Metadata Report for BODC Series Reference Number 1167142


Metadata Summary

Data Description

Data Category Multiple data types -data buoy
Instrument Type
NameCategories
Aanderaa Oxygen Optode 3835  dissolved gas sensors
Seapoint Turbidity Meter  optical backscatter sensors
Seapoint chlorophyll fluorometer  fluorometers
LI-COR LI-192 PAR sensor  radiometers
Falmouth Scientific Instruments OEM conductivity-temperature sensor  water temperature sensor; salinity sensor
Instrument Mounting subsurface mooring
Originating Country United Kingdom
Originator Dr Naomi Greenwood
Originating Organization Centre for Environment, Fisheries and Aquaculture Science Lowestoft Laboratory
Processing Status banked
Project(s) -
 

Data Identifiers

Originator's Identifier NTHDOGGER_MAY07-SEP07_31M
BODC Series Reference 1167142
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2007-05-21 13:00
End Time (yyyy-mm-dd hh:mm) 2007-09-19 12:00
Nominal Cycle Interval 1800.0 seconds
 

Spatial Co-ordinates

Latitude 55.68333 N ( 55° 41.0' N )
Longitude 2.28000 E ( 2° 16.8' E )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor Depth 31.0 m
Maximum Sensor Depth 31.0 m
Minimum Sensor Height 49.0 m
Maximum Sensor Height 49.0 m
Sea Floor Depth 80.0 m
Sensor Distribution Fixed common depth - All sensors are grouped effectively at the same depth which is effectively fixed for the duration of the series
Sensor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum Approximate - Depth is only approximate
 

Parameters

BODC CODE Rank Units Short Title Title
AADYAA01 1 Days Date(Loch_Day) Date (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ01 1 Days Time(Day_Fract) Time (time between 00:00 UT and timestamp)
ACYCAA01 1 Dimensionless Record_No Sequence number
CPHLPR01 1 Milligrams per cubic metre chl-a_water_ISfluor Concentration of chlorophyll-a {chl-a CAS 479-61-8} per unit volume of the water body [particulate >unknown phase] by in-situ chlorophyll fluorometer
DOXYOP01 1 Micromoles per litre WC_dissO2_ISoptode Concentration of oxygen {O2 CAS 7782-44-7} per unit volume of the water body [dissolved plus reactive particulate phase] by in-situ oxygen optode
IRRDUV01 1 MicroEinsteins per square metre per second SubsurVPAR Downwelling vector irradiance as photons (PAR wavelengths) in the water body by cosine-collector radiometer
OXYTAAOP 1 Degrees Celsius O2_temp Temperature of oxygen determination by optode
PSALST01 1 Dimensionless P_sal_CTD Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm
TSEDBS01 1 Milligrams per litre TSPMO Concentration of suspended particulate material {SPM} per unit volume of the water body [particulate >unknown phase] by in-situ optical backscatter measurement
 

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


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.


Narrative Documents

Falmouth Scientific Inc. OEM CT sensor

The OEM CT sensor is designed to provide high accuracy conductivity and temperature measurements in a package that can be readily integrated into user systems. The CT sensor relies on an inductively coupled conductivity sensor, with a large inside diameter that eliminates the need for pumps. A high grade Platinum Resistance Thermometer is used to measure temperature.

Sensor specifications are given in the table below. Since 2009 this instrument has been manufactured by Teledyne RD Instruments as a Citadel CT-EK Sensor. More information about the instrument can be found on the Teledyne Citadel specification sheet .

Sensor Specifications

Instrument Parameter Small CT Cell Conductivity Large CT Cell Conductivity Temperature
Range 0 to 70 mS cm -1 0 to 70 mS cm -1 -2 to 35 degrees C
Accuracy ±0.020 mS cm -1 ±0.010 mS cm -1 ±0.050 degrees C
Stability ±0.005 mS cm -1 mo -1 ±0.003 mS cm -1 ±0.005 degrees C mo -1
Response 20 cm @ 1 m s -1 15 cm @ 1 m s -1 20 seconds internal, 1 second external

Power Input 50 mW @ 6 VDC, voltage range 6 - 14 VDC
Logic 2 0 - 5 VDC control lines
Output Impedance 500 ohms

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 mm 3
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

Aanderaa Oxygen Optodes models 3835, 4130, 4175, 3830, 3930 and 3975

The Aanderaa Oxygen Optode is based on the ability of selected substances to act as dynamic fluorescence quenchers. The fluorescent indicator is a special platinum porphyrin complex embedded in a gas permeable foil that is exposed to the surrounding water.

A black optical isolation coating protects the complex from sunlight and fluorescent particles in the water. This sensing foil is attached to a window providing optical access for the measuring system from inside a watertight titanium housing.

The foil is excited by modulated blue light, and the phase of a returned red light is measured. By linearizing and temperature compensating, with an incorporated temperature sensor, the absolute O 2 concentration can be determined. According to the manufacturer, the lifetime-based luminescence quenching principle offers the following advantages over electro-chemical sensors:

The 3835, 4130 and 4175 models are designed to operate down to 300 m, while there are two versions of the 3830, 3930 and 3975 models, designed to operate down to 2000 m and 6000 m, respectively. The sensors fit directly on to the top end-plate of Recording Current Meter RCM 9, and other Aanderaa instruments. Sensor specifications may be viewed via the following links: Aanderaa Oxygen Optodes 3835/4130/4175 and Aanderaa Oxygen Optodes 3830/3930/3975 .

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 and LI-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 .

Data processing by originator

Instruments and methods for all North Dogger SmartBuoy deployments are described by Greenwood et al. (2010). The thermocline-depth rig on the SmartBuoy mooring was equipped with the following instruments:

Instrument Serial number Depth Parameters
Seapoint chlorophyll fluorometer 2757 31 m Chlorophyll fluorescence
Aanderaa Optode 497 31 m Oxygen concentration, cell temperature
LiCor PAR Sensor 32 31 m PAR
FSI CT module 1993 31 m Salinity
Seapoint optical back scatter meter 10152 31 m Suspended particulates

In situ measurements

In situ sensors were mounted at 31 m depth on the mooring. A solid state data logger (ESM-2) designed and built by Centre for Environment, Fisheries and Aquaculture Science (Cefas, UK) was used for data acquisition and sensor control. Measurements were recorded at a frequency of 1 Hz for turbidity, chlorophyll fluorescence and temperature and conductivity from FSI sensors and at 5 Hz for Aanderaa optode and Aanderaa conductivity sensors, with a burst frequency of 2 per hour and a burst duration of between 5 and 10 min depending on the length of mooring deployment.

The in situ chorophyll, oxygen, salinity and suspended particulates data were bench calibrated.

Discrete sample collection and analysis

Discrete samples for calibration were collected by CTD rosette sampler, during visits to the mooring. Data from CTD samples have not been merged into the mooring data set.

References

Greenwood N., Parker E.R., Ferrnand L., Sivyer D.B., Weston K., Painting S.J., Kröger S., Forster R.M., Lees H.E., Mills D.K., Laane R.W.P.M., 2010. Detection of low bottom water oxygen concentrations in the North Sea; implications for monitoring and assessment of ecosystem health. Biogeosciences, 7, 1357-1373.

Processing by BODC

The processed and quality-controlled data were supplied to BODC in a bulk, ASCII format file. Accompanying files provided instrument metadata. The data were converted into BODC's standard format, with one file for each rig deployment. The data were visually screened, taking into account comparisons between related parameters, and the environmental context. No major data issues were identified, but there may be some gaps in the data series, due to instrument failures.


Project Information


No Project Information held for the Series

Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2007-05-21
End Date (yyyy-mm-dd) 2007-09-19
Organization Undertaking ActivityCentre for Environment, Fisheries and Aquaculture Science Lowestoft Laboratory
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierNDOGGER_MAY07_SEP07
Platform Categorysubsurface mooring

No Document Information Held for the Series

Other Series linked to this Data Activity - 1167130

Cruise

Cruise Name 10/07
Departure Date 2007-05-16
Arrival Date 2007-05-23
Principal Scientist(s)David Brian Sivyer (Centre for Environment, Fisheries and Aquaculture Science Lowestoft Laboratory)
Ship RV Cefas Endeavour

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NameCefas North Dogger
CategoryOffshore location
Latitude55° 40.27' N
Longitude2° 17.88' E
Water depth below MSL80.0 m

Cefas North Dogger SmartBuoy mooring site

Cefas maintained a SmartBuoy mooring site at the north of Dogger Bank, 55°40.27'N, 2°17.88'E, in approximately 80 m of water, from 24/02/2007 to 15/09/2008.

BODC image

Normally two sensor suites were deployed on the mooring during each deployment: one near-surface (about 1 m); and one at thermocline depth (25 m or 31 m).

The near-surface frame was typically equipped as follows:

Instrument Description
NAS-3X in situ nutrient analyser Hourly in situ measurements of nitrate/nitrate concentration
WMS-2 water sampler Daily water samples for laboratory analysis of nutrient concentrations.
Fluorometer 30-minute measurements of chlorophyll fluorescence.
PAR sensors 30-minute measurements of Photosynthetically Active Radiation (PAR). Often sensors were mounted at two or three depths to give near-surface profiles indicating light attenuance.
Optical backscatter 30-minute measurements of suspended particulate concentrations
Conductivity cell 30-minute measurements of conductivity and salinity
Temperature probe 30-minute measurements of water temperature

The mid-tether frame was typically equipped as follows:

Instrument Description
Optode In situ oxygen sensor. 30-minute measurements of oxygen concentration.
Fluorometer 30-minute measurements of chlorophyll fluorescence.
PAR sensors 30-minute measurements of Photosynthetically Active Radiation (PAR) at one depth
Optical backscatter 30-minute measurements of suspended particulate concentrations
Conductivity cell 30-minute measurements of conductivity and salinity
Temperature probe 30-minute measurements of water temperature

The SmartBuoy mooring was first deployed on Cefas Endeavour cruise 3/07. Data were relayed to shore every two hours. The mooring was deployed for several months at a time, after which it was serviced, sensors replaced or repositioned, samples recovered, and then it would be re-deployed. In total, there were seven individual deployments at the North Dogger site:

Deployment Recovery Notes
Date Cruise Date Cruise
25/02/2007 3/07 23/04/2007 8/07 Sensors at 1 m and 25 m
23/04/2007 8/07 21/05/2007 10/07 Sensors at 1 m only
21/05/2007 10/07 19/09/2007 17/07 Sensors at 1 m and 31 m
19/09/2007 17/07 31/10/2007 19/07 Sensors at 1 m and 31 m
31/10/2007 19/07 20/01/2008 1/08 Sensors at 1 m and 31 m
20/01/2008 1/08 28/04/2008 8/08 Sensors at 1 m and 31 m
28/04/2008 8/08 14/09/2008 16/08 Sensors at 1 m and 31 m

SmartBuoy deployments at the North Dogger site were funded by Marine Ecosystem Connections: essential indicators of healthy, productive and biologically diverse seas, a project funded by the UK Government's Department for Environment, Food and Rural Affairs (Defra project code ME3205).

Other Series linked to this Fixed Station for this cruise - 1167130

Other Cruises linked to this Fixed Station (with the number of series) - 1/08 (2) 17/07 (2) 19/07 (2) 3/07 (2) 8/07 (2) 8/08 (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