Metadata Report for BODC Series Reference Number 911843


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
NameCategories
Sea-Bird SBE 19plus SEACAT CTD  CTD; water temperature sensor; salinity sensor
Chelsea Technologies Group 2-pi PAR irradiance sensor  radiometers
Chelsea Instruments MINITracka II fluorometer  fluorometers
WETLabs C-Star transmissometer  transmissometers
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Dr James Fishwick
Originating Organization Plymouth Marine Laboratory
Processing Status banked
Project(s) Oceans 2025 Theme 10 SO10:WCO
 

Data Identifiers

Originator's Identifier 090723_E1
BODC Series Reference 911843
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2009-07-23 10:30
End Time (yyyy-mm-dd hh:mm) 2009-07-23 10:42
Nominal Cycle Interval 0.25 metres
 

Spatial Co-ordinates

Latitude 50.03400 N ( 50° 2.0' N )
Longitude 4.36200 W ( 4° 21.7' W )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor Depth 2.0 m
Maximum Sensor Depth 59.5 m
Minimum Sensor Height 15.5 m
Maximum Sensor Height 73.0 m
Sea Floor Depth 75.0 m
Sensor Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum Chart reference - Depth extracted from available chart
 

Parameters

BODC CODE Rank Units Title
ACYCAA01 1 Dimensionless Sequence number
DEPHPR01 1 Metres Depth below surface of the water body by profiling pressure sensor and converted to seawater depth using UNESCO algorithm
FVLTZZ01 1 Volts Instrument output (voltage) by in-situ chlorophyll fluorometer
IRRDPP01 1 MicroEinsteins per square metre per second Downwelling 2-pi scalar irradiance as photons (PAR wavelengths) in the water body by 2-pi scalar radiometer
POPTDR01 1 Percent Transmittance (red light wavelength) per 25cm of the water body by 25cm path length red light transmissometer
PRESPR01 1 Decibars Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level
PSALST01 1 Dimensionless Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm
SIGTPR01 1 Kilograms per cubic metre Sigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm
TEMPST01 1 Degrees Celsius Temperature of the water body by CTD or STD
 

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 Quality Document

Temperature, salinity and sigma-theta:

The profiles appear good. Only a few large isolated spikes were flagged as suspect by BODC. Users should be aware that a number of casts from these series displayed stronger variability in the suface layer.

Fluorometer voltage:

The profile trends match well with the transmissometer trends (high fluorometer voltages corresponding to low transmission). Since this is a voltage there are no comments on the absolute values. There is natural variability in the profile but nothing considered suspect that required flagging.

Transmission:

The profile trends match well with the fluorometer voltage trends (high fluorometer voltages corresponding to low transmission). Values do not exceed 100%. There is natural variability in the profile but nothing considered suspect that required flagging.

Downwelling PAR irradiance:

The trend is consistent with what would be expected for each profile. Noise in the surface bins can be due to changing cloud cover. There is natural variability in the profiles but nothing considered suspect that required flagging.


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

Instrument description

These data are collected using a CTD rig on the R/V Plymouth Quest. The CTD frame houses the following instruments:

Make Model Serial number
Sea-Bird SBE19plus 5216
Chelsea Technologies PAR sensor 07-6346-001
Chelsea Technologies MiniTracka II 07-6310-003
WetLabs C-Star (red) 25cm path length CST-1038PR

Sea-Bird SBE 19 and SBE 19plus SEACAT Profiler CTDs

The SBE 19 SEACAT Profiler is a self-contained, battery powered, pumped CTD system designed to measure conductivity, temperature, and pressure in marine or fresh water environments to depths of 10,500 meters. It was replaced by the SBE 19plus model in 2001. An updated version of this instrument is the SBE 19plus V2, which incorporates an electronics upgrade and additional features, with six differentially amplified A/D input channels, one RS-232 data input channel, and 64 MB FLASH memory.

The standard CTD unit comes with a plastic housing (rated to 600 m), although this can be replaced by titanium housing for depths up to 7000 m. It is typically used for CTD profiling although a conversion kit is available for mooring deployments. The CTD can also be attached to an SBE 36 CTD Deck Unit and Power/Data Interface Module (PDIM) for real-time operation on single-core armored cable up to 10,000 m.

Specifications

Parameter SBE 19 SBE 19plus
Temperature

Range: -5 to +35 °C

Accuracy: 0.01 °C

Resolution: 0.001 °C

Calibration: +1 to +32 °C*

Range: -5 to +35 °C

Accuracy: 0.005 °C

Resolution: 0.0001 °C

Calibration: +1 to +32 °C*

Conductivity

Range: 0 to 7 S m-1 (0 to 70 mmho cm-1)

Accuracy: 0.001 S m-1

Resolution: 0.0001 S m-1

Calibration: 0 to 7 S m-1. Physical calibration over the range 1.4 - 6 S m-1*

Range: 0 to 9 Sm-1

Accuracy: 0.0005

Resolution: 0.00005 (most oceanic waters, resolves 0.4 ppm in salinity); 0.00007 (high salinity waters, resolves 0.4 ppm in salinity); 0.00001 (fresh waters, resolves 0.1 ppm in salinity)

Calibration: 0 to 9 S m-1. Physical calibration over the range 1.4 - 6 S m-1*

Strain gauge pressure sensor

Range: 0 to100, 150, 300, 500, 1000, 1500, 3000, 5000, 10000 or 15000 psia

Accuracy: 0.25% of full scale range (100 - 1500 psia); 0.15% of full scale range (3000 - 15000 psia)

Resolution: 0.015% of full scale

Calibration: 0 to full scale in 20% steps

Range: 0 to 20, 100, 350, 1000, 2000, 3500 or 7000 m

Accuracy: 0.1% of full scale range

Resolution: 0.002% of full scale range

Calibration: ambient pressure to full scale range in 5 steps

*Measurements outside this range may be at slightly reduced accuracy due to extrapolation errors.

Options and accessories

Additional sensors can be attached to the CTD, including:

The standard SBE 5M pump may be replaced by an SBE 5P (plastic housing) or 5T (titanium housing) pump for use with dissolved oxygen and/or other pumped sensors. Further details can be found in the manufacturer's SBE 19plus V2 instrument specification or theSBE 19 andSBE 19 plus user guides.

Chelsea Instruments MINItracka Fluorometer

The MINItracka Fluorometer is an in-situ optical sensor that uses a single high intensity LED light source and, according to the manufacturer, is designed to enhance rejection of ambient daylight. The fluorometer provides a linear response between chlorophyll concentration and fluorometer voltage.

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

Sensor Specifications

  Chlorophyll-a Chlorophyll-a Rhodamine Amido Rhodamine Fluorescein
Excitation wavelengths 430/30 nm 470/30 nm 470/30 nm 425/30 nm 480/80 nm
Emission wavelength 685/30 nm 685/30 nm 590/45 nm 550/30 nm 530/30 nm
Concentration range 0.03-100 µg l-1 0.03-100 µg l-1 0.03-100 µg l-1 0.04-200 µg l-1 0.03-100 µg l-1
Resolution 0.01 µg l-1 0.01 µg l-1 0.01 µg l-1 0.025 µg l-1 0.01 µg l-1
Calibration standard Chlorophyll-a in acetone Chlorophyll-a in acetone      
  Nephelometer Phycoerythrin Phycocyanin
Excitation wavelengths 470/30 nm 530/30 nm 590/35nm
Emission wavelength 470/30 nm 580/30 nm 645/35 nm
Concentration range 0.04-100 FTU 0.03-100 µg l-1 0.03-100 µg l-1
Resolution 0.01 FTU 0.01 µg l-1 0.01 µg l-1
Mechanical   Electrical  
Body Size 149 mm long x 70 mm dia Input Voltage 7 to 40 VDC
Weight in Air 0.7 Kg Output Voltage 0 to 4 VDC (linear)
Weight in Water 0.15 Kg Power requirements 0.7 W typical
Depth Rating 600 m Signal : Noise 10,000 : 1 @ full scale

Chelsea Technologies Photosynthetically Active Radiation (PAR) Irradiance Sensor

This sensor was originally designed to assist the study of marine photosynthesis. With the use of logarithmic amplication, the sensor covers a range of 6 orders of magnitude, which avoids setting up the sensor range for the expected signal level for different ambient conditions.

The sensor consists of a hollow PTFE 2-pi collector supported by a clear acetal dome diverting light to a filter and photodiode from which a cosine response is obtained. The sensor can be used in moorings, profiling or deployed in towed vehicles and can measure both upwelling and downwelling light.

Specifications

Operation depth 1000 m
Range 2000 to 0.002 µE m-2 s-1
Angular Detection Range ± 130° from normal incidence
Relative Spectral Sensitivity

flat to ± 3% from 450 to 700 nm

down 8% of 400 nm and 36% at 350 nm

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

WETLabs C-Star transmissometer

This instrument is designed to measure beam transmittance by submersion or with an optional flow tube for pumped applications. It can be used in profiles, moorings or as part of an underway system.

Two models are available, a 25 cm pathlength, which can be built in aluminum or co-polymer, and a 10 cm pathlength with a plastic housing. Both have an analog output, but a digital model is also available.

This instrument has been updated to provide a high resolution RS232 data output, while maintaining the same design and characteristics.

Specifications

Pathlength 10 or 25 cm
Wavelength 370, 470, 530 or 660 nm
Bandwidth

~ 20 nm for wavelengths of 470, 530 and 660 nm

~ 10 to 12 nm for a wavelength of 370 nm

Temperature error 0.02 % full scale °C-1
Temperature range 0 to 30°C
Rated depth

600 m (plastic housing)

6000 m (aluminum housing)

Further details are available in the manufacturer's specification sheet or user guide.

Data Processing

Originator's Sampling Strategy

These data were collected using a CTD rig deployed from PML research vessels.

Originator's Processing

The raw CTD data were processed using the Sea-Bird software and binned to 0.25 m. The data were provided in tab delimited format.

BODC post-processing and screening

Reformatting

The data were converted from tab delimited format into BODC internal format using BODC transfer function 401. During transfer the depth variable was converted to pressure using the routine 'sw_pres', a part of the Seawater toolbox, this used the method of Fofonoff and Millard Jr. (1983) using inputs of depth and latitude. The density parameter was not transferred by BODC as this is generated to a standard algorithm during BODC transfer.

The measured variables were mapped to BODC parameter codes shown in the table below:

Originator's Parameter Name Units Description BODC parameter code Units Comments
Temp Deg C Temperature of the water column TEMPST01 Deg C -
Fluor volts Raw fluorometer voltage FVLTZZ01 volts -
Depth m Depth of the water column DEPHPR01 m -
Density kg m-3 Density of the water column by unknown algorithm - - Channel not transferred as generated during BODC transfer
Sal - Salinity of the water column PSALST01 - -
Xmiss % Transmittance POPTDR01 % -
PAR µE m-2s-1 Downwelling PAR irradiance IRRDPP01 µE m-2s-1 -
- - Pressure PRESPR01 dbar Calculated by BODC from depth and latitude
- - Sigma-theta SIGTPR01 kg m-3 Generated by BODC using Fofonoff and Millard (1983) algorithm with parameters PRESPR01, TEMPST01 and PSALST01.

Screening

Reformatted CTD data were transferred onto a graphics work station for visualisation using the in-house editor EDSERPLO. No data values were edited or deleted. Flagging was achieved by modification of the associated BODC quality control flag for suspect or null values.

Banking

The profiles were banked to the National Oceanographic Database (NODB) following BODC procedures.

References

Fofonoff, N.P. and Millard, R.C., 1983. Algorithms for computations of fundamental properties of seawater. UNESCO Technical Papers in Marine Science No. 44, 53pp.


Project Information

Oceans 2025 Theme 10, Sustained Observation Activity 10: The Western Channel Observatory (WCO)

The Western Channel Observatory will study the regional effects of ecosystem variability in the Western English Channel, in the context of global climate change. There is a long history of in situ observation at several sites (by the MBA for over 100 years and PML since the 1980s) that have been brought together to form the basis of the Western Channel Observatory; these observations include hydrography, nutrients, phytoplankton, zooplankton, demersal and pelagic fish and benthic measurements. It is upon these long-term time series that the WCO aims to continue building in order to investigate the current state of the ecosystem, how the ecosystem has changed and how the interactions of climate and fishing affect the ecosystem? The WCO provides an opportunity to combine modelling and Earth Observation infrastructure along with in situ data collection to demonstrate and validate short term forecasts of coastal phytoplankton and nutrient dynamics, as well as develop, calibrate and validate Earth Observation algorithms for bio-optical data.

The specific objectives are:

The work of the observatory will link to other parts of Theme 10 through the Continuous Plankton Recorder (CPR) routes that cover the Western English Channel (SO15) and by relevant ship-of-opportunity transects (SO8).

More detailed information on this Work Package is available at pages 28 - 31 of the official Oceans 2025 Theme 10 document: Oceans 2025 Theme 10

Weblink: http://www.oceans2025.org/


Data Activity or Cruise Information

Cruise

Cruise Name PQ090723
Departure Date 2009-07-23
Arrival Date 2009-07-23
Principal Scientist(s)Tim Smyth (Plymouth Marine Laboratory)
Ship RV Plymouth Quest

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NameWestern Channel Observatory E1
CategoryCoastal location
Latitude50° 2.00' N
Longitude4° 22.00' W
Water depth below MSL75.0 m

Western Channel Observatory station E1

The Western Channel Observatory (WCO) is situated in the Western English Channel and comprises of sustained long-term observations at a number of stations.

Station E1 is located south-west of Plymouth at 50° 2.00' N, 4° 22.00' W.

More information can be found on the Western Channel Observatory website.

Other Cruises linked to this Fixed Station (with the number of series) - D366 (D367) (2) MS070911 (1) MS071101 (1) PML020626 (1) PML020717 (1) PML020814 (1) PML021002 (1) PML021031 (1) PML021213 (1) PML030124 (1) PML030213 (1) PML030321 (1) PML030423 (1) PML030514 (1) PML030604 (1) PML030611 (1) PML030618 (1) PML030625 (1) PML030702 (1) PML030709 (1) PML030806 (1) PML030909 (1) PML040803 (1) PML040826 (1) PML041102 (1) PML041208 (1) PML050202 (1) PML050308 (1) PML050330 (1) PML050511 (1) PML050608 (1) PML050620 (1) PML050713 (1) PML050810 (1) PML050831 (1) PML050914 (1) PML050928 (1) PML051118 (1) PML060118 (1) PML060208 (1) PML060301 (1) PML060315 (1) PML061010 (1) PML061101 (1) PML070206 (1) PML070313 (1) PQ070417 (1) PQ070501 (1) PQ070605 (1) PQ070703 (1) PQ070731 (1) PQ080415 (1) PQ080429 (1) PQ080513 (1) PQ080520 (1) PQ080603 (1) PQ080617 (1) PQ080715 (1) PQ080822 (1) PQ080916 (1) PQ081008 (1) PQ081022 (1) PQ081104 (1) PQ081211 (1) PQ090107 (1) PQ090127 (1) PQ090211 (1) PQ090226 (1) PQ090311 (1) PQ090401 (1) PQ090415 (1) PQ090528 (1) PQ090609 (1) PQ090623 (1) PQ090921 (1) PQ090930 (1) PQ091013 (1) PQ100127 (1) PQ100317 (1) PQ100428 (1) PQ100511 (1) PQ100617 (1) PQ100628 (1) PQ100720 (1) PQ100817 (1) PQ100901 (1) PQ100921 (1) PQ101014 (1) PQ101115 (1) PQ101214 (1) PQ110118 (1) PQ110308 (1) PQ110321 (1) PQ110407 (1) PQ110419 (1) PQ110517 (1) PQ110602 (1) PQ110628 (1) PQ110714 (1) PQ110809 (1) PQ110823 (1) PQ110922 (1) PQ111028 (1) PQ111107 (1) PQ111122 (1) PQ120113 (1) PQ120123 (1) PQ120228 (1) PQ120314 (1) PQ120427 (1) PQ120516 (1) PQ120612 (1) PQ120626 (1) PQ120710 (1) PQ120724 (1) PQ120808 (1) PQ120823 (1) PQ120904 (1) PQ120919 (1) PQ121009 (1) PQ121023 (1) PQ121106 (1) PQ121129 (1) PQ121211 (1) PQ130123 (1) PQ130212 (1) PQ130227 (1) PQ130320 (1) PQ130423 (1) PQ130501 (1) PQ130516 (1) PQ130604 (1) PQ130618 (1) PQ130702 (1) PQ130716 (1) PQ130807 (1) PQ130820 (1) PQ130903 (1) PQ130924 (1) PQ131015 (1) PQ131112 (1) PQ131126 (1) SQ020516 (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