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Metadata Report for BODC Series Reference Number 476095

Metadata Summary

Data Description

Data Category Fluorescence or pigments
Instrument Type
Chelsea Technologies Group Aquatracka fluorometer  fluorometers
Instrument Mounting subsurface mooring
Originating Country United Kingdom
Originator -
Originating Organization Dunstaffnage Marine Laboratory (now Scottish Association for Marine Science)
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 011C128B
BODC Series Reference 476095

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1996-04-22 17:02
End Time (yyyy-mm-dd hh:mm) 1996-07-09 14:02
Nominal Cycle Interval 3600.0 seconds

Spatial Co-ordinates

Latitude 56.70930 N ( 56° 42.6' N )
Longitude 9.40880 W ( 9° 24.5' W )
Positional Uncertainty 0.5 to 1.0 n.miles
Minimum Sensor or Sampling Depth 1463.0 m
Maximum Sensor or Sampling Depth 1463.0 m
Minimum Sensor or Sampling Height 6.0 m
Maximum Sensor or Sampling Height 6.0 m
Sea Floor Depth 1469.0 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


BODC CODERankUnitsTitle
AADYAA011DaysDate (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ011DaysTime (time between 00:00 UT and timestamp)
CPHLPR011Milligrams per cubic metreConcentration of chlorophyll-a {chl-a CAS 479-61-8} per unit volume of the water body [particulate >unknown phase] by in-situ chlorophyll fluorometer
FCNTDC011DimensionlessRaw signal (counts) of instrument output by in-situ chlorophyll fluorometer and dark current baseline correction
FCNTRW011DimensionlessRaw signal (counts) of instrument output by in-situ chlorophyll fluorometer

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

In this series the timestep at the month boundary did not increment to the following day and remained on the same day. Therefore an extra day was added to the day column at the following month boundaries.

  • 30/4/96-1/5/96
  • 31/5/96-1/6/96
  • 30/6/96-1/7/96

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

Aquatracka fluorometer

The Chelsea Instruments Aquatracka is a logarithmic response fluorometer. It uses a pulsed (5.5 Hz) xenon light source discharging between 320 and 800 nm through a blue filter with a peak transmission of 420 nm and a bandwidth at half maximum of 100 nm. A red filter with sharp cut off, 10% transmission at 664 nm and 678 nm, is used to pass chlorophyll-a fluorescence to the sample photodiode.

The instrument may be deployed either in a through-flow tank, on a CTD frame or moored with a data logging package.

Further details can be found in the manufacturer's specification sheet.

Data Processing Notes

The following calibration was applied:

Chlorophyll (mg/m3) = -0.005136 * dark corrected signal

Fluorometer Data Processing

Data Originator's Processing

The data were logged as raw counts every three minutes which were then averaged over hourly intervals. The time stamp given is the time at the end of the interval. An unusual feature of the data was that the last averaging interval of each month was two hours rather than one hour. The resulting gap in the time channel is real and not an artefact of time channel generation.

The signal (raw counts) was transformed and corrected for dark current using a reading in the dark to give a dark corrected signal.

BODC Data Processing and Quality Control

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

Header information was inspected for:

  1. Irregularities such as unfeasible values.
  2. Inconsistencies between related information. For example:
    • Depths of meter and sea bed
    • Times for mooring deployment/recovery and series start/end
    • Length of record and number of data cycles/cycle interval/clock error
    • Parameters reported in the header and the parameters actually present in the data cycles.
  3. Originator's comments on meter/mooring performance and data quality

Problem Report documents were written by BODC to highlight any problems that cannot be resolved.

Data cycles were inspected using time series plots of all parameters. Any values considered to be erroneous have either been flagged as suspect ('M') or have been documented in a Problem Report.

Project Information

Land Ocean Interaction Study (LOIS)


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)


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.


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) 1996-04-22
End Date (yyyy-mm-dd) 1996-08-02
Organization Undertaking ActivityProudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierPOLRIG#774
Platform Categorysubsurface mooring

Proudman Oceanographic Laboratory Moored Instrument Rig #774

This rig was deployed as part of the LOIS Shelf-Edge Study at site N1500.

Rig position: 56° 42.56'N 09° 24.53'W
Deployed: 22 Apr 1996 14:24
from RRS Challenger (cruise CH126A)
Recovered: 02 Aug 1996 08:37
onto RRS Challenger (cruise CH128B)

The instruments were anchored by 750kg of chain and kept erect by glass sphere packages attached at various points on the rig.

Instruments deployed on the rig

Height above
Sea Bed
500m Sediment trap (10452-1)
400m Sediment trap (10452-2)
8m Aanderaa current meter (#11820)
fitted with SeaTech transmissometer (#631)
6m Chelsea Instruments Aquatracka fluorometer (#11)

Related Data Activity activities are detailed in Appendix 1


Cruise Name CH126A
Departure Date 1996-04-11
Arrival Date 1996-04-26
Principal Scientist(s)Paul Tett (Napier University School of Life Sciences)
Ship RRS Challenger

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Station NameLOIS(SES) N1500
CategoryOffshore location
Latitude56° 43.13' N
Longitude9° 24.50' W
Water depth below MSL1500.0 m

LOIS (SES) Mooring and CTD Site N1500

Site N1500 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.


Mar Apr May Jun Jul Aug Sep Oct Nov Dec
CM a a a b b b b      
Sed a a a b b b b      


Jan Feb Mar Apr May Jun Jul Aug
CM   c c c d d d d
Fl         a a a a
Sed   c c c d d d d

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


  • CM = Current meter (Aanderaa or S4)
  • Fl = Fluorometer
  • Sed = Sediment trap


  1. Transmissometers may have been fitted to some of the current meters.
  2. 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
B nominal value
Q value below limit of quantification

Appendix 1: POLRIG#774

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
439472Currents -subsurface Eulerian1996-04-22 15:30:0056.7093 N, 9.4088 WRRS Challenger CH126A

Appendix 2: LOIS(SES) N1500

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
439214Currents -subsurface Eulerian1995-03-29 22:30:0056.7183 N, 9.4083 WRRS Charles Darwin CD91B
439202Currents -subsurface Eulerian1995-05-13 17:30:0056.7093 N, 9.4075 WRRS Charles Darwin CD93A
439392Currents -subsurface Eulerian1996-02-06 21:30:1456.7268 N, 9.413 WRRS Challenger CH125A
439472Currents -subsurface Eulerian1996-04-22 15:30:0056.7093 N, 9.4088 WRRS Challenger CH126A