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Metadata Report for BODC Series Reference Number 1196005


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
NameCategories
Conductivity, temperature and depth package  CTD; water temperature sensor; salinity sensor
Instrument Mounting research vessel
Originating Country United Kingdom
Originator Dr Carol Pudsey
Originating Organization British Antarctic Survey
Processing Status QC in progress
Online delivery of data Download not available
Project(s) Marine Geophysics Scotia, Bellingshausen
 

Data Identifiers

Originator's Identifier CTD16_MODIFIED
BODC Series Reference 1196005
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1988-02-06 05:50
End Time (yyyy-mm-dd hh:mm) 1988-02-06 09:10
Nominal Cycle Interval 1.0 seconds
 

Spatial Co-ordinates

Latitude 63.33333 S ( 63° 20.0' S )
Longitude 42.17667 W ( 42° 10.6' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth 0.36 m
Maximum Sensor or Sampling Depth 3840.66 m
Minimum Sensor or Sampling Height -30.65 m
Maximum Sensor or Sampling Height 3809.64 m
Sea Floor Depth 3810.0 m
Sea Floor Depth Source CRREP
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 Unspecified -
 

Parameters

No Parameters for BODC Reference Number = 1196005

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

No Problem Report Found in the Database

Data Quality Report

Several series exhibit jumps in pressure, all instances and channels where the pressure drops to -3.0 were flagged M.

M flags were also applied to all channels when a spike in temperature was identified or when the temperature dropped to 0°C as data were also considered unrealistic.

Upcast data were sent for series 1196029 and 1196091.


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

BAS Marine Geophysics cruise D172 BODC data processing

The files were processed and calibrated at the British Antarctic Survey and were sent to BODC in excel format. Originator's variables include: press, temp, pottemp, sal, sigmat, trans and for some files, press/5, ptemp/5 and trans/5. Not all variables were transferred as there was no information on how they were obtained or their units.

The files were converted to BODC internal format (QXF) using established procedures, and included matching the originator's variables to the appropriate BODC parameter codes. No processing was carried out at BODC.

The following table shows how the variables within the originator's files were mapped to :

Originator's Parameter Name Units Description BODC Parameter Code Units Comments
press dbar Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level PRESPR01 dbar -
temp °C Temperature of the water body by CTD and verification against independent measurements TEMPCC01 °C Data verified against independent measurements
sal - Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm and calibration against independent measurements PSALCC01 - Data calibrated against independent measurements
- - Sigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm SIGTPR01 kg m-3 Derived during transfer
- - Potential temperature of the water body by computation using UNESCO 1983 algorithm POTMCV01 °C Derived during transfer

Field Calibrations

The salinity data were calibrated against independent measurements. The calculated CTD salinities were higher than autosal salinities by as much as 0.23 ppt. The independent temperature measurements performed with reversing thermometers showed that the CTD sensor was high by about 0.008 to 0.014°C.

BAS Marine Geophysics cruise D172 CTD originator's data processing

Sampling Strategy

A total of 16 CTD profiles were performed during the cruise. Data from each cast were logged independently on the BBC micro and ABC computer system. The problems with negative temperatures and pressures were solved by modifying the programs whilst on board.

The water bottles were removed from the CTD as soon as it was on deck and stored in the lab where sampling was performed. Samples were collected for suspended particulate matter studies, salinity calibration and oxygen isotope measurements.

The comparison between the reversing thermometer and the CTD sensor on casts 9 and 20 showed an agreement within 0.02°C for bottom temperatures.

The CTD unit was attached to a carousel with 12 bottles. The CTD sensors were pressure, conductivity, temperature and transmissivity. There was a reversing thermometer attached on the rosette, on casts 9 and 20, which provided independent measurements.


Project Information

Marine Geophysics- Scotia and Bellingshausen

Introduction

Marine geoscience in the Scotia and Bellingshausen Seas was one of the main research interests for British Antarctic Survey (BAS). The investigations were carried out by a group of scientists based at the University of Birmingham, which was absorbed by BAS in the mid- 1980's.

The different survey methods included, amongt others, multichannel and single channel seismic reflection, deeptow boomers, GLORIA (Geological Long Range Inclined Asdic) side-scan sonar and HAWAII-MR1 (HIGP Acoustic Wide_Angle Imaging Instrument) swath bathymetry and side-scan sonar.

This project was funded by BAS and most of the surveys were also carried out by this institution.

Scientific Objectives

This project was carried out in order to gain a better understanding of the Southern Ocean's:

  • Tectonic history
  • Active tectonic processes
  • Paleoceanography
  • Stratigraphy
  • Ice dynamics during glacial intervals

Data Availability

Data sets collected during this project are available to the academic community.


Data Activity or Cruise Information

Cruise

Cruise Name D172
Departure Date 1987-12-17
Arrival Date 1988-03-30
Principal Scientist(s)Peter F Barker (British Antarctic Survey)
Ship RRS Discovery

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
Q value below limit of quantification