Search the data

Metadata Report for BODC Series Reference Number 426130


Metadata Summary

Data Description

Data Category Currents -subsurface Eulerian
Instrument Type
NameCategories
Interocean S4 current meter  current meters
Instrument Mounting subsurface mooring
Originating Country United Kingdom
Originator -
Originating Organization Proudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) Land Ocean Interaction Study (LOIS)
LOIS Shelf Edge Study (LOIS - SES)
 

Data Identifiers

Originator's Identifier s41265.683
BODC Series Reference 426130
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1995-05-10 13:52
End Time (yyyy-mm-dd hh:mm) 1995-08-23 04:22
Nominal Cycle Interval 600.0 seconds
 

Spatial Co-ordinates

Latitude 56.45430 N ( 56° 27.3' N )
Longitude 9.04630 W ( 9° 2.8' W )
Positional Uncertainty 0.1 to 0.5 n.miles
Minimum Sensor or Sampling Depth 28.0 m
Maximum Sensor or Sampling Depth 28.0 m
Minimum Sensor or Sampling Height 175.0 m
Maximum Sensor or Sampling Height 175.0 m
Sea Floor Depth 203.0 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

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

It is possible that the rig moved at 10:45 on May 14th 1995 as indicated by pressure sensors on the rig.


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

InterOcean Spherical Solid State Sensor Current Meter S4 series

The S4 family are self-contained current measuring sensors enclosing all necessary solid state electronics for acquiring, processing and outputting data. Data retrieval is accomplished through a serial port without opening the instrument.

The spherical shape of the S4 is a contributing factor in the rejection of the vertical components of water movement and there are no protruding parts or sensor support structures to interfere with the water flow.

The S4 measures the magnitude and direction of the horizontal current motion of the water. Water flows through the electromagnetic field created by the instrument, thereby producing a voltage which is proportional to the magnitude of the water velocity past the sensor. This voltage is then sensed by two pairs of titanium electrodes located symmetrically on the equator of the spherical housing which forms the sensor.

Manufacturer's specifications: Meter (sphere, diameter 25cm) is designed for depths down to 1000m (S4 standard: glass-filled cycloaliphalic epoxy construction with grooved surface for hydrodynamic stability) or down to 6000m (S4D, deep: annealed borosilicate glass version with smooth surface). The meter is shackled directly into the mooring cable by means of an axial titanium load bearing shaft.

Meter comprises:-

  1. Electromagnetic, 2 axis current speed sensor, range 0 to 350cm/s (standard) 0 to 50 and 0 to 100cm/s (optional), resolution 0.2cm/s (standard) 0.03cm/s (0 to 50 range) 0.06cm/s (0 to 100 range), accuracy 2 per cent reading +/- 1cm/s. The sensor responds to the component of flow normal to its vertical axis.

  2. Flux-gate magnetometer compass for heading information used to reference the current direction to magnetic north, compass range 360°, resolution 0.5°, accuracy 2°, tilt +/- 25° for specified accuracy.

  3. Temperature stable quartz oscillator clock, accuracy 12 minutes/year.

  4. Optional automatic tilt compensation i.e. the allowable tilt of the meter from the vertical at which the vertical cosine response is fully corrected, angle range +/- 45°, resolution 0.6°, accuracy (speed correction) 1 per cent (angle output) 0.25°.

  5. Optional semiconductor (thermistor or platinum) temperature sensor, range -5 to +45 °C, resolution 0.05 °C, accuracy 0.2 °C, response time at 63 per cent 1 min (1.5 sec thermistor or 60msec platinum).

  6. Optional conductive conductivity sensor, range 5 to 70mS/cm, resolution 0.1mS/cm, accuracy 0.2mS/cm (optional inductive sensor, range 1 to 70mS/cm).

  7. Optional semiconductor strain gauge pressure sensor, range 0 to 1000dBar (70M option), resolution 1dBar (4mm with 70M option), accuracy 0.25 per cent fs.

  8. Recorder, CMOS static RAM microprocessor, 64KByte (128K or 256KByte optional) performs vector averaging, burst sampling and adaptive sampling.

Available versions of the S4 are listed in the table below:

S4RT Basic S4 current meter without memory installed, for real-time monitoring applications only.
S4 The basic S4 current measuring instrument, with current speed and direction sensors and internal memory from 64K to 1 megabyte of solid-state memory.
S4DW S4 current meter directional wave measuring instrument. Includes 1 megabyte of memory, 70 meter high-resolution depth, adaptive sampling, and Lithium battery pack, standard.
S4P S4 instrument outfitted for profiling applications. Fitted with fast response Platinum temperature sensor, inductive flow- through conductivity sensor, and high-resolution depth sensor as standard. Memory size may be from 64K to 1 megabyte.
S4D Deep water S4 instrument for use to depths of 6,000 meters.
S4A Advanced current measuring instrument with large memory capacity, and dual-mode logging capability. Memory size may be 32-256 megabytes. Includes high speed binary down-loads using Zmodem protocol with 32 bit CRC error checking. Adaptive current sampling is standard on this instrument.
S4ADW Large memory capacity S4 directional wave measuring instrument. Includes 32 to 256 megabyte memory, 70 meter high-resolution depth sensor, and Lithium battery pack, standard.
S4ADW-i New generation of S4ADW directional wave measuring instrument providing internally-processed directional wave data for direct output from the instrument without the need for external analysis software. Ideal multi-purpose oceanographic instrument for integrated-system applications requiring pre-processed output directly into a datalogger, PLC, modem, or other external device without need for PC computer. Used for directional wave, current, and tide measurements, with additional parameters available. Includes long-life lithium battery, and internal memory sizes from 32MB to 256MB.
S4AP An S4A instrument outfitted for profiling applications. Fitted with fast response Platinum temperature sensor, inductive flow-through conductivity sensor, and high- resolution depth sensor, standard. Memory size may be 32-256 megabytes.
S4AD Deep water S4A instrument for use to depths of 6,000 meters. Has all the same features and options as available with the standard S4A.
S4AH Same as S4A but uses 5 Hz sampling rate instead of 2 Hz. S4AHDW, S4AHP, S4AHD are 5 Hz models of the units listed above.

Further details are available from the manufacturer's specification sheet.

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.

Additional Information

This instrument was recovered adrift after the mooring had been damaged by trawling.


Project Information

Land Ocean Interaction Study (LOIS)

Introduction

The Land Ocean Interaction Study (LOIS) was a Community Research Project of the Natural Environment Research Council (NERC). The broad aim of LOIS was to gain an understanding of, and an ability to predict, the nature of environmental change in the coastal zone around the UK through an integrated study from the river catchments through to the shelf break.

LOIS was a collaborative, multidisciplinary study undertaken by scientists from NERC research laboratories and Higher Education institutions. The LOIS project was managed from NERC's Plymouth Marine Laboratory.

The project ran for six years from April 1992 until April 1998 with a further modelling and synthesis phase beginning in April 1998 and ending in April 2000.

Project Structure

LOIS consisted of the following components:

  • River-Atmosphere-Coast Study (RACS)
    • RACS(A) - Atmospheric sub-component
    • RACS(C) - Coasts sub-component
    • RACS(R) - Rivers sub-component
    • BIOTA - Terrestrial salt marsh study
  • Land Ocean Evolution Perspective Study (LOEPS)
  • Shelf-Edge Study (SES)
  • North Sea Modelling Study (NORMS)
  • Data Management (DATA)

Marine Fieldwork

Marine field data were collected between September 1993 and September 1997 as part of RACS(C) and SES. The RACS data were collected throughout this period from the estuaries and coastal waters of the UK North Sea coast from Great Yarmouth to the Tweed. The SES data were collected between March 1995 and September 1996 from the Hebridean slope. Both the RACS and SES data sets incorporate a broad spectrum of measurements collected using moored instruments and research vessel surveys.


LOIS Shelf Edge Study (LOIS - SES)

Introduction

SES was a component of the NERC Land Ocean Interaction Study (LOIS) Community Research Programme that made intensive measurements from the shelf break in the region known as the Hebridean Slope from March 1995 to September 1996.

Scientific Rationale

SES was devoted to the study of interactions between the shelf seas and the open ocean. The specific objectives of the project were:

  • To identify the time and space scales of ocean-shelf momentum transmission and to quantify the contributions to ocean-shelf water exchange by physical processes.

  • To estimate fluxes of water, heat and certain dissolved and suspended constituents across a section of the shelf edge with special emphasis on net carbon export from, and nutrient import to, the shelf.

  • To incorporate process understanding into models and test these models by comparison with observations and provide a basis for estimation of fluxes integrated over time and the length of the shelf.

Fieldwork

The SES fieldwork was focussed on a box enclosing two sections across the shelf break at 56.4-56.5 °N and 56.6-56.7 °N. Moored instrument arrays were maintained throughout the experiment at stations with water depths ranging from 140 m to 1500 m, although there were heavy losses due to the intensive fishing activity in the area. The moorings included meteorological buoys, current meters, transmissometers, fluorometers, nutrient analysers (but these never returned any usable data), thermistor chains, colour sensors and sediment traps.

The moorings were serviced by research cruises at approximately three-monthly intervals. In addition to the mooring work this cruises undertook intensive CTD, water bottle and benthic surveys with cruise durations of up to 6 weeks (3 legs of approximately 2 weeks each).

Moored instrument activities associated with SES comprised current measurements in the North Channel in 1993 and the Tiree Passage from 1995-1996. These provided boundary conditions for SES modelling activities.

Additional data were provided through cruises undertaken by the Defence Evaluation and Research Agency (DERA) in a co-operative programme known as SESAME.


Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 1995-05-10
End Date (yyyy-mm-dd) 1995-09-09
Organization Undertaking ActivityProudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierPOLRIG#683
Platform Categorysubsurface mooring

Proudman Oceanographic Laboratory Moored Instrument Rig #683

This rig was deployed as part of the LOIS Shelf-Edge Study at site S200.

Rig position: 56° 27.26'N 09° 02.78'W
Deployed: 10 May 1995 13:48
from RRS Charles Darwin (cruise CD93A)
Recovered: 09 Sep 1995
onto DRA vessel Colonel Templer

The instruments were anchored by 1000kg of chain and kept erect by a 48" diameter buoy attached 20m below the sea surface.

Instruments deployed on the rig

Height above
Sea Bed
Instrument
175m S4 current meter (#1265)
152m Transmissometer (TRB-1 No.01)
151m Chelsea fluorometer (#14)
150m Aanderaa current meter (#6152)
149m to 109m 40m thermistor chain (#2322)
98m Aanderaa current meter (#10207)
97m to 47m 50m thermistor chain (#2323)
10m Aanderaa current meter (#11047) *
fitted with SeaTech transmissometer (#557) *
8m NAS2 nutrient analyser (#1751) *
  • Instruments marked "*" were lost, probably due to trawling.
    The remainder of the mooring was recovered adrift.
    Probably moved at 10:45 on 14/05/1995.

Related Data Activity activities are detailed in Appendix 1

Cruise

Cruise Name CD93A
Departure Date 1995-05-07
Arrival Date 1995-05-16
Principal Scientist(s)Paul Tett (University of Wales, Bangor School of Ocean Sciences)
Ship RRS Charles Darwin

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NameLOIS(SES) S200
CategoryOffshore location
Latitude56° 27.14' N
Longitude9° 2.90' W
Water depth below MSL200.0 m

LOIS (SES) Mooring and CTD Site S200

Site S200 was a fixed station where moorings were deployed during the Land-Ocean Interaction Study (LOIS) Shelf Edge Study (SES). It was also one of fourteen CTD sites on repeat section S, across the Hebridean Slope, occupied by cruises between March 1995 and September 1996.

Instrument Deployment History

The following tables summarise the instruments deployed at this site for which data may be available.

1995

Mar Apr May Jun Jul Aug Sep Oct Nov Dec
CM a b c c c c c      
ADCP           a a      
TChn a b c c c c c d d  
Tr a b c c c c c d e e
Fl a b c c c c c d e e
NA a b     c c d      

1996

Jan Feb Mar Apr May Jun Jul Aug
CM       d        
ADCP                
TChn                
Tr       f f f f  
Fl       f f f f  
NA                

Each different letter in the tables above corresponds to an individual instrument record.

Glossary

  • CM = Current meter (Aanderaa or S4)
  • BPR = Bottom pressure recorder
  • ADCP = Acoustic Doppler Current Profiler
  • TChn = Thermistor chain
  • Tr = Transmissometer
  • Fl = Fluorometer
  • NA = Nutrient analyser

Note

  1. Transmissometers may have been fitted to some of the current meters.
  2. Other instruments (colour sensors, STABLE) may have been deployed.
  3. Only periods for which useful data were returned are shown.

Related Fixed Station activities are detailed in Appendix 2


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: POLRIG#683

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
439607Hydrography time series at depth1995-05-10 14:00:0056.4543 N, 9.0463 WRRS Charles Darwin CD93A
439644Hydrography time series at depth1995-05-10 14:00:0056.4543 N, 9.0463 WRRS Charles Darwin CD93A
491891Transmittance/attenuance, turbidity, or SPM conc.1995-05-10 14:01:0056.4543 N, 9.0463 WRRS Charles Darwin CD93A
431285Currents -subsurface Eulerian1995-05-10 14:15:0056.4543 N, 9.0463 WRRS Charles Darwin CD93A
439066Currents -subsurface Eulerian1995-05-10 14:15:0056.4543 N, 9.0463 WRRS Charles Darwin CD93A
439447Currents -subsurface Eulerian1995-05-10 14:15:0056.4543 N, 9.0463 WRRS Charles Darwin CD93A

Appendix 2: LOIS(SES) S200

Related series for this Fixed Station 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
439576Hydrography time series at depth1995-03-31 20:20:0056.453 N, 9.0462 WRRS Charles Darwin CD91B
439620Hydrography time series at depth1995-03-31 20:20:0056.453 N, 9.0462 WRRS Charles Darwin CD91B
496072Transmittance/attenuance, turbidity, or SPM conc.1995-03-31 20:20:0056.453 N, 9.0462 WRRS Charles Darwin CD91B
431261Currents -subsurface Eulerian1995-03-31 20:25:0056.453 N, 9.0462 WRRS Charles Darwin CD91B
439042Currents -subsurface Eulerian1995-03-31 20:25:0056.453 N, 9.0462 WRRS Charles Darwin CD91B
439226Currents -subsurface Eulerian1995-03-31 20:25:0056.453 N, 9.0462 WRRS Charles Darwin CD91B
476199Fluorescence or pigments1995-03-31 21:02:5656.453 N, 9.0462 WRRS Charles Darwin CD91B
439588Hydrography time series at depth1995-04-17 15:30:0056.453 N, 9.0462 WRRS Charles Darwin CD92B
439632Hydrography time series at depth1995-04-17 15:30:0056.453 N, 9.0462 WRRS Charles Darwin CD92B
496084Transmittance/attenuance, turbidity, or SPM conc.1995-04-17 15:30:0056.453 N, 9.0462 WRRS Charles Darwin CD92B
431273Currents -subsurface Eulerian1995-04-17 15:35:0056.453 N, 9.0462 WRRS Charles Darwin CD92B
439054Currents -subsurface Eulerian1995-04-17 15:35:0056.453 N, 9.0462 WRRS Charles Darwin CD92B
439355Currents -subsurface Eulerian1995-04-17 15:35:0056.453 N, 9.0462 WRRS Charles Darwin CD92B
476206Fluorescence or pigments1995-04-17 16:09:2156.453 N, 9.0462 WRRS Charles Darwin CD92B
439607Hydrography time series at depth1995-05-10 14:00:0056.4543 N, 9.0463 WRRS Charles Darwin CD93A
439644Hydrography time series at depth1995-05-10 14:00:0056.4543 N, 9.0463 WRRS Charles Darwin CD93A
491891Transmittance/attenuance, turbidity, or SPM conc.1995-05-10 14:01:0056.4543 N, 9.0463 WRRS Charles Darwin CD93A
431285Currents -subsurface Eulerian1995-05-10 14:15:0056.4543 N, 9.0463 WRRS Charles Darwin CD93A
439066Currents -subsurface Eulerian1995-05-10 14:15:0056.4543 N, 9.0463 WRRS Charles Darwin CD93A
439447Currents -subsurface Eulerian1995-05-10 14:15:0056.4543 N, 9.0463 WRRS Charles Darwin CD93A
496096Transmittance/attenuance, turbidity, or SPM conc.1995-05-10 16:30:0056.4482 N, 9.0477 WRRS Charles Darwin CD93A
476102Fluorescence or pigments1995-05-10 17:02:5656.4482 N, 9.0477 WRRS Charles Darwin CD93A
439527Hydrography time series at depth1995-05-10 17:30:0056.4482 N, 9.0477 WRRS Charles Darwin CD93A
476058Fluorescence or pigments1995-07-25 12:02:5756.448 N, 9.046 WRRS Challenger CH120
390272CTD or STD cast1995-07-27 23:33:0056.4587 N, 9.05 WRRS Challenger CH120
444413Currents -subsurface Eulerian1995-08-11 05:37:0056.4458 N, 9.0465 WRRS Challenger CH121A
444185Currents -subsurface Eulerian1995-08-11 08:17:0056.4445 N, 9.0515 WRRS Challenger CH121A
439299Currents -subsurface Eulerian1995-08-11 19:17:3056.453 N, 9.0462 WRRS Challenger CH121A
496140Transmittance/attenuance, turbidity, or SPM conc.1995-08-16 08:00:0056.4477 N, 9.0473 WRRS Challenger CH121A
442363Hydrography time series at depth1995-08-16 08:30:0056.4477 N, 9.0473 WRRS Challenger CH121A
476175Fluorescence or pigments1995-08-16 09:09:2156.4477 N, 9.0473 WRRS Challenger CH121A
444425Currents -subsurface Eulerian1996-02-01 08:17:0056.4604 N, 9.0473 WRRS Challenger CH125A
436290Currents -subsurface Eulerian1996-04-24 13:45:0056.4523 N, 9.0497 WRRS Challenger CH126A
436308Currents -subsurface Eulerian1996-04-24 13:45:0056.4523 N, 9.0497 WRRS Challenger CH126A
439091Currents -subsurface Eulerian1996-04-24 13:45:0056.4523 N, 9.0497 WRRS Challenger CH126A