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Metadata Report for BODC Series Reference Number 1196380


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
NameCategories
Neil Brown MK3 CTD  CTD; water temperature sensor; salinity sensor; dissolved gas sensors
Unknown transmissometer  transmissometers
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 ACTD60_REFORMATTED
BODC Series Reference 1196380
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1992-02-26 22:50
End Time (yyyy-mm-dd hh:mm) 1992-02-27 01:23
Nominal Cycle Interval 1.0 seconds
 

Spatial Co-ordinates

Latitude 62.57917 S ( 62° 34.8' S )
Longitude 43.31000 W ( 43° 18.6' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth 0.0 m
Maximum Sensor or Sampling Depth 2817.0 m
Minimum Sensor or Sampling Height 25.0 m
Maximum Sensor or Sampling Height 2842.0 m
Sea Floor Depth 2842.0 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 = 1196380

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 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

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.

Pressure Temperature Conductivity
Range

6500 m

3200 m (optional)

-3 to 32°C 1 to 6.5 S cm-1
Accuracy

0.0015% FS

0.03% FS < 1 msec

0.0005°C

0.003°C < 30 msec

0.0001 S cm-1

0.0003 S cm-1 < 30 msec

Further details can be found in the specification sheet.

BAS Marine Geophysics cruise JR19920205 (JR001) BODC data processing

The casts were sent in individual spreadsheets, each containing data from one cast. 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
Pressure dbar Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level PRESPR01 dbar
Temperature - Temperature of the water body by CTD and verification against independent measurements TEMPCC01 °C
Salinity - Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm and calibration against independent measurements PSALCC01 -
Transmittance - Transmittance (unspecified wavelength) per unspecified length of the water body by transmissometer POPTZZ01 %
Beam attenuation - Attenuance (unspecified single wavelength) per unit length of the water body by transmissometer and calibration to read zero in clear water ATTNXAC9 m-1
- - Sigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm SIGTRP01 kg m-3
- - Potential temperature of the water body by computation using UNESCO 1983 algorithm POTMCV01 °C
- - Conversion factor (volume to mass) for the water body by CTD and computation of density (in-situ potential temperature surface pressure) reciprocal from pressure, temperature and salinity TOKGPR01 l kg-1

Reformatted CTD data were visualised using the in-house graphical editor EDSERPLO. M flags were applied to the following series and channels where anomalous values were identified:

Series Reference Channel Cycles
1196331 POPTZZ01 1-9
1196355 POPTZZ01 1-11
1196367 POPTZZ01 1-8
1196435 POPTZZ01 and ATTNXAC9 2-6

BAS Marine Geophysics cruise JR19920205 (JR001) CTD originator's data processing

Sampling Strategy

The casts were performed in flat conditions for the most part. The CTD was veered at 30 m min-1 for the first 200 m and 60 m min-1 thereafter. The pinger-bottom separation was monitored throughout the casts and the frame was stopped 10 m above the sea floor, except when the ship was drifting towards shallower areas or with heavy swell.

At most stations the reversing thermometers agreed with the CTD temperature values to within 0.002°C or 0.005°-0.008°C. The data was fully processed and calibrated at BAS, however no information accompanied these data.

Instrument Descriptions

CTD Unit and Auxiliary Sensors

The CTD unit consisted of a Neil Brown MkIII attached to a carousel with 12 bottles. The CTD sensors were pressure, conductivity, temperature, a transmissometer, an RVS pinger and two digital reversing thermometers.


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 JR19920205 (JR001)
Departure Date 1992-02-05
Arrival Date 1992-03-11
Principal Scientist(s)Peter F Barker (British Antarctic Survey)
Ship RRS James Clark Ross

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