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Metadata Report for BODC Series Reference Number 506074


Metadata Summary

Data Description

Data Category PAR radiance and irradiance
Instrument Type
NameCategories
Bangor Ocean Colour Sensor  radiometers
Instrument Mounting subsurface mooring
Originating Country United Kingdom
Originator -
Originating Organization University of Wales, Bangor School of Ocean Sciences (now Bangor University School of Ocean Sciences)
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 CS21.681
BODC Series Reference 506074
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1995-05-08 12:11
End Time (yyyy-mm-dd hh:mm) 1995-08-13 12:11
Nominal Cycle Interval 86400.0 seconds
 

Spatial Co-ordinates

Latitude 56.45470 N ( 56° 27.3' N )
Longitude 9.06520 W ( 9° 3.9' W )
Positional Uncertainty 0.1 to 0.5 n.miles
Minimum Sensor or Sampling Depth 1.0 m
Maximum Sensor or Sampling Depth 1.0 m
Minimum Sensor or Sampling Height 299.5 m
Maximum Sensor or Sampling Height 299.5 m
Sea Floor Depth 300.5 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)
CPHLUA011Milligrams per cubic metreConcentration of chlorophyll-a {chl-a CAS 479-61-8} per unit volume of the water body [particulate >unknown phase] by radiometer and computation from the ratio of upwelled irradiance at 440 and 570 nm
CPHLUB011Milligrams per cubic metreConcentration of chlorophyll-a {chl-a CAS 479-61-8} per unit volume of the water body [particulate >unknown phase] by radiometer and computation from the ratio of upwelled irradiance at 490 and 570 nm
UU01440V1MillivoltsRaw signal (voltage) of instrument output in the water body by cosine-collector upwelling 440nm radiometer
UU01490V1MillivoltsRaw signal (voltage) of instrument output in the water body by cosine-collector upwelling 490nm radiometer
UU01570V1MillivoltsRaw signal (voltage) of instrument output in the water body by cosine-collector upwelling 570nm radiometer
UU01670V1MillivoltsRaw signal (voltage) of instrument output in the water body by cosine-collector upwelling 670nm radiometer

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

The chlorophyll values computed from the 490/570 nm spectral ratio exceed 10 mg/m3 at times and should therefore be regarded 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

UNW Ocean Colour Sensor

These ocean colour sensors measured upwelling irradiance at 440, 490, 570 and 670 nm. They were designed and built by the School of Ocean Sciences, University of Wales, Bangor.

The instruments performed a 30-second integration of upwelled irradiance every 10 or 30 minutes. The resulting data were reduced to daily average values around midday prior to submission to BODC.

The spectral response of two of the four sensors was tested at Plymouth Marine Laboratory. This showed the peak transmission wavelengths to be within 2 nm of specified values and the FWHM of each channel to be approximately 10 nm. A white perspex diffuser was fitted as a cosine- response light collector.

No absolute calibration of the sensors against a standard light source was possible and consequently the data channels are stored as raw voltages.

Estimated chlorophyll concentrations were obtained by looking at the ratios of light intensities at 440:570 nm and 490:570 nm. The conversion algorithms were obtained by empirical calibration. The colour sensor output was converted to a true irradiance ratio based on measurements of downwelling atmospheric radiation assuming a flat sky irradiance spectrum. The corrected ratios were then calibrated against extracted chlorophyll data.

Chlorophyll Calibration Details

The calibrations applied to obtain chlorophyll estimates from the spectral outputs were:

log10(chl) = -1.160 * log10(440V/570V) + log10(0.123)
log10(chl) = -1.605 * log10(490V/570V) + log10(0.334)

where:

440V = output at 440 nm
490V = output at 490 nm
570V = output at 570 nm

General 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:

  • Irregularities such as unfeasible values
  • Inconsistencies between related information, for example:
    • Times for instrument deployment and for start/end of data series
    • Length of record and the number of data cycles/cycle interval
    • Parameters expected 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 or depth 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 data values will not be altered.

The following types of irregularity, each relying on visual detection in the 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 then a Problem Report will be written rather than flagging the individual suspect values. Problem Reports are also used to highlight irregularities seen in the graphical data presentations.

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

  • Maximum and minimum values of parameters (spikes excluded).
  • The occurrence of meteorological events.

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

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) 1995-05-08
End Date (yyyy-mm-dd) 1995-08-13
Organization Undertaking ActivityProudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierPOLRIG#681
Platform Categorysubsurface mooring

Proudman Oceanographic Laboratory Moored Instrument Rig #681

This rig was deployed as part of the LOIS Shelf-Edge Study at site S300.

Rig position: 56° 27.28'N 09° 03.91'W
Deployed: 08 May 1995 12:20
from RRS Charles Darwin (cruise CD93A)
Recovered: 13 Aug 1995 18:09
onto RRS Challenger (cruise CH121A)

The instruments were anchored by a clump and suspended from a toroidal buoy on the surface.

Instruments deployed on the rig

Height above
Sea Bed
Instrument
1m WS Oceans transmissometer (#1686)
1m Colour sensor (#CS21)
3m to 43m 40m thermistor chain (#2330)

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) S300
CategoryOffshore location
Latitude56° 27.14' N
Longitude9° 4.00' W
Water depth below MSL300.0 m

LOIS (SES) Mooring and CTD Site S300

Site S300 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 b b b c   d d
TChn     a a a a b      
Tr                    
NA                    

1996

Jan Feb Mar Apr May Jun Jul Aug
CM d     e e     f
TChn       c c c c d
Tr       a a a a b
NA       a a a a  

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

Glossary

  • CM = Current meter (Aanderaa or S4)
  • TChn = Thermistor chain
  • Tr = Transmissometer
  • NA = Nutrient analyser

Note

  1. Transmissometers may have been fitted to some of the current meters.
  2. Other instruments (colour sensors) 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#681

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
439656Hydrography time series at depth1995-05-08 12:30:0056.4547 N, 9.0652 WRRS Charles Darwin CD93A

Appendix 2: LOIS(SES) S300

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
436136Currents -subsurface Eulerian1995-03-28 15:35:0056.4742 N, 9.0618 WRRS Charles Darwin CD91B
439656Hydrography time series at depth1995-05-08 12:30:0056.4547 N, 9.0652 WRRS Charles Darwin CD93A
439804Hydrography time series at depth1995-05-09 16:15:0056.4587 N, 9.0627 WRRS Charles Darwin CD93A
439700Hydrography time series at depth1995-05-09 16:30:0056.4587 N, 9.0627 WRRS Charles Darwin CD93A
439724Hydrography time series at depth1995-05-09 16:30:0056.4587 N, 9.0627 WRRS Charles Darwin CD93A
426074Currents -subsurface Eulerian1995-05-09 16:32:3056.4587 N, 9.0627 WRRS Charles Darwin CD93A
431316Currents -subsurface Eulerian1995-05-09 16:45:0056.4587 N, 9.0627 WRRS Charles Darwin CD93A
431341Currents -subsurface Eulerian1995-05-09 16:45:0056.4587 N, 9.0627 WRRS Charles Darwin CD93A
431408Currents -subsurface Eulerian1995-05-09 16:45:0056.4587 N, 9.0627 WRRS Charles Darwin CD93A
439306Currents -subsurface Eulerian1995-05-09 16:45:0056.4587 N, 9.0627 WRRS Charles Darwin CD93A
439331Currents -subsurface Eulerian1995-05-09 16:45:0056.4587 N, 9.0627 WRRS Charles Darwin CD93A
439761Hydrography time series at depth1995-05-09 17:00:0056.4587 N, 9.0627 WRRS Charles Darwin CD93A
390260CTD or STD cast1995-07-27 22:28:0056.4582 N, 9.0683 WRRS Challenger CH120
439712Hydrography time series at depth1995-08-14 14:05:0056.458 N, 9.0632 WRRS Challenger CH121A
431353Currents -subsurface Eulerian1995-08-14 14:07:3056.458 N, 9.0632 WRRS Challenger CH121A
439318Currents -subsurface Eulerian1995-08-14 14:07:3056.458 N, 9.0632 WRRS Challenger CH121A
439343Currents -subsurface Eulerian1995-08-14 14:07:3056.458 N, 9.0632 WRRS Challenger CH121A
431328Currents -subsurface Eulerian1995-08-14 14:10:3056.458 N, 9.0632 WRRS Challenger CH121A
431421Currents -subsurface Eulerian1995-08-14 14:10:3056.458 N, 9.0632 WRRS Challenger CH121A
426086Currents -subsurface Eulerian1995-08-14 14:12:3056.458 N, 9.0632 WRRS Challenger CH121A
439736Hydrography time series at depth1995-08-14 14:25:0056.458 N, 9.0632 WRRS Challenger CH121A
439773Hydrography time series at depth1995-08-14 14:25:0056.458 N, 9.0632 WRRS Challenger CH121A
439816Hydrography time series at depth1995-08-14 14:59:3056.458 N, 9.0632 WRRS Challenger CH121A
431365Currents -subsurface Eulerian1995-09-03 11:15:0056.4588 N, 9.0622 WRRS Challenger CH121C
431433Currents -subsurface Eulerian1995-09-03 11:15:0056.4588 N, 9.0622 WRRS Challenger CH121C
439540Hydrography time series at depth1995-09-03 11:30:0056.4587 N, 9.0622 WRRS Challenger CH121C
439748Hydrography time series at depth1995-09-03 11:30:0056.4587 N, 9.0622 WRRS Challenger CH121C
438905Currents -subsurface Eulerian1995-11-27 07:45:0056.4622 N, 9.0612 WRRS Challenger CH123A
442467Hydrography time series at depth1996-04-19 12:30:0056.455 N, 9.0643 WRRS Challenger CH126A
436241Currents -subsurface Eulerian1996-04-19 12:45:0056.455 N, 9.0643 WRRS Challenger CH126A
436289Currents -subsurface Eulerian1996-04-19 12:45:0056.455 N, 9.0643 WRRS Challenger CH126A
439005Currents -subsurface Eulerian1996-04-19 12:45:0056.455 N, 9.0643 WRRS Challenger CH126A
442418Hydrography time series at depth1996-04-19 13:00:0056.455 N, 9.0643 WRRS Challenger CH126A
442455Hydrography time series at depth1996-04-19 13:00:0056.455 N, 9.0643 WRRS Challenger CH126A
439423Currents -subsurface Eulerian1996-04-19 13:30:0056.455 N, 9.0643 WRRS Challenger CH126A
436216Currents -subsurface Eulerian1996-04-19 14:15:0056.455 N, 9.0643 WRRS Challenger CH126A
496188Transmittance/attenuance, turbidity, or SPM conc.1996-04-19 14:42:0056.4615 N, 9.0602 WRRS Challenger CH126A
442572Hydrography time series at depth1996-04-19 15:00:0056.4615 N, 9.0602 WRRS Challenger CH126A
439030Currents -subsurface Eulerian1996-07-11 20:37:3056.4553 N, 9.0648 WRRS Challenger CH128A
439460Currents -subsurface Eulerian1996-07-11 20:37:3056.4553 N, 9.0648 WRRS Challenger CH128A
477295Hydrography time series at depth1996-07-11 20:40:0056.4553 N, 9.0648 WRRS Challenger CH128A
477258Hydrography time series at depth1996-07-11 20:42:0056.4553 N, 9.0648 WRRS Challenger CH128A
477314Hydrography time series at depth1996-07-11 20:42:0056.4553 N, 9.0648 WRRS Challenger CH128A
477363Hydrography time series at depth1996-07-11 20:42:0056.4553 N, 9.0648 WRRS Challenger CH128A
477271Hydrography time series at depth1996-07-11 20:44:0056.4553 N, 9.0648 WRRS Challenger CH128A
477326Hydrography time series at depth1996-07-11 20:44:0056.4553 N, 9.0648 WRRS Challenger CH128A
477338Hydrography time series at depth1996-07-11 20:44:0056.4553 N, 9.0648 WRRS Challenger CH128A
477351Hydrography time series at depth1996-07-11 20:44:0056.4553 N, 9.0648 WRRS Challenger CH128A
477302Hydrography time series at depth1996-07-11 20:46:0056.4553 N, 9.0648 WRRS Challenger CH128A
477283Hydrography time series at depth1996-07-11 20:50:0056.4553 N, 9.0648 WRRS Challenger CH128A
442615Hydrography time series at depth1996-07-11 20:50:0356.4553 N, 9.0648 WRRS Challenger CH128A
442627Hydrography time series at depth1996-07-11 20:50:0356.4553 N, 9.0648 WRRS Challenger CH128A
438886Currents -subsurface Eulerian1996-07-11 21:02:3056.4553 N, 9.0648 WRRS Challenger CH128A
442603Hydrography time series at depth1996-07-11 21:10:0356.4553 N, 9.0648 WRRS Challenger CH128A
438898Currents -subsurface Eulerian1996-07-11 21:32:3056.4553 N, 9.0648 WRRS Challenger CH128A
438954Currents -subsurface Eulerian1996-07-11 21:32:3056.4553 N, 9.0648 WRRS Challenger CH128A