Metadata Report for BODC Series Reference Number 279066

• 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

Problem Reports

The data are derived from instruments that were laboratory calibrated but not recalibrated using in-situ sample data, resulting in data of variable quality.

The data originators believe the temperatures to be reasonable but believe the salinity data to be of a quality too poor to be of value to physical oceanographic studies.

Checks by BODC showed deep water salinity data to be approximately 0.16 ppt lower than other cruises from the region and to be approximately 0.17 ppt lower than the climatological mean for the area.

Data Access Policy

Open 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.

If the Information Provider does not provide a specific attribution statement, or if you are using Information from several Information Providers and multiple attributions are not practical in your product or application, you may consider using the following:

"Contains public sector information licensed under the Open Government Licence v1.0."

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.

Further details can be found in the specification sheet.

RRS John Biscoe Cruise 10 CTD Data Documentation

Introduction

Documentation for the CTD data collected on RRS John Biscoe Cruise 10 (11 Dec 1989 - 21 Mar 1990) by the British Antarctic Survey, Cambridge, U.K., under the direction of J. Priddle

Data Collection

The instrument used was a Neil Brown Instruments System Mark IIIB CTD. Observed parameters were pressure, temperature and conductivity. All sensors were calibrated before and after the cruise. Up to 12 water bottles were mounted on a Rosette sampler and 4 pairs of reversing thermometers were attached. Water bottles were triggered on the downcast at 10m and at the bottom of the cast, the remainder being fired on the upcast (mainly for chemical samples). Data were collected on the downcast.

Calibration

Reversing thermometers were calibrated at the Deacon Laboratory of the Institute of Oceanographic Sciences. The pressure sensor was compared with a Bourdon gauge which had been calibrated at the National Physical Laboratory. The accuracy of the temperature data is thought to be ± 0.01°C.

Data Processing

Calibrations were applied and the data despiked by rejecting data values outside of predetermined tolerances. Data values were then averaged to provide data at 1 decibar intervals.

Data Quality

The deep water salinity data from the CTD have been compared with other measurements made in this region and also with the Levitus Atlas. They are approximately 0.16 ppt lower than data collected on various cruises including Discovery II (1929-31) and about 0.17 ppt lower than the Levitus Atlas salinities.

Reference

Levitus, S. 1982.
Climatological Atlas of the World Ocean. NOAA Professional Paper No. 13. US Government Printing Office. 173pp

Project Information

No Project Information held for the Series

Data Activity or Cruise Information

Cruise

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:

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle: