optional). Some Sea-Bird CTDs use a strain gauge pressure sensor (Senso-Metrics) in which case their pressure output data is in the same form as that from the auxiliary sensors as described above.
Deck unit or SEARAM
Each underwater unit is connected to a power supply and data logging system: the SBE 11 (or SBE 11 plus) deck unit allows real-time interfacing between the deck and the underwater unit via a conductive wire, while the submersible SBE 17 (or SBE 17 plus) SEARAM plugs directly into the underwater unit and data are downloaded on recovery of the CTD. The combination of SBE 9 and SBE 17 or SBE 11 are termed SBE 917 or SBE 911, respectively, while the combinations of SBE 9 plus and SBE 17 plus or SBE 11 plus are termed SBE 917 plus or SBE 911 plus.
Specifications
Specifications for the SBE 9 plus underwater unit are listed below:
| Parameter | Range | Initial accuracy | Resolution at 24 Hz | Response time |
|---|---|---|---|---|
| Temperature | -5 to 35°C | 0.001°C | 0.0002°C | 0.065 sec |
| Conductivity | 0 to 7 S m-1 | 0.0003 S m-1 | 0.00004 S m-1 | 0.065 sec (pumped) |
| Pressure | 0 to full scale (1400, 2000, 4200, 6800 or 10500 m) | 0.015% of full scale | 0.001% of full scale | 0.015 sec |
Further details can be found in the manufacturer's specification sheet.
Sea-Bird SBE 19 and SBE 19plus SEACAT Profiler CTDs
The SBE 19 SEACAT Profiler is a self-contained, battery powered, pumped CTD system designed to measure conductivity, temperature, and pressure in marine or fresh water environments to depths of 10,500 meters. It was replaced by the SBE 19plus model in 2001. An updated version of this instrument is the SBE 19plus V2, which incorporates an electronics upgrade and additional features, with six differentially amplified A/D input channels, one RS-232 data input channel, and 64 MB FLASH memory.
The standard CTD unit comes with a plastic housing (rated to 600 m), although this can be replaced by titanium housing for depths up to 7000 m. It is typically used for CTD profiling although a conversion kit is available for mooring deployments. The CTD can also be attached to an SBE 36 CTD Deck Unit and Power/Data Interface Module (PDIM) for real-time operation on single-core armored cable up to 10,000 m.
Specifications
| Parameter | SBE 19 | SBE 19plus |
|---|---|---|
| Temperature | Range: -5 to +35 °C Accuracy: 0.01 °C Resolution: 0.001 °C Calibration: +1 to +32 °C* | Range: -5 to +35 °C Accuracy: 0.005 °C Resolution: 0.0001 °C Calibration: +1 to +32 °C* |
| Conductivity | Range: 0 to 7 S m-1 (0 to 70 mmho cm-1) Accuracy: 0.001 S m-1 Resolution: 0.0001 S m-1 Calibration: 0 to 7 S m-1. Physical calibration over the range 1.4 - 6 S m-1* | Range: 0 to 9 Sm-1 Accuracy: 0.0005 Resolution: 0.00005 (most oceanic waters, resolves 0.4 ppm in salinity); 0.00007 (high salinity waters, resolves 0.4 ppm in salinity); 0.00001 (fresh waters, resolves 0.1 ppm in salinity) Calibration: 0 to 9 S m-1. Physical calibration over the range 1.4 - 6 S m-1* |
| Strain gauge pressure sensor | Range: 0 to100, 150, 300, 500, 1000, 1500, 3000, 5000, 10000 or 15000 psia Accuracy: 0.25% of full scale range (100 - 1500 psia); 0.15% of full scale range (3000 - 15000 psia) Resolution: 0.015% of full scale Calibration: 0 to full scale in 20% steps | Range: 0 to 20, 100, 350, 1000, 2000, 3500 or 7000 m Accuracy: 0.1% of full scale range Resolution: 0.002% of full scale range Calibration: ambient pressure to full scale range in 5 steps |
*Measurements outside this range may be at slightly reduced accuracy due to extrapolation errors.
Options and accessories
Additional sensors can be attached to the CTD, including:
- high accuracy Paroscientific Digiquartz pressure sensor (depth range 0 to 20, 60, 130, 200, 270, 680, 1400, 2000, 4200, 7000 or 10500 m; accuracy 0.02% of full scale; resolution 0.0025% of full scale)
- Dissolved Oxygen (SBE 43 DO Sensor)
- pH* (SBE 18 pH Sensor or SBE 27 pH/ORP Sensor)
- fluorescence
- radiance (PAR)
- light transmission
- optical backscatter (turbidity)
The standard SBE 5M pump may be replaced by an SBE 5P (plastic housing) or 5T (titanium housing) pump for use with dissolved oxygen and/or other pumped sensors. Further details can be found in the manufacturer's SBE 19plus V2 instrument specification or theSBE 19 andSBE 19 plus user guides.
WETLabs ECO FLNTU fluorescence and turbidity sensor
The Environmental Characterization Optics (ECO) Fluorometer and Turbidity (FLNTU) sensor is a dual wavelength, single-angle instrument that simultaneously determines chlorophyll fluorescence and turbidity. It is easily integrated in CTD packages and provides a reliable turbidity measurement that is not affected by Colored Dissolved Organic Matter (CDOM) concentration.
The FLNTU can operate continuously or periodically and has two different types of connectors to output the data. There are 5 other models that operate the same way as this instrument but have slight differences, as stated below:
- FLNTU(RT) - has an analog an RS-232 serial output and operates continuously, when power is supplied
- FLNTU(RT)D - similar to the FLNTU(RT) but has a depth rating of 6000 m
- FLNTUB - has internal batteries for autonomous operation
- FLNTUS - has an integrated anti-fouling bio-wiper
- FLNTUSB - has the same characteristics as the FLNTUS but with internal batteries for autonomous operation
Specifications
| Temperature range | 0 to 30°C |
| Depth rating | 600 m (standard) 6000 m (deep) |
| Turbidity | |
| Wavelength | 700 nm |
| Sensitivity | 0.01 NTU |
| Typical range | 0.01 to 25 NTU |
| Fluorescence | |
| Wavelength | 470 nm (excitation), 695 nm (emission) |
| Sensitivity | 0.01 µg L-1 |
| Typical range | 0.01 to 50 µg L-1 |
| Linearity | 99% R2 |
Further details can be found in the manufacturer's specification sheet.
Paroscientific Absolute Pressure Transducers Series 3000 and 4000
Paroscientific Series 3000 and 4000 pressure transducers use a Digiquartz pressure sensor to provide high accuracy and precision data. The sensor comprises a quartz crystal resonator that responds to pressure-induced stress, and temperature is measured for thermal compensation of the calculated pressure.
The 3000 series of transducers includes one model, the 31K-101, whereas the 4000 series includes several models, listed in the table below. All transducers exhibit repeatability of better than ±0.01% full pressure scale, hysteresis of better than ±0.02% full scale and acceleration sensitivity of ±0.008% full scale /g (three axis average). Pressure resolution is better than 0.0001% and accuracy is typically 0.01% over a broad range of temperatures.
Differences between the models lie in their pressure and operating temperature ranges, as detailed below:
| Model | Max. pressure (psia) | Max. pressure (MPa) | Temperature range (°C) |
|---|---|---|---|
| 31K-101 | 1000 | 6.9 | -54 to 107 |
| 42K-101 | 2000 | 13.8 | 0 to 125 |
| 43K-101 | 3000 | 20.7 | 0 to 125 |
| 46K-101 | 6000 | 41.4 | 0 to 125 |
| 410K-101 | 10000 | 68.9 | 0 to 125 |
| 415K-101 | 15000 | 103 | 0 to 50 |
| 420K-101 | 20000 | 138 | 0 to 50 |
| 430K-101 | 30000 | 207 | 0 to 50 |
| 440K-101 | 40000 | 276 | 0 to 50 |
Further details can be found in the manufacturer's specification sheet.
BODC Processing
Data were received by BODC in one ASCII format file that was subsequently split into 49 separate files, one for each CTD profile. The series were reformatted to the internal QXF format using established procedures. Sample calibrations derived by the data originator were applied to the conductivity and fluorescence data. The following table details mapping of variables to BODC parameter codes.
| Original parameter name | Original Units | Description | BODC Parameter Code | BODC Units | Comments |
|---|---|---|---|---|---|
| Pressure | Decibars | Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level | PRESPR01 | Decibars | |
| Temperature | °C | Temperature of the water body by CTD or STD | TEMPST01 | °C | |
| Conductivity | mS cm-1 | Electrical conductivity of the water body by in-situ conductivity cell and calibration against independent measurements | CNCLCCI1 | S m-1 | Conversion by transfer (mS cm-1 x 0.1). Sample calibrations applied by transfer. |
| Salinity | Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm and calibration against independent measurements | PSALCC01 | Dimensionless | Derived by the transfer | |
| Fluorescence | µg l-1 | Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate phase] by in-situ chlorophyll fluorometer and calibration against sample data | CPHLPS01 | mg m-3 | Sample calibrations applied by transfer |
| Turbidity | Nephelometric Turbidity Unit | Turbidity of the water body | TURBXXXX | Nephelometric Turbidity Unit |
Following transfer to QXF, the data were screened using BODC's in-house visualisation software, EDSERPLO. Any data considered as suspect were flagged. Flags from the originator marking suspect data were retained during transfer.
Originator's Data Processing
Sampling Strategy
A total of 49 CTD casts were performed on FRV Alba Na Mara cruise 0710A (02 June 2010 - 22 June 2010) at Wee Bankie and Marr Bank in the North Sea. The data were collected between 12:50 hours GMT on 08 June 2010 and 11:44 hours GMT on 20 June 2010.
Water samples were collected in order to obtain independent salinity and chlorophyll measurements. The sample data were used to derive calibrations for the conductivity and fluorescence profiles collected by the CTD.
Data Processing
The raw CTD data files were processed through the SeaBird Electronics SeaSoft data processing software following standard procedures. The originators used in-house interactive visual display editing software to edit out individual spikes in the primary temperature and conductivity channels. In addition, a low-pass filter (Sy 1985) was applied to particularly noisy data. An ASCII file was generated for each CTD cast and all files from a cruise were concatenated into one ASCII file which was submitted to BODC.
Sy A., 1985. An alternative editing technique for oceanographic data. Deep Sea Research Part A: Oceanographic Research Papers, 32 (12), 1591-1599.
Field Calibrations
Independent samples, obtained from the sample bottle and spread throughout the cruise, were used to calibrate the CTD conductivity and fluoresence data. Outlying points were discarded, 48 data points were used to derive the conductivity calibration and 50 data points were used to derive the chlorophyll calibration. The sample analyses yielded a straight line conductivity calibration of the form y = mx + c, where m=1.001416 and c =-0.078684, and a straight line fluorescence calibration of the form y = mx + c, where m=0.000463 and c=0.080357.
| Parameter | Value of m (y=mx+c) | Value of c (y=mx+c) | Equation |
|---|---|---|---|
| Conductivity | 1.001416 | -0.078684 | C(cal) = 1.001416C(obs) - 0.078684 |
| Fluoresence | 0.000463 | 0.080357 | C(cal) = 0.000463C(obs) + 0.080357 |
The uncalibrated data and calibrations were submitted to BODC, who applied the appropriate corrections.
Project Information
No Project Information held for the Series
Data Activity or Cruise Information
Cruise
| Cruise Name | 0710A |
| Departure Date | 2010-06-02 |
| Arrival Date | 2010-06-22 |
| Principal Scientist(s) | Simon Greenstreet (Marine Scotland Aberdeen Marine Laboratory) |
| Ship | FRV Alba Na Mara |
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 |
