Metadata Report for BODC Series Reference Number 80599

• 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

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

Bissett-Berman 9060 Salinity Temperature and Depth

The B-B 9060 STD measured salinity, temperature and depth and whose analogue output was in graphical form. The plots created were of salinity and temperature versus depth which had to be manually digitised.

RRS Discovery Cruise 48 STD Data Documentation

Introduction

Documentation for STD data collected on RRS Discovery Cruise 48 (July - August 1972) by the Department of Oceanography, University of Liverpool, Liverpool, U.K., under the direction of P. Hughes.

Instrumentation

The instrument used was the University of Liverpool Bissett Berman Salinity-Temperature-Depth system type 9006, with a Rosette water sampler attached to the wire above it. The data output from each STD lowering and raising was automatically recorded in analogue form as plots of salinity and temperature against depth.

Sampling

The STD data were collected on a grid of 25 stations, covering an area of 25 x 25 miles with stations 5 miles apart. At each station the STD probe and the Rosette sampler were lowered to 500m, or to about 5m above the bottom where the depth was shallower. Stations were identified by their 4 digit Discovery station number. Time series measurements were taken at 2 stations. The first was at station 8050 and consisted of STD dips to 450m every hour and water sampling with Rosette sampler every 4 hours. The programme continued for 4 days. The second time series was obtained at station 8051, where STD dips were made every half hour to approximately 100m, and Rosette bottle samples were taken every 3 hours over a 2 day period. For stations 8050 and 8051 individual dips are identified by the 4 digit Discovery station number, followed by the sequence number of the dip (from 01 to 98).

Data Processing

In the near surface layers spiking due to the differing response times of the temperature and conductivity sensors created a problem in interpreting the salinity profiles. The salinity profiles recorded by the STD system were subject to spiking errors towards low salinity during lowering and towards high salinity during raising. A satisfactory method of eliminating the salinity errors was obtained by superimposing the analogue traces recorded during the lowering and the raising of the STD probe and manually bisecting the resulting envelopes of salinity and temperature. The derived profiles were then digitized at depth intervals of 3m down to a depth of 300m. Below 300m digitisation was on the basis of 2 values every 15m (i.e. 307m, 315m, 322m, 330m, 337m, etc.). The only exception to this scheme was at station 8050 where the digitisation was at 5m intervals.

Data Calibration

The absolute accuracies of the temperature and salinity measurements were checked by comparison with a series of 87 temperature measurements and 133 salinity samples obtained with reversing thermometers and water bottles over the course of the cruise. From this comparison, made at depths of 25m, 300m and 600m, a small calibration constant was derived for salinity. No correction was necessary for the temperature sensor. The maximum precision error in salinity was estimated to be generally less than ± 0.04 ppt, but as much as ± 0.07 ppt in regions of strong temperature gradient where spiking was more pronounced. The maximum precision error in temperature was estimated to be less than ± 0.05 °C. Errors introduced by digitisation were negligible, the resolutions being ± 0.01 ppt in the salinity scale and ± 0.01 °C in the temperature scale.

Reference

RRS Discovery Cruise 48, July - August 1972.
Upwelling off the coast of north-west Africa. National Institute of Oceanography Cruise Report No.53. January 1973.

Johnson, D.R., Barton, E.D., Hughes, P. and Mooers, C.N.K. 1975.
Circulation in the Canary Current upwelling region off Cabo Bojador in August 1972. Deep Sea Research Vol. 22 p 547 - 558

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: