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Metadata Report for BODC Series Reference Number 749992


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
NameCategories
Seapoint Turbidity Meter  optical backscatter sensors
Seapoint chlorophyll fluorometer  fluorometers
LI-COR LI-192 PAR sensor  radiometers
Falmouth Scientific Instruments NXIC CTD Series  CTD; water temperature sensor; salinity sensor
Instrument Mounting research vessel
Originating Country United Kingdom
Originator Dr Liam Fernand
Originating Organization Centre for Environment, Fisheries and Aquaculture Science Lowestoft Laboratory
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) Cefas A1225 North Sea Dogger Bank
 

Data Identifiers

Originator's Identifier CE14/04/047
BODC Series Reference 749992
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2004-10-25 14:45
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval 1.0 decibars
 

Spatial Co-ordinates

Latitude 55.87667 N ( 55° 52.6' N )
Longitude 1.50233 W ( 1° 30.1' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth 1.0 m
Maximum Sensor or Sampling Depth 69.8 m
Minimum Sensor or Sampling Height 1.2 m
Maximum Sensor or Sampling Height 70.0 m
Sea Floor Depth 71.0 m
Sea Floor Depth Source DATAHEAD
Sensor or Sampling Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor or Sampling Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
 

Parameters

BODC CODERankUnitsTitle
ACYCAA011DimensionlessSequence number
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
FVLTWS011VoltsRaw signal (voltage) of instrument output by linear-response chlorophyll fluorometer
IRRDUV011MicroEinsteins per square metre per secondDownwelling vector irradiance as photons of electromagnetic radiation (PAR wavelengths) in the water body by cosine-collector radiometer
LVLTLD011VoltsRaw signal (voltage) of instrument output by cosine-collector downwelling PAR radiometer
NVLTSP011VoltsRaw signal (voltage) of instrument output by SeaPoint turbidity meter
POTMCV011Degrees CelsiusPotential temperature of the water body by computation using UNESCO 1983 algorithm
PPSBZZ011MetresDepth below surface of the water body by unknown instrument and correction to zero at sea level and conversion to depth using unspecified algorithm
PRESPR011DecibarsPressure (spatial coordinate) exerted by the water body by profiling pressure sensor and correction to read zero at sea level
PSALCC011DimensionlessPractical salinity of the water body by CTD and computation using UNESCO 1983 algorithm and calibration against independent measurements
SIGTEQ011Kilograms per cubic metreSigma-theta of the water body by computation from salinity and potential temperature using UNESCO algorithm
SIGTEQST1Kilograms per cubic metreSigma-T of the water body by computation from salinity and temperature using UNESCO algorithm
SVELCT011Metres per secondSound velocity in the water body by CTD and computation from temperature and salinity by unspecified algorithm
TEMPCC011Degrees CelsiusTemperature of the water body by CTD and verification against independent measurements
TSEDBSCL1Milligrams per litreConcentration of suspended particulate material {SPM} per unit volume of the water body [particulate >unknown phase] by in-situ optical backscatter measurement and calibration against sample data

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

No Problem Report Found in the Database

BODC quality report - Cruise CE14/04

During quality control checks the following data series failed speed checks, i.e. the vessel speed calculated at successive deployment events was unrealistic in comparison to the known vessel speed (15 knots). As the time and positional metadata have been extracted from the source data file headers the most likely explanation is that the values had been logged incorrectly. To address the positional errors the following edits were made (see table below). The changes are based on assessment of the metadata and visual inspection of the relative geographical locations.

BODC REF Series Identifier Change Old value New value Comment
749992 CE14/04/047 Longitude * -1 1.50233 -1.50233 Wrong side of meridian
750378 CE14/04/117 Latitude + 1 55.00317 56.00317 Latitude out of sequence with contiguous casts
750747 CE14/04/152 Latitude + 0.1 55.64067 55.74067 Estimated position (speed still 16 knots)
750563 CE14/04/133 Longitude * -1 1.58467 -1.58467 Wrong side of meridian
750760 CE14/04/154 Start time + 1 hour 13:44:00 14:44:00 Time out of sequence with contiguous deployment references

Data Access Policy

Centre for Environment, Fisheries and Aquaculture Science (Cefas) data access conditions

The Centre for Environment, Fisheries and Aquaculture Science (Cefas) is an Executive Agency of the Department of Environment, Food and Rural Affairs (Defra), formerly the Ministry of Agriculture, Fisheries and Food (MAFF). It was also known previously as the Directorate of Fisheries Research (DFR). This data policy refers to data collected by the organisation under all titles.

  • These data have no specific confidentiality restrictions for academic users. However data are restricted for commercial requests and clearance must be obtained by BODC from Cefas before they are released.
  • Users must acknowledge data sources as it is not ethical to publish data without proper attribution. Any publication or other output resulting from usage of the data should include an acknowledgement.
  • The recommended acknowledgement is: "This study uses data from the Centre for Environment, Fisheries and Aquaculture Science (Cefas), provided by the British Oceanographic Data Centre."

Narrative Documents

Falmouth Scientific NXIC CTD Series

The FSI NXIC CTD Series is a collection of rugged Conductivity-Temperature-Depth profilers that utilise the patented Non-eXternal Inductive Cell (NXIC) conductivity sensor, which was originally developed for the US Navy DT-705 Sound Velocity/Salinity sensor. The CTDs are fast sampling, fully integrated instruments with optional battery power, datalogging and external analog sensor input.

Models in the collection include the NXIC CT Bio Direct Read-500M, NXIC CTD Bio Direct Read-500M, NXIC CTD Bio Auto-500M, NXIC CTD Direct Read-500M, NXIC CTD Direct Read-700M, NXIC CTD Auto-500M, NXIC CTD Auto-700M, NXIC CTD-ADC with external sensors, and the NXIC ETSG Thermosalinograph. Parameters are measured to an accuracy ranging from 0.002-0.010 mS/cm for conductivity, 0.005 degC for temperature and 0.08% for full scale pressure. Now marketed by Teledyne RD Instruments.

Specifications

  Conductivity Temperature Pressure
Sensor type Inductive cell Thermistor Precision-machined Silicon
Range 0 to 9.0 S m-1 -5 to 45°C user specified
Accuracy ± 0.0002 S m-1 ± 0.005°C 0.08 % full scale
Stability ± 0.00005 S cm-1 month-1 0.0005°C month-1 ± 0.004 %
Resolution 0.00001 S m-1 0.001°C 0.001 % full scale
Response 5.0 cm at 1 m sec-1 flow 100 msec 25 msec

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

Seapoint Chlorophyll Fluorometer

The Seapoint Chlorophyll Fluorometer (SCF) is a low power instrument for in situ measurements of chlorophyll a. The SCF uses modulated blue LED lamps and a blue excitation filter to excite chlorophyll a. The fluorescent light emitted by the chlorophyll a passes through a red emission filter and is detected by a silicon photodiode. The low level signal is then processed using synchronous demodulation circuitry which generates an output voltage proportional to chlorophyll a concentration. The SCF may be operated with or without a pump.

Sensor specifications, current at August 2006, are given in the table below. More information can be found at the manufacturer's web site.

Sensor Specifications

Power requirements 8 - 20 VDC, 15 mA avg., 27 mA pk.
Output 0 - 5.0 VDC
Output Time Constant 0.1 sec.
Power-up transient period < 1 sec.
Excitation Wavelength 470 nm CWL, 30 nm FWHM
Emission Wavelength 685 nm CWL, 30 nm FWHM
Sensing Volume 340 mm3
Minimum Detectable Level 0.02 µg l-1

  Gain Sensitivity, V µg-1 l-1 Range, µg l-1
Sensitivity/Range 30x
10x
3x
1x
1.0
0.33
0.1
0.033
5
15
50
150

LI-COR LI-192 Underwater Quantum Sensor

The LI-192 Underwater Quantum Sensor is used to measure photosynthetic photon flux density and is cosine corrected. The sensor is often referred to as LI-192SA or LI-192SB (the LI-192SB model was superseded by LI-192SA). One of the main differences is that the LI-192SA model includes a built-in voltage output for interfacing with NexSens iSIC and SDL data loggers.

Sensor specifications, current at January 2012, are given in the table below. More information can be found in the manufacturer's LI-192SA andLI-192SB specification sheets.

Sensor Specifications

(Specifications apply to both models unless otherwise stated)

Absolute Calibration ± 5 % in air traceable to NBS.
Sensitivity Typically 3 µA per 1000 µmol s-1 m-2 for LI-192SB and 4 µA per 1000 µmol s-1 m-2 for LI-192SA in water.
Linearity Maximum deviation of 1 % up to 10,000 µmol s-1 m-2.
Stability < ± 2 % change over a 1 year period.
Response Time 10 µs.
Temperature Dependence ± 0.15 % per °C maximum.
Cosine Correction Optimized for both underwater and atmospheric use.
Azimuth < ± 1 % error over 360 ° at 45 ° elevation.
Detector High stability silicon photovoltaic detector (blue enhanced).
Sensor Housing Corrosion resistant metal with acrylic diffuser for both saltwater and freshwater applications. Waterproof to withstand 800 psi (5500 kPa) (560 meters).

Seapoint Turbidity Meter

The Seapoint Turbidity Meter detects light scattered by particles suspended in water, generating an output voltage proportional to turbidity or suspended solids. Range is selected by two digital lines which can be hard wired or microprocessor controlled, thereby choosing the appropriate range and resolution for measurement of extremely clean to very turbid waters. The offset voltage is within 1 mV of zero and requires no adjustment across gains. The optical design confines the sensing volume to within 5 cm of the sensor allowing near-bottom measurements and minimizing errant reflections in restricted spaces.

Sensor specifications, current at August 2006, are given in the table below.

Sensor Specifications

Power requirements 7 - 20 VDC, 3.5 mA avg., 6 mA pk.
Output 0 - 5.0 VDC
Output Time Constant 0.1 sec.
RMS Noise> < 1 mV
Power-up transient period < 1 sec.
Light Source Wavelength 880 nm
Sensing Distance (from windows) < 5 cm (approx.)
Linearity < 2% deviation 0 - 750 FTU

  Gain Sensitivity (mV FTU-1) Range (FTU)
Sensitivity/Range 100x
20x
5x
1x
200
40
10
2
25
125
500
**

** output is non-linear above 750 FTU.

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


Project Information

Cefas project A1225 - North Sea Dogger Bank

This project is aimed at achieving a better understanding of the dynamics of the circulation processes of the seas around the UK. In order to characterise the extent and nature of density driven and seasonal jet-like circulation which acts as a direct and rapid pathway for transport of material. This project consists of three cruises in Autumn 2004: CO13/04, CE12/04 and CE14/04 which aim to examine change over this 2 month period from the warmest, most stratified conditions through to the breakdown period.

The chosen area of interest is the Northern flank of the Dogger Bank along a line that was previously visited in June and August 1999, 2000 and in 2001. In order to identify the structure of the mixing in the bottom region, and for comparisons with models, a thermistor chain and ADCPS will be deployed for the period between the cruises as this will enable the exact timing and nature of breakdown to be indentified. As well as the thermohaline structure the phtyoplankton structure and nutrient uptake will be investigated. With regular samples taken for Isotope analysis. The project aims can be summarised as:

1. To characterise the hydrographic structure associated with the frontal regions and investigate the transport pathways. By use of towed undulating CTDs.

2. Deploy ARGOS drifting buoys to quantify the Lagrangian circulation.

3. Deploy Mooring (ADCP and thermistor chain) to study the mixing processes in the transitional region.

4. Conduct experiments for phytoplankton production both by Nitrogen uptake method and by Carbon14 labelling. (This was not conducted as permission was not obtained for licence despite many months notice).

5. Take samples for Isotope analysis.

A summary of the cruises is shown below.

Cruise Departure date Return date Numbeer of CTD casts Track charts
CO 13/04 31st Aug 2004 4th Sep 2004 11 Cruise Track
CE 12/04 30th Sep 2004 9th Oct 2004 29 Cruise Track
CE 14/04 22nd Oct 2004 1st Nov 2004 82 Cruise Track

Data Activity or Cruise Information

Cruise

Cruise Name 14/04
Departure Date 2004-10-22
Arrival Date 2004-11-01
Principal Scientist(s)Stephen Robin Dye (Centre for Environment, Fisheries and Aquaculture Science Lowestoft Laboratory)
Ship RV Cefas Endeavour

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