Metadata Report for BODC Series Reference Number 1215404
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
Sea-Bird Dissolved Oxygen Sensor SBE 43 and SBE 43F
The SBE 43 is a dissolved oxygen sensor designed for marine applications. It incorporates a high-performance Clark polarographic membrane with a pump that continuously plumbs water through it, preventing algal growth and the development of anoxic conditions when the sensor is taking measurements.
Two configurations are available: SBE 43 produces a voltage output and can be incorporated with any Sea-Bird CTD that accepts input from a 0-5 volt auxiliary sensor, while the SBE 43F produces a frequency output and can be integrated with an SBE 52-MP (Moored Profiler CTD) or used for OEM applications. The specifications below are common to both.
Specifications
| Housing | Plastic or titanium |
| Membrane | 0.5 mil- fast response, typical for profile applications 1 mil- slower response, typical for moored applications |
| Depth rating | 600 m (plastic) or 7000 m (titanium) 10500 m titanium housing available on request |
| Measurement range | 120% of surface saturation |
| Initial accuracy | 2% of saturation |
| Typical stability | 0.5% per 1000 h |
Further details can be found in the manufacturer's specification sheet.
FRV Scotia 0213S, 0313S, 0513S, 0813S, 0913S, 1113S, 1313S, 1513S, 1613S, and 1713S CTD Instrument Description
Sampling Strategy
CTD casts were carried out during the on FRV Scotia cruises 0213S, 0313S, 0513S, 0813S, 0913S, 1113S, 1313S, 1513S, 1613S, and 1713S using the instrumentation detailed below.
| FRV Scotia Cruise | CTD Unit and auxiliary sensors | Model | Serial # | Calibration Date (YYYY-MM-DD) |
|---|---|---|---|---|
| 0213S, 0313S | Pressure | Sea-Bird SBE 19plus V2 SEACAT CTD | 6028 | 2011-12-23 |
| Temperature (primary sensor) | ||||
| Conductivity (primary sensor) | ||||
| Fluorometer and scatter sensor | WET Labs ECO FLNTU | 0942 | 2012-02-23 | |
| 0813S, 0913S, 1113S | Pressure | Sea-Bird SBE 19plus V2 SEACAT CTD | 6029 | 2012-09-26 |
| Temperature (primary sensor) | ||||
| Conductivity (primary sensor) | ||||
| Fluorometer and scatter sensor | WET Labs ECO FLNTU | 0947 | 2008-03-05 | |
| 1513S, 1613S | Pressure | Sea-Bird SBE 19plus V2 SEACAT CTD | 6028 | 2013-08-07 |
| Temperature (primary sensor) | ||||
| Conductivity (primary sensor) | ||||
| Fluorometer and scatter sensor | WET Labs ECO FLNTU | 0942 | 2012-02-23 | |
| 0513S, 1313S, 1713S | Pressure | Paroscientific Digiquartz depth sensor | 64240 | 2010-08-05 |
| Temperature (Primary sensor) | Sea-Bird SBE 911plus CTD/ Sea-Bird SBE 3plus (SBE 3P) temperature sensor | 2041 | 2012-07-17 | |
| Temperature (Secondary sensor) | Sea-Bird SBE 911plus CTD/ Sea-Bird SBE 3plus (SBE 3P) temperature sensor | 2015 | 2012-07-17 | |
| Conductivity (Primary sensor) | Sea-Bird SBE 911plus CTD/ Sea-Bird SBE 4C conductivity sensor | 1615 | 2012-07-20 | |
| Conductivity (Secondary sensor) | Sea-Bird SBE 911plus CTD/ Sea-Bird SBE 4C conductivity sensor | 1669 | 2012-07-20 | |
| Fluorometer and scatter sensor | WET Labs ECO FLNTU | 2542 | 2012-01-20 | |
| Oxygen | Sea-Bird SBE 43 Dissolved Oxygen Sensor | 0504 | 2012-07-07 |
No changes to the CTD instrumentation were recorded during these cruises.
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.
Processing by BODC of FRV Scotia cruises 0213S, 0313S, 0513S, 0813S, 0913S, 1113S, 1313S, 1513S, 1613S, and 1713S CTD data.
The data arrived at BODC in 10 concatenated ASCII format files. Each file represented one of FRV Scotia cruises 0213S (56 casts), 0313S (59 casts), 0513S (102 casts), 0813S (40 casts), 0913S (84 casts), 1113S (15 casts), 1313S (62 casts), 1513S (2 casts), 1613S (25 casts), and 1713S (37 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 so no unit conversion required. |
| 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. BODC applied Originator calibration during 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. | CPHLPR01 | mg m-3 | No field calibrations supplied by the Originator. This applies to all flourescence data from cruises 0213S, 0313S, 0813S, 0913S, 1113S, 1513S, and 1613S. |
| 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. This applies to all flourescence data from cruises 0513S, 1313S, and 1713S. |
| Turbidity | NTU | Turbidity of the water body by in-situ optical backscatter measurement and laboratory calibration against formazin | TURBPR01 | NTU | No turbidity data were submitted for cruise FRV Scotia 0512S. |
| Oxygen (ml l-1) | ml l-1 | Concentration of oxygen (O2) per unit volume of the water body (dissolved phase) | DOXYZZXX | µmol l-1 | Conversion of Originators units to BODC units: oxygen (ml l-1) * 44.661. BODC applied Originator calibration during transfer. |
| - | - | Saturation of oxygen (O2) in the water body [dissolved plus reactive particulate phase] by Sea-Bird SBE 43 sensor and computation from concentration using Benson and Krause algorithm | OXYSSU01 | % | Derived from PSALST01, TEMPST01 and DOXYZZXX in transfer using Benson and Krause algorithm (1984). |
| - | - | 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). |
| - | - | 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). |
| 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 | Unadjusted temperature data | - | - | Secondary Temperature. Data were not loaded by BODC where supplied as Originator stated Temperature (edit) channel was a quality controlled version of the primary channel. |
| Conductivity (sec) | mS cm-1 | Unadjusted conductivity data | - | - | Secondary Conductivity. Data were not loaded by BODC where supplied as Originator stated Conductivity (edit) channel was a quality controlled version of the primary channel. |
| Oxygen % saturation | cm3 dm-3 | - | - | - | Oxygen saturation data supplied by Originator were derived using unknown methodology. No further processing was carried out. |
* 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 Scotia 1313S CTD data
Sampling Strategy
Marine Scotland performed 62 CTD casts during cruise FRV Scotia 1313S as part of ongoing research funded by the Scottish Government.
The ship set sail on 2 October 2013, journeying from Aberdeen to carry out CTD deployments on the JONSIS long term monitoring section, the Nolso_Flugga section, the Fair Isle- Munken section and the Cape Wrath - Faroe section, all located in the North Sea and North East Atlantic Ocean. The ship returned to dock in Aberdeen on 16 October 2013.
A SBE32 carousal was used to collect all 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 85 water samples collected by SBE32 carousal to generate a calibration equation as follows:
calibrated conductivity (mS cm-1) = measured conductivity x 0.999948 + 0.002485
The calibration was not applied to the data by the Originator.
Fluorescence
Marine Scotland used 78 water samples collected by the SBE35 carousel to generate a calibration equation as follows:
Calibrated fluorescence (µg l-1) = measured fluorescence x 0.00058 + 0.089722.
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 | 1313S |
| Departure Date | 2013-10-02 |
| Arrival Date | 2013-10-16 |
| Principal Scientist(s) | George Slesser (Marine Scotland Aberdeen Marine Laboratory) |
| Ship | FRV Scotia |
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 |
