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Metadata Report for BODC Series Reference Number 275495


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
NameCategories
Bissett-Bermann 9040 CTD system  CTD; water temperature sensor; salinity sensor
Instrument Mounting research vessel
Originating Country United Kingdom
Originator Dr Barry Heywood
Originating Organization British Antarctic Survey
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) BIOMASS
 

Data Identifiers

Originator's Identifier JB03/1288
BODC Series Reference 275495
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1982-02-26 23:10
End Time (yyyy-mm-dd hh:mm) 1982-02-27 01:43
Nominal Cycle Interval 1.0 decibars
 

Spatial Co-ordinates

Latitude 62.13700 S ( 62° 8.2' S )
Longitude 49.09200 W ( 49° 5.5' W )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor or Sampling Depth 6.93 m
Maximum Sensor or Sampling Depth 2246.89 m
Minimum Sensor or Sampling Height -
Maximum Sensor or Sampling Height -
Sea Floor Depth -
Sea Floor Depth Source -
Sensor or Sampling Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor or Sampling Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum -
 

Parameters

BODC CODERankUnitsTitle
ACYCAA011DimensionlessSequence number
PRESPR011DecibarsPressure (spatial coordinate) exerted by the water body by profiling pressure sensor and correction to read zero at sea level
SSALPR011Parts per thousandSalinity of the water body by conductivity cell
TEMPST011Degrees CelsiusTemperature of the water body by CTD or STD

Definition of Rank

  • Rank 1 is a one-dimensional parameter
  • Rank 2 is a two-dimensional parameter
  • Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

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.

Climatological checks indicate that the accuracy is of the order of 0.1-0.2 ppt.


Data Access Policy

Open Data supplied by Natural Environment Research Council (NERC)

You must always use the following attribution statement to acknowledge the source of the information: "Contains data supplied by Natural Environment Research Council."


Narrative Documents

Bissett-Bermann 9040 Conductivity Temperature and Depth

The basic configuration of the B-B 9040 CTD incorporates pressure, temperature and conductivity sensors which could be logged digitally. This system also made it possible to derive other parameters, such as salinity, depth and sound velocity.

The instrument was versatile and it was possible to attach a dissolved oxygen sensor or to change the CTD housing, allowing it to obtain data from deeper layers in the water column. The accuracy for salinity is ±0.02 ppt , and ±0.02°C for temperature.

This instrument was also known as the Plessey 9040.

RRS John Biscoe Cruise 03 CTD Data Documentation

Introduction

Documentation for the CTD data collected on RRS John Biscoe Cruise 03 (15 Nov 1981 - 03 Mar 1982) by the British Antarctic Survey, Cambridge, U.K., under the direction of R.B. Heywood.

Data Collection

The instrument used was a Plessey 90/40 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.

Note that it was not possible to recover and reprocess all of the data collected on this cruise to produce 1 decibar values. For those casts which were not reprocessed an earlier version of the data is held by BODC. Few processing details are available for these casts. The data are not at regular pressure intervals. Salinities from the bottle samples were determined the British Antarctic Survey using a Guildline Salinometer. Some time after these data were supplied to BODC the salinometer was found to be faulty which casts doubt on the accuracy of the salinity values.

The CTD casts that were not reprocessed were:

BODC Series
Reference No.
Originator's
Reference
BODC Series
Reference No.
Originator's
Reference
73357 JB 3/51 73658 JB 3/222
73683 JB 3/231 74348 JB 3/552
74742 JB 3/713 74778 JB 3/726
74791 JB 3/727 74809 JB 3/733
74822 JB 3/744 74846 JB 3/754
74871 JB 3/760 74895 JB 3/769
74914 JB 3/777 74938 JB 3/785
74975 JB 3/799 74999 JB 3/808
75014 JB 3/841 75051 JB 3/859
75075 JB 3/873 75099 JB 3/890
75118 JB 3/917 75143 JB 3/935
75167 JB 3/951 75180 JB 3/979
75211 JB 3/998 75235 JB 3/1014
75247 JB 3/1022 75259 JB 3/1030
75272 JB 3/1049 75296 JB 3/1060
75315 JB 3/1074 75339 JB 3/1085
75352 JB 3/1102 75376 JB 3/1111
75407 JB 3/1123 75420 JB 3/1133
75432 JB 3/1139 75456 JB 3/1162
75468 JB 3/1171 75493 JB 3/1176
75512 JB 3/1185 75536 JB 3/1196
75561 JB 3/1210 75585 JB 3/1221
75604 JB 3/1236 75641 JB 3/1254
75665 JB 3/1267 75689 JB 3/1282
75721 JB 3/1303    

Data Quality

The salinity data from the CTD have been compared with other measurements made in this region and also with the Levitus Atlas. The data which have not been reprocessed are within about 0.02 ppt of data collected on various cruises including Discovery II (1929-31) and within about 0.03 ppt of the Levitus Atlas salinities. The reprocessed salinity data are between approximately 0.1 - 0.2 ppt lower than the data which has not been reprocessed.

References

Fofonoff, N.P. and Millard Jr., R.C. 1983.
Algorithms for the computation of fundamental properties of sea water. UNESCO Technical Paper on Marine Science 44

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


Project Information

Biological Investigations of Marine Antarctic Systems and Stocks (BIOMASS)

BIOMASS was a major multi-national scientific programme for the study of the Antarctic marine ecosystem and its living resources, with emphasis on krill (Euphausia superba). It was co-sponsored by the Scientific Committee on Antarctic Research (SCAR) and the Scientific Committee on Oceanic Research (SCOR) in collaboration with the International Association for Biological Oceanography and the Advisory Committee on Marine Resources Research of the Food and Agriculture Organization of the UN.

Data were collected by 20 vessels from 12 countries during 3 field experiments. These were: the First International BIOMASS Experiment (FIBEX), November 1980 to April 1981; the Second International BIOMASS Experiment (SIBEX), Part 1, October 1983 to May 1984 and Part 2, November 1984 to April 1985.

The aim of FIBEX was to carry out a quasi-synoptic survey over a wide area of the South Atlantic, Indian Ocean and Pacific sectors of the Southern Ocean. SIBEX 1 and 2 were designed to produce a temporal sequence of observations focused on much smaller areas of the Bransfield Strait and Prydz Bay regions.

Data were collected on krill distribution from acoustic surveys and krill population structure from net-hauls. Supporting data from ichthyoplankton net-hauls, oceanographic stations (temperature, salinity, nutrients and chlorophyll-a) and observations of sea-birds at sea were also collected.

Data were collated and standardised by the BIOMASS Data Centre, at the British Antarctic Survey, Cambridge, UK. The validation and correction of the data were carried out during data analysis workshops, by the BIOMASS scientists who collected the data. The majority of the BIOMASS data have been utilized during BIOMASS workshops. However, some have not been used and must be regarded as unvalidated. The documentation accompanying the BIOMASS data set lists the known problems and validation status of the data.

At the end of the BIOMASS Programme, the BIOMASS data were made freely available to any researchers. This is on the understanding that due acknowledgement to the BIOMASS Programme and the original data collectors is made in any resulting publications.


Data Activity or Cruise Information

Cruise

Cruise Name JB03
Departure Date 1981-11-15
Arrival Date 1982-03-03
Principal Scientist(s)Barry Heywood (British Antarctic Survey)
Ship RRS John Biscoe

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