Metadata Report for BODC Series Reference Number 1211255
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
FRV Alba na Mara 0313A, 0513A, and 0813A CTD Instrument Description
Sampling Strategy
CTD casts were carried out on cruises FRV Alba na Mara 0313A, FRV Alba na Mara 0513A, and FRV Alba na Mara 0813A using the instrumentation detailed below.
| Unit | Model | Serial # | Calibration Date (YYYY-MM-DD) |
|---|---|---|---|
| Pressure | Sea-Bird SBE 19plus V2 SEACAT CTD | 6029 | 2012-09-26 |
| Temperature | Sea-Bird SBE 19plus V2 SEACAT CTD | 6029 | 2012-09-28 |
| Conductivity | Sea-Bird SBE 19plus V2 SEACAT CTD | 6029 | 2012-09-28 |
| Fluorometer | WET Labs ECO FLNTU | 0947 | 2008-03-05 |
No changes to the CTD instrumentation were recorded during these cruises.
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.
Processing by BODC of FRV Alba na Mara cruises 0313A, 0513A, and 0813A CTD data.
The data arrived at BODC in 3 concatenated ASCII format files representing cruises FRV Scotia 0313A (34 casts), 0513A (55 casts) and 0813A (49 casts).
The concatenated files were sub-divided into individual files for each cast using BODC in house Matlab software, and then reformatted to the internal BODC format.
The following table shows how the variables within the files were mapped to appropriate BODC parameter codes:
| Originator's Variable | Units | Description | BODC Parameter Code | Units | Comment |
|---|---|---|---|---|---|
| Pressure | dbar | Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level | PRESPR01 | dbar | - |
| Temperature (edit) | Centigrade | Temperature of the water body by CTD or STD | TEMPST01 | °C | Celsius = Centigrade |
| Conductivity (edit) | mS cm-1 | Electrical conductivity of the water body by CTD | CNDCST01 | S m-1 |
Conversion of Originators units to BODC units = conductivity(edit)/10. Field samples for calibration were also taken during the cruise but not applied by the Originator. BODC has applied this calibration. |
| Fluorescence* | µg l-1 | Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate phase] by in-situ chlorophyll fluorometer. | CPHLPS01 | mg m-3 | Field samples for calibration were taken during the cruise but not applied by the Originator. BODC has applied this calibration. |
| Turbidity | NTU | Turbidity of the water body by in-situ optical backscatter measurement and laboratory calibration against formazin | TURBPR01 | NTU | - |
| - | - | Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm | PSALST01 | Dimensionless | Derived from TEMPST01 and CNDCST01 in transfer using Fofonoff and Millard (1983) method. |
| - | - | Sigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm | SIGTPR01 | kg m-3 | Derived from PSALST01, TEMPST01 and PRESPR01 in transfer using Fofonoff and Millard (1983) method. |
| Temperature (pri) | Centigrade | Unadjusted temperature data | - | - | Primary Temperature. Data were not loaded by BODC as Originator stated Temperature (edit) channel was a quality controlled version of the primary channel |
| Conductivity (pri) | mS cm-1 | Unadjusted conductivity data | - | - | Primary Conductivity. Data were not loaded by BODC as Originator stated Conductivity (edit) channel was a quality controlled version of the primary channel |
| Temperature (sec) | Centigrade | No data supplied | - | - | Secondary Temperature |
| Conductivity (sec) | mS cm-1 | No data supplied | - | - | Secondary Conductivity |
* Originators variable name is Fluorescence but BODC have identified that the data have had manufacturer's calibrations applied and are therefore chlorophyll values.
The reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag, missing data by both setting the data to an appropriate value and setting the quality control flag.
Reference
Fofonoff, P., Millard Jr, R.C., 1983. Algorithms for computation of fundamental properties of seawater.Unesco Technical Papers in Marine Sciences 44, 53 pp.
Processing by Originator of FRV Alba na Mara 0813A CTD data
Sampling Strategy
Marine Scotland preformed 49 CTD casts during cruise FRV Alba Na Mara 0813A as part of ongoing research funded by the Scottish Government and with an aim to inform the PICMATOP research project.
A Seabird CTD was deployed at stations in the Wee Bankie, Marr Bank, Stonehaven and Turbot Bank areas off the coast of eastern Scotland in the North Sea. The ship departed Fraserburgh dock on 12 June 2013 and returned to dock on 2 July 2013.
A Knudsen reversing bottle attached to a wire 1m above the CTD was used to collect all 49 water samples taken during the cruise.
Data Processing
The CTD data were processed by Marine Scotland using the Sea-Bird SeaSoft routines as recommended in the SeaSoft manual for model type Sea-Bird SBE19plus V2 SEACAT.
Pressure data were binned to 1 dbar using SeaSoft and the primary temperature and conductivity channels were adjusted to produce 'edit' channels. Marine Scotland regards the 'edit' channels as the definitive version of the data.
The adjustments consisted of a de-spiking process using Marine Scotland in-house visualisation software and, as necessary, application of a low pass filter as described in Sy (1985). The time was recorded in UTC.
Field Calibrations
Conductivity
Marine Scotland used 47 water samples collected by the Knudsen reversing bottle to generate a calibration equation as follows:
calibrated conductivity (mS cm-1) = measured conductivity x 1.001185 - 0.037173
The calibration was not applied to the data by the Originator.
Fluorescence
Marine Scotland used 49 water samples (no points discarded) collected by the Knudsen reversing bottle to generate a calibration equation as follows:
Calibrated fluorescence (µg l-1) = measured fluorescence x 0.000326 + 0.494421.
The calibration was not applied to the data by the Originator.
Reference
Sy A., 1985. An alternative editing technique for oceanographic data. Deep Sea Research, 32 (12), 1591-1599,
Project Information
No Project Information held for the Series
Data Activity or Cruise Information
Cruise
| Cruise Name | 0813A |
| Departure Date | 2013-06-13 |
| Arrival Date | 2013-07-02 |
| Principal Scientist(s) | Philip Boulcott (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 |
