Metadata Report for BODC Series Reference Number 58312
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
There was a lack of calibration data (only 3 profiles obtained) for this cruise. This has resulted in poor quality data.
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
Guildline 8705 CTD
The 8705 CTD is a conductivity-temperature-pressure profiler designed for marine applications down to depths of 6000 m. The instrument includes an anodised aluminium tube with a steel cage to protect the temperature and conductivity sensors and a urethane cap to protect the pressure sensor.
Specifications
| Parameter | Range | Accuracy | Resolution | Stability | Response time |
|---|---|---|---|---|---|
| Pressure | 0 to 6000 dbar | ± 0.15% of full range | ± 0.01% of full range | - | < 50 ms |
| Temperature | -2 to 30 °C | ± 0.005 °C | ± 0.0005 °C | ± 0.002 °C over 30 days ± 0.0025°C over 6 months | < 50 ms |
| Conductivity * | 100 ppm to 40 ppt | ± 0.005 ppt | ± 0.001 ppt | ± 0.002 ppt over 6 months | < 50 ms |
* Conductivity specifications are given in terms of equivalent salinity
Further details can be found in the manufacturer's specification sheet.
RV Cirolana 7/1983 CTD Data Documentation
Introduction
This data document covers the CTD data collected on RV Cirolana 7/1983 (June - July 1983) by the Ministry of Agriculture, Fisheries and Food, Fisheries Laboratory, Lowestoft, Suffolk, UK, under the direction of K.J. Medler. Note that only three profiles were obtained from this cruise. As a result, the data are of poor quality due to the lack of calibration data.
Instrumentation
The instrument used was a Guildline Model 8705 Digital CTD which measured pressure, temperature and conductivity. The CTD was used alongside a General Oceanics Rosette Multisampler fitted with water bottles and was fitted with an acoustic altimeter with digital display to measure the height of the CTD above the sea bed.
Sampling Protocol
Lowering and retrieval speeds of 1 m/s were employed. Bottle sample and reversing thermometer measurements were made on ascent and sea water samples were analysed using a Guildline Autolab Salinometer. Stations 34 and 79 used a different CTD probe to that at Station 157.
Calibrations
Pressure
No pressure calibration available.
Temperature
No laboratory calibration of the temperature sensor was available. Temperatures were corrected by comparison with reversing thermometers.
Salinity
A comparison between in situ conductivity ratio of water samples (calculated using the algorithms given by Fofonoff and Millard (1983)) and measured CTD conductivity ratio enables coefficients a, b and c to be found in the equation:
CR (sample)/CR (CTD) = a * T + b * P + C
The CTD conductivity ratio is then corrected by:
CR (corrected) = CR (CTD) * (a * T + b * P + C)
Stations 34 and 79: conductivity ratio calibration using 28 water samples, all duplicates.
Station 157: conductivity ratio calibration using 20 water samples, all duplicates.
After correcting the CTD data, as described above, a comparison was made with the potential temperature (POTT) and salinity (S) relationship suggested by Saunders: (1983)
S = 34.698 + 0.098 * POTT for North Atlantic Deep Water
where POTT is less than 2.7 °C.
A comparison with Saunders POTT-S relationship highlights the poor quality of these data.
Data Processing
Data came in at 25 frames/sec and were logged on an Apricot disk, and could be plotted. At the end of each station the data were transferred to an HP1000 computer. The raw data were then averaged over 25 observations every 100 observations. This resulted in data values averaged over approximately 1db with a value every 4db.
Calibration coefficients and correction factors were applied. Derived quantities were computed from algorithms published by Fofonoff and Millard (1983).
References
Fofonoff, N.P. and Millard, R.C. Jr., (1983).
Algorithms for the computation of fundamental properties of sea water. UNESCO Technical Paper on Marine Science 44.
Saunders, P.M. (1983).
CTD data from the north east Atlantic Ocean 31° N - 46° N, July 1982. RRS Discovery Cruise 130. Institute of Oceanographic Sciences. Report No. 165.
Project Information
No Project Information held for the Series
Data Activity or Cruise Information
Cruise
| Cruise Name | CIR7/83 |
| Departure Date | 1983-06-29 |
| Arrival Date | 1983-07-28 |
| Principal Scientist(s) | Robert R Dickson (Ministry of Agriculture, Fisheries and Food Lowestoft Fisheries Laboratory) |
| Ship | RV Cirolana |
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 |
