Metadata Report for BODC Series Reference Number 352762
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
The CTD transmissometer was unreliable. Use the data with caution.
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
Neil Brown MK3 CTD
The Neil Brown MK3 conductivity-temperature-depth (CTD) profiler consists of an integral unit containing pressure, temperature and conductivity sensors with an optional dissolved oxygen sensor in a pressure-hardened casing. The most widely used variant in the 1980s and 1990s was the MK3B. An upgrade to this, the MK3C, was developed to meet the requirements of the WOCE project.
The MK3C includes a low hysteresis, titanium strain gauge pressure transducer. The transducer temperature is measured separately, allowing correction for the effects of temperature on pressure measurements. The MK3C conductivity cell features a free flow, internal field design that eliminates ducted pumping and is not affected by external metallic objects such as guard cages and external sensors.
Additional optional sensors include pH and a pressure-temperature fluorometer. The instrument is no longer in production, but is supported (repair and calibration) by General Oceanics.
Specifications
These specification apply to the MK3C version.
| Pressure | Temperature | Conductivity | |
| Range | 6500 m 3200 m (optional) | -3 to 32°C | 1 to 6.5 S cm-1 |
| Accuracy | 0.0015% FS 0.03% FS < 1 msec | 0.0005°C 0.003°C < 30 msec | 0.0001 S cm-1 0.0003 S cm-1 < 30 msec |
Further details can be found in the specification sheet.
RRS Charles Darwin Cruise 24 CTD Data Documentation
Introduction
Documentation for the CTD data collected on RRS Charles Darwin cruise 24 (June - July 1987) by the School of Ocean Sciences, University of Wales, Bangor, under the direction of E.D. Barton.
Warning
The transmissometer data are unreliable for this cruise, use with caution.
Instrumentation
The instrument used was a Neil Brown CTD/fluorometer and Niskin rosette sampler. The CTD functioned well through most of the cruise.
Calibration and Data Quality
The sensor performance was checked against 266 salinity determinations on water samples from various depths, but concentrated on the bottom waters and uniform surface layer, and 140 reversing thermometer observations.
Temperature
No significant offset was evident in temperature.
Salinity
CTD salinity during the first 50 stations agreed within 0.006 mean difference with bottle salinities determined on a Guildline Autosal, but an increasingly large difference became apparent during later stations. At the last five stations of the cruise differences were about 0.025, but sufficient water bottle samples were taken to allow adjustment of the CTD values. Slight leakage around the conductivity head is suspected as the cause of the drift.
Other Sensors
The transmissometer, fluorometer and CTD oxygen probe appeared to have worked well initially. However the transmissometer began behaving erratically, and the fault could not be located. Oxygen data appeared reasonable but unfortunately no facility for calibration of the sensor was available.
Project Information
No Project Information held for the Series
Data Activity or Cruise Information
Cruise
| Cruise Name | CD24 |
| Departure Date | 1987-06-15 |
| Arrival Date | 1987-07-14 |
| Principal Scientist(s) | Eric Desmond Barton (University of Wales, Bangor School of Ocean Sciences) |
| Ship | RRS Charles Darwin |
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 |
