Search the data

Metadata Report for BODC Series Reference Number 442707


Metadata Summary

Data Description

Data Category Offshore sea floor pressure series
Instrument Type
NameCategories
Aanderaa WLR 5 Water Level Recorder  sea level recorders; water temperature sensor
Instrument Mounting fixed benthic node
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 wr0445.703
BODC Series Reference 442707
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1995-08-17 14:14
End Time (yyyy-mm-dd hh:mm) 1996-01-10 07:29
Nominal Cycle Interval 900.0 seconds
 

Spatial Co-ordinates

Latitude 56.60870 N ( 56° 36.5' N )
Longitude 8.93900 W ( 8° 56.3' W )
Positional Uncertainty 0.1 to 0.5 n.miles
Minimum Sensor or Sampling Depth 133.5 m
Maximum Sensor or Sampling Depth 133.5 m
Minimum Sensor or Sampling Height 0.5 m
Maximum Sensor or Sampling Height 0.5 m
Sea Floor Depth 134.0 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)
PRSTPS011DecibarsPressure (measured variable) exerted by the water body plus atmosphere by fixed in-situ pressure sensor
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

Translation errors occur in the raw data. An attempt was made by the data originator to reconstruct corrupt records.

The data originator identified the data recorded between 22:30h on 26th September 1995 and 05:00h 27th September 1995 as "suspect".


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

Aanderaa Bottom Pressure Recorder Models 5 and 6

The water level recorder models 5 and 6 are self-contained, high precision instruments for recording of the water level by precise measurement of hydrostatic pressure. The pressure sensor consists of an oscillating quartz crystal which shifts frequency with the force applied to it. Temperature is measured by a Fenwall thermistor. Data are stored on magnetic tape

Specifications

Pressure

Oscillator Frequency 36-40 kHz
Resolution 0.001% of full scale
Integration 40 seconds

Ranges available:

WLR5 0-100psi, 0-400psi (standard), 0-900psi
WLR6 0-5000psi (deep water version)

Temperature

The thermistor is a Fenwall GB32JM19

Range -3 °C to +35 °C
Accuracy ±0.1 °C
Resolution 0.04 °C
Response Time 2 minutes

Offshore Sea Floor Pressure Data Screening Carried Out by BODC

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

Header information is inspected for:

  1. Irregularities such as suspect values.

  2. Inconsistencies between related information, for example depths of meter and sea bed; times of 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; originator's comments on meter/mooring performance, data quality and parameters measured and the parameters actually present in the data cycles. Documents are written by BODC highlighting irregularities which cannot be resolved.

Data cycles are inspected via time series plots of parameters. These plots undergo intrinsic and extrinsic screening to detect suspect values within the data cycles themselves and inconsistencies when compared with adjacent data sets. 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:

  1. Spurious data at the start or end of the record.

  2. Obvious spikes of non oceanographic origin.

  3. A sequence of constant values in consecutive data cycles.

If a large percentage of the data are affected by irregularities, deemed abnormal, then instead of flagging the individual suspect values, a caution may be documented.

Inconsistencies between the characteristics of the data set and those of its neighbours, as for example between the maximum and minimum values of the parameters (spikes excluded) are, where necessary, documented.

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.

Proudman Oceanographic Laboratory Pressure Recorder Data Processing

The data are converted to scientific units using factory calibrations. The date and time channel is adjusted to take account of the 40 second integration interval. The integrity of the time stamps is verified by tidal analysis.


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) 1995-08-17
End Date (yyyy-mm-dd) 1996-02-02
Organization Undertaking ActivityProudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierPOLRIG#703
Platform Categoryfixed benthic node

Proudman Oceanographic Laboratory Moored Instrument Rig #703

This rig was deployed as part of the LOIS Shelf-Edge Study at site N140.

Rig position: 56° 36.52'N 08° 56.34'W
Deployed: 17 Aug 1995 13:52
from RRS Challenger (cruise CH121A)
Recovered: 02 Feb 1996 14:41
onto RRS Challenger (cruise CH125A)

Instruments deployed on the rig

Height above
Sea Bed
Instrument
0.5m Aanderaa Bottom Pressure Recorder (#445)

Cruise

Cruise Name CH121A
Departure Date 1995-08-10
Arrival Date 1995-08-18
Principal Scientist(s)John H Simpson (University of Wales, Bangor School of Ocean Sciences)
Ship RRS Challenger

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NameLOIS(SES) N140
CategoryOffshore location
Latitude56° 36.30' N
Longitude8° 56.10' W
Water depth below MSL138.0 m

LOIS (SES) Mooring and CTD Site N140

Site N140 was a fixed station where moorings were deployed during the Land-Ocean Interaction Study (LOIS) Shelf Edge Study (SES). It was also one of nineteen CTD sites on repeat section N, 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 a          
BPR       a a a b      

1996

Jan Feb Mar Apr May Jun Jul Aug
CM         b b b b
BPR   c c c d d d d

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

Glossary

  • CM = Current meter (Aanderaa or S4)
  • BPR = Bottom pressure recorder

Note

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

Related Fixed Station activities are detailed in Appendix 1


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: LOIS(SES) N140

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
436173Currents -subsurface Eulerian1995-05-12 18:45:0056.6052 N, 8.9342 WRRS Charles Darwin CD93A
439287Currents -subsurface Eulerian1995-05-12 19:15:0056.6052 N, 8.9342 WRRS Charles Darwin CD93A
442652Offshore sea floor pressure series1995-05-14 11:30:2456.6087 N, 8.9392 WRRS Charles Darwin CD93A
390131CTD or STD cast1995-07-25 19:54:0056.6055 N, 8.9387 WRRS Challenger CH120
442720Offshore sea floor pressure series1996-02-02 16:00:3056.6057 N, 8.9338 WRRS Challenger CH125A
439109Currents -subsurface Eulerian1996-04-23 13:15:0056.605 N, 8.9317 WRRS Challenger CH126A
439110Currents -subsurface Eulerian1996-04-23 13:15:0056.605 N, 8.9317 WRRS Challenger CH126A
439122Currents -subsurface Eulerian1996-04-23 13:15:0056.605 N, 8.9317 WRRS Challenger CH126A
442744Offshore sea floor pressure series1996-04-23 13:30:2656.6035 N, 8.9227 WRRS Challenger CH126A