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Metadata Report for BODC Series Reference Number 753665


Metadata Summary

Data Description

Data Category Currents -subsurface Eulerian
Instrument Type
NameCategories
Teledyne RDI 150kHz Narrowband Vessel-Mounted ADCP  current profilers
Instrument Mounting research vessel
Originating Country United Kingdom
Originator -
Originating Organization National Oceanography Centre, Southampton
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) Oceans 2025
Oceans 2025 Theme 2
Oceans 2025 Theme 2 WP2.5
 

Data Identifiers

Originator's Identifier ADP32111
BODC Series Reference 753665
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2007-08-08 11:06
End Time (yyyy-mm-dd hh:mm) 2007-08-09 11:05
Nominal Cycle Interval 120.0 seconds
 

Spatial Co-ordinates

Start Latitude 59.71667 N ( 59° 43.0' N )
End Latitude 59.88350 N ( 59° 53.0' N )
Start Longitude 20.72050 W ( 20° 43.2' W )
End Longitude 20.11090 W ( 20° 6.7' W )
Positional Uncertainty Unspecified
Minimum Sensor or Sampling Depth 11.0 m
Maximum Sensor or Sampling Depth 391.0 m
Minimum Sensor or Sampling Height -
Maximum Sensor or Sampling Height -
Sea Floor Depth -
Sea Floor Depth Source -
Sensor or Sampling Distribution Sensor fixed with measurements made at multiple depths within a fixed range (e.g. ADCP) - The sensor is at a fixed depth, but measurements are made remotely from the sensor over a range of depths (e.g. ADCP measurements)
Sensor or Sampling Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum -
 

Parameters

BODC CODERankUnitsTitle
DBINAA010MetresDepth (spatial coordinate) of ADCP bin relative to water surface {bin depth} in the water body
AADYAA011DaysDate (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ011DaysTime (time between 00:00 UT and timestamp)
ACYCAA011DimensionlessSequence number
ALATGP011DegreesLatitude north relative to WGS84 by unspecified GPS system
ALONGP011DegreesLongitude east relative to WGS84 by unspecified GPS system
APEWGP012Centimetres per secondEastward velocity of measurement platform relative to ground surface by unspecified GPS system
APNSGP012Centimetres per secondNorthward velocity of measurement platform relative to ground surface by unspecified GPS system
ASAMAP012DecibelsSignal return amplitude from the water body by moored acoustic doppler current profiler (ADCP)
LCEWAS012Centimetres per secondEastward velocity of water current (Eulerian measurement) in the water body by shipborne acoustic doppler current profiler (ADCP)
LCNSAS012Centimetres per secondNorthward velocity of water current (Eulerian measurement) in the water body by shipborne acoustic doppler current profiler (ADCP)
LERRAS012Centimetres per secondError velocity of water current in the water body by shipborne acoustic doppler current profiler (ADCP)
LREWAS012Centimetres per secondEastward velocity of water current relative to moving platform in the water body by shipborne acoustic doppler current profiler (ADCP)
LRNSAS012Centimetres per secondNorthward velocity of water current relative to moving platform in the water body by shipborne acoustic doppler current profiler (ADCP)
LRZAAS012Centimetres per secondUpward velocity of water current in the water body by shipborne acoustic doppler current profiler (ADCP)
PCGDAP012PercentAcceptable proportion of acoustic signal returns from the water body by acoustic doppler current profiler (ADCP)

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

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

Water velocities were measured using a vessel mounted Teledyne RDI 150 kHz ADCP (VMADCP). The transducer unit was installed in the hull 1.75 m to port of the keel, 33 m aft of the bow at the waterline and at an approximate depth of 5 m. Data were logged using IBM Data Acquisition Software (DAS) version 2.48 with profiler software 17.10. Position and ship velocities were derived from the Bestnav system which is an assembly of multiple GPS signals, including the gyronmea and em-log stream in order to calculate the best possible position, speed, heading, pitch and roll of the ship. Further information on VMADCP instrumentation can be found in the cruise report on p89 and on p133. Further information on navigational instrumentation can be found from p84 of the cruise report.

RD Instruments 150kHz Narrow Band Acoustic Doppler Current Profiler

Specifications

Water velocity measurements relative to the ADCP
Accuracy (long term) 0.5 % of measured velocity ± 0.5 cm/s
Statistical uncertainty for one ping (cm/s) Depth cell length of 4, 8, 16 m = 26, 13, 6.5 respectively (for horizontal velocities using the standard transducer)
Ping rate (pings per second) 2 (100 pings averaged in ADCP)
Maximum profiling range (meters) 290
Minimum range to start of first depth cell (meters) 4
Number of depth cells 8 to 128
Velocity range ± 0.01 to 9.5 m/s (horizontal)
Velocity resolution (cm/s) 0.25 or 0.125
Velocity measurements relative to the bottom and measurement of bottom depth
Accuracy 0.5% of measured velocity ± 0.5 cm/s
Statistical uncertainty of one ping (percent of measured velocity) 3.5 (for horizontal velocities using the standard transducer)
Ping rate (pings per second) 0.9 (100 pings averaged in ADCP)
Depth range 290 (the maximum depth range can be up to 1.5 times greater than specified)
Bottom depth resolution (meters) 4
Velocity range ± 0.01 to 9.5 m/s (horizontal)
Velocity resolution (cm/s) 0.25 or 0.125
Measurement of echo intensity
Accuracy (with temperature correction) Before calibration : ± 8 dB, After calibration: ± 3 dB
Statistical uncertainty for one ping Approximately ± 5 dB
Ping rate (pings per second) 2 (100 pings averaged in ADCP)
Profiling range (meters less than for water velocity measurement) 64
Number of depth cells 8 to 128
Dynamic range 80 dB
Resolution 0.45 dB typical (temperature/system dependent)
Data communication
Interface Modified RS-232/422 serial at baud rates of 300-19,200
Data format Binary (8-bit) or ASCII (76-character) lines separated by a carriage return/line feed.
Data storage capacity 2 MB (standard); expandable to 40 MB in 1 and/or 2 MB increments
Power requirements
ADCP electronics Voltage range (VDC) 6-12; Standby current (amps) 0.0002; Operate current (amps) 0.24; Peak current (amps) 0.5
transmit and EPROM recorder Voltage range (VDC) 20-40; Standby current (amps) 0.0001; Operate current (amps) 0.10; Peak current (amps) 2.0
CTD sensors Voltage range (VDC) 12-20; Standby current (amps) 0.0001; Operate current (amps) 0.022; Peak current (amps) 0.05
Temperature sensor
Accuracy ± 0.2°C
Time constant Approximately 2 minutes
Range -5° to 45°C
Resolution 0.012°C
Environmental
Operating temperature -5°C to 40°C
Humidity Must be non-condensing
Depth capability 35 meters (transducer only)
Physical characteristics
Weight in air 67.6 kg
Weight in water 25.0
Diameter 45.9 cm
Length 141.4 cm

BODC Processing

The data arrived at BODC in 23 PSTAR format files (nomenclature = adp321##.abs) representing all the data collected during the cruise. These were reformatted to the internal QXF format using BODC transfer function 389. The following table shows how the variables within the PSTAR files were mapped to appropriate BODC parameter codes:

Originator's Variable Units Description BODC Parameter Code Units Comment
time sec Time - - automatically transferred
bindepth m Bin depth relative to sea surface DBINAA01 m  
evencal cm s-1 Eastward velocity measured by ADCP (calibrated) LREWAS01 cm s-1  
nvelcal cm s-1 Northward velocity measured by ADCP (calibrated) LRNSAS01 cm s-1  
ve cm s-1 Ship's eastward velocity APEWGP01 cm s-1 derived from Bestnav data stream
vn cm s-1 Ship's northward velocity APNSGP01 cm s-1 derived from Bestnav data stream
absve cm s-1 Absolute eastward velocity of the water column by ADCP LCEWAS01 cm s-1  
absvn cm s-1 Absolute northward velocity of the water column by ADCP LCNSAS01 cm s-1  
velvert cm s-1 Upward current velocity of the water column by ADCP LRZAAS01 cm s-1  
velerr cm s-1 Current velocity error in the water column by ADCP LERRAS01 cm s-1  
ampl decibel Signal return amplitude by ADCP ASAMSP01 decibel  
good % % good by ADCP PCGDAP01 %  
a-ghdg degrees ASHTECH gyro-heading difference - - Not transferred - derived variable
lat decimal degrees Latitude north from Bestnav data stream ALATGP01 decimal degrees  
lon decimal degrees Longitude east from Bestnav data stream ALONGP01 decimal degrees  
distrun km Distance run - - Not derived - calculated from Bestnav data stream

Following the originator's advice, the reformatted data were subsequently amended by subtracting 5 m from the original bin depths (to make the first bin depth centre equal to 11 m, instead of 16 m). This was because the originator had identified a mistake in the labelling of bin depths. The adjustment did not effect the velocities measured. The data were then visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag. Missing data were marked by setting the data to an appropriate absent data value and absent data quality control flag.

Originator's Data Processing

Sampling Strategy

The VMADCP was logged and operated throughout the cruise and was configured to sample over 120 bins of 4 m depth at 120 second intervals between 25/07/2007 11:51 to 26/07/2007 08:34 and 96 bins of 4 m depth at 120 second intervals from 26/07/2007 09:00. The blank beyond transmit and pulse length were 4 m. Data were reduced to 2 minute ensembles. The instrument was operated in water tracking mode with the exception of the cruise start (between 25/07/2007 11:51 to 26/07/2007 08:34) when the ADCP was logged in bottom tracking mode to enable a calibration. Further information on sampling strategy can be found in the cruise report on p132.

Originator's Data Processing

Logged data were transferred daily (approximately) to the PSTAR processing system where resulting files were read into PSTAR format, calibrated, corrected for the ship's movement and quality controlled using NOCS-generated Unix scripts. Full processing details can be found in the cruise report from p133.

Field Calibrations

Calibration was obtained in bottom track mode with an offset angle = 0°.

    Φ (misalignment angle) = -14.4°
    A (scaling factor) = 0.9683

Further information on calibration of the VMADCP can be found on p134 of the cruise report.


Project Information

Oceans 2025 - The NERC Marine Centres' Strategic Research Programme 2007-2012

Who funds the programme?

The Natural Environment Research Council (NERC) funds the Oceans 2025 programme, which was originally planned in the context of NERC's 2002-2007 strategy and later realigned to NERC's subsequent strategy (Next Generation Science for Planet Earth; NERC 2007).

Who is involved in the programme?

The Oceans 2025 programme was designed by and is to be implemented through seven leading UK marine centres. The marine centres work together in coordination and are also supported by cooperation and input from government bodies, universities and other partners. The seven marine centres are:

  • National Oceanography Centre, Southampton (NOCS)
  • Plymouth Marine Laboratory (PML)
  • Marine Biological Association (MBA)
  • Sir Alister Hardy Foundation for Marine Science (SAHFOS)
  • Proudman Oceanographic Laboratory (POL)
  • Scottish Association for Marine Science (SAMS)
  • Sea Mammal Research Unit (SMRU)

Oceans2025 provides funding to three national marine facilities, which provide services to the wider UK marine community, in addition to the Oceans 2025 community. These facilities are:

  • British Oceanographic Data Centre (BODC), hosted at POL
  • Permanent Service for Mean Sea Level (PSMSL), hosted at POL
  • Culture Collection of Algae and Protozoa (CCAP), hosted at SAMS

The NERC-run Strategic Ocean Funding Initiative (SOFI) provides additional support to the programme by funding additional research projects and studentships that closely complement the Oceans 2025 programme, primarily through universities.

What is the programme about?

Oceans 2025 sets out to address some key challenges that face the UK as a result of a changing marine environment. The research funded through the programme sets out to increase understanding of the size, nature and impacts of these changes, with the aim to:

  • improve knowledge of how the seas behave, not just now but in the future;
  • help assess what that might mean for the Earth system and for society;
  • assist in developing sustainable solutions for the management of marine resources for future generations;
  • enhance the research capabilities and facilities available for UK marine science.

In order to address these aims there are nine science themes supported by the Oceans 2025 programme:

  • Climate, circulation and sea level (Theme 1)
  • Marine biogeochemical cycles (Theme 2)
  • Shelf and coastal processes (Theme 3)
  • Biodiversity and ecosystem functioning (Theme 4)
  • Continental margins and deep ocean (Theme 5)
  • Sustainable marine resources (Theme 6)
  • Technology development (Theme 8)
  • Next generation ocean prediction (Theme 9)
  • Integration of sustained observations in the marine environment (Theme 10)

In the original programme proposal there was a theme on health and human impacts (Theme 7). The elements of this Theme have subsequently been included in Themes 3 and 9.

When is the programme active?

The programme started in April 2007 with funding for 5 years.

Brief summary of the programme fieldwork/data

Programme fieldwork and data collection are to be achieved through:

  • physical, biological and chemical parameters sampling throughout the North and South Atlantic during collaborative research cruises aboard NERC's research vessels RRS Discovery, RRS James Cook and RRS James Clark Ross;
  • the Continuous Plankton Recorder being deployed by SAHFOS in the North Atlantic and North Pacific on 'ships of opportunity';
  • physical parameters measured and relayed in near real-time by fixed moorings and ARGO floats;
  • coastal and shelf sea observatory data (Liverpool Bay Coastal Observatory (LBCO) and Western Channel Observatory (WCO)) using the RV Prince Madog and RV Quest.

The data is to be fed into models for validation and future projections. Greater detail can be found in the Theme documents.


Oceans 2025 Theme 2: Marine Biogeochemical Cycles

Marine biogeochemical cycles are the key processes that control the cycling of climate-active gases within the surface ocean; the main transport mechanisms governing the supply of nutrients from deeper waters across the pycnocline; and the flux of material to deep water via the biological carbon pump. The broad aim of this Theme is to improve knowledge of major biogeochemical processes in the surface layer of the Atlantic Ocean and UK shelf seas in order to develop accurate models of these systems. This strategic research will result in predictions of how the ocean will respond to, and either ameliorate or worsen, climate change and ocean acidification.

Theme 2 comprises three Research Units and ten Work Packages. Theme 2 addresses the following pivotal biogeochemical pathways and processes:

  • The oceans and shelf seas as a source and sink of climate-active gases
  • The importance of the carbon and nitrogen cycles in the regulation of microbial communities and hence export and biogenic gas cycling
  • The biological pump and export of carbon into the ocean's interior
  • Processes that introduce nutrients into the euphotic zone
  • The direct impact of a high CO2 world (acidification) on mixed-layer biogeochemical cycles and feedbacks to the atmosphere via sea/air gas fluxes and the biological pump
  • The indirect impact of a high CO2 world (increased stratification and storminess) on the supply of nutrients to the surface layer of the ocean and hence on the biological carbon pump and air-sea gas fluxes
  • Cellular processes that mediate calcification in coccolithophores and how these are impacted by environmental change with a focus on elevated CO2 and ocean acidification
  • Inter- and intra-specific genetic diversity and inter-specific physiological plasticity in coccolithophores and the consequences of rapid environmental change

The official Oceans 2025 documentation for this Theme can be found using the following link: Oceans 2025 Theme 2


Oceans 2025 Theme 2, Work Package 2.5: Physical Processes and the Supply of Nutrients to the Euphotic Zone

The emphasis behind this Work Package is to gain a better understanding of the ocean's biological carbon pump (OBP), an important process in the global carbon cycle. Small changes in its magnitude resulting from climate change could have significant effects, both on the ocean's ability to sequester CO2 and on the natural flux of marine carbon. This work package is concerned with the effect of physical processes and circulation on nutrient supply to the euphotic zone. Many physical pathways influence nutrient supply, such as winter overturning, Ekman pumping, small-scale turbulent mixing and mesoscale ageostrophic circulations, (of which, eddy pumping is but one example). Increased stratification will change patterns of winter overturning and dampen small-scale mixing. Shifts in wind patterns will perturb Ekman pumping. Changes in gradients of ocean heating and wind-forcing will alter the distribution of potential energy released through baroclinic instability of eddies and fronts. The combined effect of change on total nutrient supply will therefore be complex. Such physically-mediated changes, coupled to changes in aeolian dust deposition, may profoundly alter upper ocean plankton communities, biogeochemical cycling and carbon export.

This Work Package will be primarily coordinated by the National Oceanography Centre, Southampton (NOC). Specific objectives are:

  • To determine the relative importance of mechanisms affecting nutrient supply to the photic zone by quantifying them in the three major biomes of the North Atlantic
  • To establish how representative process studies are for the basin scale and thus define operators to scale up the individual process study results
  • To determine the sensitivity to future climate change of the mechanisms sustaining total nutrient supply to the photic zone over the three major biomes of the North Atlantic

Aspects of this work will link to Oceans 2025 Theme 9 and 10, and Theme 2 WP 2.6.

More detailed information on this Work Package is available from pages 13-15 of the official Oceans 2025 Theme 2 document: Oceans 2025 Theme 2

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


Data Activity or Cruise Information

Cruise

Cruise Name D321 (D321A)
Departure Date 2007-07-24
Arrival Date 2007-08-23
Principal Scientist(s)John T Allen (National Oceanography Centre, Southampton)
Ship RRS Discovery

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