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Metadata Report for BODC Series Reference Number 444100


Metadata Summary

Data Description

Data Category Currents -subsurface Eulerian
Instrument Type Paddle wheel current meter
Instrument Mounting subsurface mooring
Originating Country United Kingdom
Originator Prof Robin Pingree
Originating Organization Plymouth Marine Laboratory (now Marine Biological Association of the UK)
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) OMEX I
 

Data Identifiers

Originator's Identifier 112162c.150
BODC Series Reference 444100
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1995-09-03 17:30
End Time (yyyy-mm-dd hh:mm) 1995-10-20 05:30
Nominal Cycle Interval 3600.0 seconds
 

Spatial Co-ordinates

Latitude 49.14640 N ( 49° 8.8' N )
Longitude 10.52000 W ( 10° 31.2' W )
Positional Uncertainty 0.1 to 0.5 n.miles
Minimum Sensor or Sampling Depth 30.0 m
Maximum Sensor or Sampling Depth 30.0 m
Minimum Sensor or Sampling Height 112.0 m
Maximum Sensor or Sampling Height 112.0 m
Sea Floor Depth 142.0 m
Sea Floor Depth Source -
Sensor or Sampling Distribution Fixed common depth - All sensors are grouped effectively at the same depth which is effectively fixed for the duration of the series
Sensor or Sampling Depth Datum Sea floor reference - Depth measured as a height above sea floor but converted into a depth relative to the sea surface according to the same datum as used for sea floor depth (applicable to instrument depths not bathymetric depths)
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
 

Parameters

BODC CODERankUnitsTitle
AADYAA011DaysDate (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ011DaysTime (time between 00:00 UT and timestamp)
LCDAEL011Degrees TrueDirection (towards) of water current (Eulerian measurement) in the water body by in-situ current meter and correction to true North
LCSAEL011Centimetres per secondSpeed of water current (Eulerian measurement) in the water body by in-situ current meter
PREXPR011DecibarsPressure (measured variable) exerted by the water body by semi-fixed in-situ pressure sensor and corrected to read zero at sea level
TEMPPR011Degrees CelsiusTemperature of the water body

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

Unusually noiseless pressure signal in the period 16-22 September 1995.


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

BODC Current Meter Screening

BODC screen both the series header qualifying information and the parameter values in the data cycles themselves.

Header information is inspected for:

  • Irregularities such as unfeasible values
  • Inconsistencies between related information. For example:
    • Depths of meter and sea bed.
    • Times for mooring deployment and for start/end of data series.
    • Length of record or number of data cycles, the cycle interval, the clock error and the period over which accrued.
    • Parameters stated as measured and the parameters actually present in the data cycles.
  • Originator's comments on meter/mooring performance and data quality.

Documents are written by BODC highlighting irregularities which cannot be resolved.

Data cycles are inspected using time series plots of all parameters. Currents are additionally inspected using vector scatter plots and time series plots of North and East velocity components. These presentations undergo intrinsic and extrinsic screening to detect infeasible values within the data cycles themselves and inconsistencies as seen when comparing characteristics of adjacent data sets displaced with respect to depth, position or time. Values suspected of being of non- oceanographic origin may be tagged with the BODC flag denoting suspect value.

The following types of irregularity, each relying on visual detection in the time series plot, are amongst those which may be flagged as suspect:

  • Spurious data at the start or end of the record.
  • Obvious spikes occurring in periods free from meteorological disturbance.
  • A sequence of constant values in consecutive data cycles.

If a large percentage of the data is affected by irregularities, deemed abnormal, then instead of flagging the individual suspect values, a caution may be documented. Likewise documents will highlight irregularities seen in the current vector scatter plots such as incongruous centre holes, evidence of mooring 'knock-down', abnormal asymmetry in tidally dominated records or gaps as when a range of speeds or directions go unregistered due to meter malfunction.

The term 'knock-down' refers to the situation when the 'drag' exerted on a mooring at high current speeds may cause instruments to tilt beyond the angle at which they are intended to operate. At this point the efficiency of the current sensors to accurately record the flow is reduced.

Inconsistencies between the characteristics of the data set and those of its neighbours are sought, and where necessary, documented. This covers inconsistencies in the following:

  • Maximum and minimum values of parameters (spikes excluded).
  • The orientation and symmetry of the current vector scatter plot.
  • The direction of rotation of the current vectors.
  • The approximate amplitude and periodicity of the tidal currents.
  • The occurrence of meteorological events and, finally, for series for which no time check was possible, the phase.

This intrinsic and extrinsic screening of the parameter values seeks to confirm the qualifying information and the source laboratory's comments on the series. In screening and collating information, every care is taken to ensure that errors of BODC making are not introduced.


Project Information

Ocean Margin EXchange (OMEX) I

Introduction

OMEX was a European multidisciplinary oceanographic research project that studied and quantified the exchange processes of carbon and associated elements between the continental shelf of western Europe and the open Atlantic Ocean. The project ran in two phases known as OMEX I (1993-1996) and OMEX II - II (1997-2000), with a bridging phase OMEX II - I (1996-1997). The project was supported by the European Union under the second and third phases of its MArine Science and Technology Programme (MAST) through contracts MAS2-CT93-0069 and MAS3-CT97-0076. It was led by Professor Roland Wollast from Université Libre de Bruxelles, Belgium and involved more than 100 scientists from 10 European countries.

Scientific Objectives

The aim of the Ocean Margin EXchange (OMEX) project was to gain a better understanding of the physical, chemical and biological processes occurring at the ocean margins in order to quantify fluxes of energy and matter (carbon, nutrients and other trace elements) across this boundary. The research culminated in the development of quantitative budgets for the areas studied using an approach based on both field measurements and modeling.

OMEX I (1993-1996)

The first phase of OMEX was divided into sub-projects by discipline:

  • Physics
  • Biogeochemical Cycles
  • Biological Processes
  • Benthic Processes
  • Carbon Cycling and Biogases

This emphasises the multidisciplinary nature of the research.

The project fieldwork focussed on the region of the European Margin adjacent to the Goban Spur (off the coast of Brittany) and the shelf break off Tromsø, Norway. However, there was also data collected off the Iberian Margin and to the west of Ireland. In all a total of 57 research cruises (excluding 295 Continuous Plankton Recorder tows) were involved in the collection of OMEX I data.

Data Availability

Field data collected during OMEX I have been published by BODC as a CD-ROM product, entitled:

  • OMEX I Project Data Set (two discs)

Further descriptions of this product and order forms may be found on the BODC web site.

The data are also held in BODC's databases and subsets may be obtained by request from BODC.


Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 1995-09-03
End Date (yyyy-mm-dd) 1995-10-20
Organization Undertaking ActivityPlymouth Marine Laboratory
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierGS150
Platform Categorysubsurface mooring

Plymouth Marine Laboratory Moored Instrument Rig Number GS150 (Sept 1995)

Position 49.14640° N, 10.51998° W
Water depth 142 m
Deployed 03 Sep 1995
from RRS Discovery (DI216)
Recovered 20 Oct 1995
from ??? (trawled by fishing boat?)

The instruments were anchored by 1000 kg of chain and kept errect by a 41" diameter sub-surface buoy.

Instruments deployed on the rig

Height above
Sea Bed
Instrument
112 m Aanderaa current meter (#11216)

Cruise

Cruise Name D216
Departure Date 1995-08-26
Arrival Date 1995-09-12
Principal Scientist(s)Peter J Statham (University of Southampton Department of Oceanography)
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