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Metadata Report for BODC Series Reference Number 1848686


Metadata Summary

Data Description

Data Category Water sample data
Instrument Type
NameCategories
Niskin bottle  discrete water samplers
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Dr Denise Smythe-Wright
Originating Organization Southampton Oceanography Centre (now National Oceanography Centre, Southampton)
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) UK WOCE
 

Data Identifiers

Originator's Identifier DI233_CTD_DOXY_60:CTD13457
BODC Series Reference 1848686
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1998-05-09 01:07
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 40.49994 N ( 40° 30.0' N )
Longitude 20.00117 W ( 20° 0.1' W )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor or Sampling Depth 2.4 m
Maximum Sensor or Sampling Depth 4894.9 m
Minimum Sensor or Sampling Height -
Maximum Sensor or Sampling Height -
Sea Floor Depth -
Sea Floor Depth Source -
Sensor or Sampling Distribution Unspecified -
Sensor or Sampling Depth Datum Unspecified -
Sea Floor Depth Datum Unspecified -
 

Parameters

BODC CODERankUnitsTitle
ADEPZZ011MetresDepth (spatial coordinate) relative to water surface in the water body
BOTTFLAG1Not applicableSampling process quality flag (BODC C22)
DOXYWITX1Micromoles per litreConcentration of oxygen {O2 CAS 7782-44-7} per unit volume of the water body [dissolved plus reactive particulate phase] by Winkler titration
SAMPRFNM1DimensionlessSample reference number

Definition of BOTTFLAG

BOTTFLAGDefinition
0The sampling event occurred without any incident being reported to BODC.
1The filter in an in-situ sampling pump physically ruptured during sample resulting in an unquantifiable loss of sampled material.
2Analytical evidence (e.g. surface water salinity measured on a sample collected at depth) indicates that the water sample has been contaminated by water from depths other than the depths of sampling.
3The feedback indicator on the deck unit reported that the bottle closure command had failed. General Oceanics deck units used on NERC vessels in the 80s and 90s were renowned for reporting misfires when the bottle had been closed. This flag is also suitable for when a trigger command is mistakenly sent to a bottle that has previously been fired.
4During the sampling deployment the bottle was fired in an order other than incrementing rosette position. Indicative of the potential for errors in the assignment of bottle firing depth, especially with General Oceanics rosettes.
5Water was reported to be escaping from the bottle as the rosette was being recovered.
6The bottle seals were observed to be incorrectly seated and the bottle was only part full of water on recovery.
7Either the bottle was found to contain no sample on recovery or there was no bottle fitted to the rosette position fired (but SBE35 record may exist).
8There is reason to doubt the accuracy of the sampling depth associated with the sample.
9The bottle air vent had not been closed prior to deployment giving rise to a risk of sample contamination through leakage.

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

Niskin Bottle

The Niskin bottle is a device used by oceanographers to collect subsurface seawater samples. It is a plastic bottle with caps and rubber seals at each end and is deployed with the caps held open, allowing free-flushing of the bottle as it moves through the water column.

Standard Niskin

The standard version of the bottle includes a plastic-coated metal spring or elastic cord running through the interior of the bottle that joins the two caps, and the caps are held open against the spring by plastic lanyards. When the bottle reaches the desired depth the lanyards are released by a pressure-actuated switch, command signal or messenger weight and the caps are forced shut and sealed, trapping the seawater sample.

Lever Action Niskin

The Lever Action Niskin Bottle differs from the standard version, in that the caps are held open during deployment by externally mounted stainless steel springs rather than an internal spring or cord. Lever Action Niskins are recommended for applications where a completely clear sample chamber is critical or for use in deep cold water.

Clean Sampling

A modified version of the standard Niskin bottle has been developed for clean sampling. This is teflon-coated and uses a latex cord to close the caps rather than a metal spring. The clean version of the Levered Action Niskin bottle is also teflon-coated and uses epoxy covered springs in place of the stainless steel springs. These bottles are specifically designed to minimise metal contamination when sampling trace metals.

Deployment

Bottles may be deployed singly clamped to a wire or in groups of up to 48 on a rosette. Standard bottles have a capacity between 1.7 and 30 L, while Lever Action bottles have a capacity between 1.7 and 12 L. Reversing thermometers may be attached to a spring-loaded disk that rotates through 180° on bottle closure.

D233 Discrete CTD Dissolved Oxygen Sampling Document

Originator's Protocol for Data Acquisition and Analysis

Sample collection and analysis

Discrete oxygen samples were collected from CTD Niskin bottles fired during D233. Duplicate samples (between one and four) were obtained on each cast, typically from the deepest bottles. Oxygen samples were drawn immediately after those collected for CFC analysis. Samples were obtained in clear, pre-calibrated wide-necked glass bottles using a short silicon tube attached to the Niskin. Samples were fixed immediately with precise manganese chloride and alkaline iodide additions, the sample temperature at the time of fixing being recorded using a hand held thermometer. Samples were shaken for approximately 30 seconds on deck and again once the samples had stabilised for 30 minutes in the ship's Constant Temperature Laboratory. Care was taken not to introduce bubbles to the sample at any stage, if this occurred the sample was discarded. Samples were stored underwater prior to analysis.

The samples were analysed onboard using the Winkler whole bottle titration method with amperometric endpoint detection (Culberson and Haung, 1987). The equipment used was supplied by Metrohm. The normality of the thiosulphate titrant was verified with an in-house standard prior to each analytical run and adjustments made accordingly. Blank measurements were also made and accounted for according to WOCE protocols.

A mean difference of 0.457 (+/- 0.282) µmol L-1 was found between duplicate oxygen pairs sampled on each station, once high duplicate differences had been removed from the data set.

BODC Data Processing Procedures

PSTAR-formatted CTD sample data from this cruise were supplied to BODC during December 1999. The oxygen data were extracted from these files and loaded into BODC's Oracle database. Flags were assigned if values were considered suspect.

Content of data series

Originator parameter Originator units BODC parameter code BODC units Comments
botoxy µmol L-1 DOXYWITX µmol L-1 No unit conversion necessary

References

Culberson, C. H., and Haung, S., (1987). Automated amperometric oxygen titration. Deep Sea Res., 34, 875 - 880.

Smythe-Wright, D., (1999). RRS Discovery Cruise 233, 23 APR - 01 JUN 1998. CHAOS. Cruise Report No. 24 Southampton Oceanography Centre.


Project Information

UK WOCE

The UK made a substantial contribution to the international World Ocean Circulation Experiment (WOCE) project by focusing on two important regions:

  1. Southern Ocean - links all the worlds oceans, controlling global climate.
  2. North Atlantic - directly affects the climate of Europe.

A major part of the UK effort was in the Southern Ocean and work included:

  • Two surveys, in the South Atlantic as part of the WOCE Hydrographic Programme.
  • SWINDEX, a year long study of the Antarctic Circumpolar Current (ACC) where it crosses major topography south of Africa.
  • ADOX, a study of deep water flow from the Atlantic to the Indian Ocean.
  • ACCLAIM, a study of the ACC by altimetry and island measurements.

In the North Atlantic the UK undertook:

  • NATRE, a purposeful tracer experiment to look at cross isopycnic processes.
  • CONVEX, a study of the deep ocean circulation and its changes.
  • VIVALDI, a seven year programme of seasonally repeated surveys to study the upper ocean.
  • Long-term observations of ocean climate in the North West Approaches.

Satellite ocean surface topography, temperature and wind data were merged with in situ observations and models to create a complete description of ocean circulation, eddy motion and the way the ocean is driven by the atmosphere.

The surveys were forerunners to the international Global Ocean Observing System (GOOS). GOOS was later established to monitor annual to decadal changes in ocean circulation and heat storage which are vital in the prediction of climate change.


Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 1998-05-08
End Date (yyyy-mm-dd) 1998-05-09
Organization Undertaking ActivitySouthampton Oceanography Centre (now National Oceanography Centre, Southampton)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierDI233_CTD_CTD13457
Platform Categorylowered unmanned submersible

BODC Sample Metadata Report for DI233_CTD_CTD13457

Sample reference number Nominal collection volume(l) Bottle rosette position Bottle firing sequence number Minimum pressure sampled (dbar) Maximum pressure sampled (dbar) Depth of sampling point (m) Bottle type Sample quality flag Bottle reference Comments
109744   10.00     4990.90 4992.40 4894.90 Niskin bottle No problem reported    
109745   10.00     4589.50 4591.00 4505.20 Niskin bottle No problem reported    
109746   10.00     4074.60 4076.10 4004.40 Niskin bottle No problem reported    
109747   10.00     3562.20 3563.70 3504.80 Niskin bottle No problem reported    
109748   10.00     3050.30 3051.80 3004.70 Niskin bottle No problem reported    
109749   10.00     2538.40 2539.90 2503.30 Niskin bottle No problem reported    
109750   10.00     2282.10 2283.60 2251.90 Niskin bottle No problem reported    
109751   10.00     2029.80 2031.30 2004.00 Niskin bottle No problem reported    
109752   10.00     1775.00 1776.50 1753.50 Niskin bottle No problem reported    
109753   10.00     1521.80 1523.30 1504.20 Niskin bottle No problem reported    
109754   10.00     1268.80 1270.30 1254.80 Niskin bottle No problem reported    
109755   10.00     1015.70 1017.20 1005.00 Niskin bottle No problem reported    
109756   10.00      813.40  814.90  805.20 Niskin bottle No problem reported    
109757   10.00      611.40  612.90  605.40 Niskin bottle No problem reported    
109758   10.00      409.20  410.70  405.20 Niskin bottle No problem reported    
109759   10.00      208.00  209.50  205.90 Niskin bottle No problem reported    
109760   10.00      158.00  159.50  156.30 Niskin bottle No problem reported    
109761   10.00      108.20  109.70  106.90 Niskin bottle No problem reported    
109762   10.00       82.10   83.60   81.10 Niskin bottle No problem reported    
109763   10.00       57.20   58.70   56.40 Niskin bottle No problem reported    
109764   10.00       31.70   33.20   31.10 Niskin bottle No problem reported    
109765   10.00       19.10   20.60   18.60 Niskin bottle No problem reported    
109766   10.00        2.80    4.30    2.40 Niskin bottle No problem reported    

Please note:the supplied parameters may not have been sampled from all the bottle firings described in the table above. Cross-match the Sample Reference Number above against the SAMPRFNM value in the data file to identify the relevant metadata.

Related Data Activity activities are detailed in Appendix 1

Cruise

Cruise Name D233
Departure Date 1998-04-23
Arrival Date 1998-06-01
Principal Scientist(s)Denise Smythe-Wright (Southampton Oceanography Centre)
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

Appendix 1: DI233_CTD_CTD13457

Related series for this Data Activity are presented in the table below. Further information can be found by following the appropriate links.

If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.

Series IdentifierData CategoryStart date/timeStart positionCruise
1305539Water sample data1998-05-09 01:07:0040.49994 N, 20.00117 WRRS Discovery D233