Metadata Report for BODC Series Reference Number 1929929

Metadata Summary
Problem Reports
Data Access Policy
Narrative Documents
Project Information
Data Activity or Cruise Information
Fixed Station Information
BODC Quality Flags
SeaDataNet Quality Flags

Metadata Summary

Data Description

Data Category

Currents -subsurface Eulerian

Instrument Type

Name	Categories
Teledyne RDI 300kHz Workhorse Monitor direct-reading ADCP	current profilers

Instrument Mounting

lowered unmanned submersible

Originating Country

United Kingdom

Originator

Ms Jane Read

Originating Organization

National Oceanography Centre, Southampton

Processing Status

banked

Online delivery of data

Download available - Ocean Data View (ODV) format

Project(s)

Oceans 2025

Data Identifiers

Originator's Identifier	LADCP_035
BODC Series Reference	1929929

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm)	2010-05-19 14:05
End Time (yyyy-mm-dd hh:mm)	-
Nominal Cycle Interval	10.0 metres

Spatial Co-ordinates

Latitude	57.49750 N ( 57° 29.9' N )
Longitude	11.85090 W ( 11° 51.1' W )
Positional Uncertainty	0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth	10.0 m
Maximum Sensor or Sampling Depth	1770.0 m
Minimum Sensor or Sampling Height	10.81 m
Maximum Sensor or Sampling Height	1770.82 m
Sea Floor Depth	1780.82 m
Sea Floor Depth Source	GEBCO1901
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	Chart reference - Depth extracted from available chart

Parameters

BODC CODE	Rank	Units	Title
ACYCAA01	1	Dimensionless	Sequence number
ADEPZZ01	1	Metres	Depth (spatial coordinate) relative to water surface in the water body
ERRVLDCP	1	Centimetres per second	Error velocity of water current in the water body by lowered acoustic doppler current profiler (ADCP)
LCEWLW01	1	Centimetres per second	Eastward velocity of water current (Eulerian measurement) in the water body by lowered acoustic doppler current profiler (ADCP)
LCNSLW01	1	Centimetres per second	Northward velocity of water current (Eulerian measurement) in the water body by lowered 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

Teledyne RDI's Workhorse Monitor ADCP

The Workhorse Monitor acoustic doppler current profler (Teledyne RD Instruments) is a long-range and long-term self contained ADCP. It has a patented four beam signal (300, 600 or 1200 kHz) and a standard depth rating of 200m or 600m. It operates effectively between temperatures of -5°C and 45°C and has a velocity accuracy of ±1% ±5mm/s.

BODC Data Processing

The LADCP data were supplied as individual files in .lad format. All data provided were from two downward looking Teledyne RDI Workhorse 300 kHz ADCP's, which were in operation at the time. The following table shows how the variables within the ASCII files were mapped to appropriate BODC parameter codes:

Originator's Variable	Originator's Units	BODC Parameter Code	BODC Units	Comments
z	m	ADEPZZ01	m	-
u	m s^-1	LCEWLW01	cm s^-1	Units converted from m s^-1 to cm s^-1 by multiplying by 100.
v	m s^-1	LCNSLW01	cm s^-1	Units converted from m s^-1 to cm s^-1 by multiplying by 100.
ev	m s^-1	ERRVLDCP	cm s^-1	Units converted from m s^-1 to cm s^-1 by multiplying by 100.

All reformatted data were visualised using the in-house Edserplo software. Suspect and missing data were marked by adding an appropriate quality control flag.

Originator's Data Processing

Instrument description

Two Teledyne RDI Workhorse 300 kHz lowered acoustic Doppler current profilers (LADCP) (serial numbers 13329 and 10607) were mounted on two CTD frames, both were positioned in a downward looking orientation. Serial number 13329 was mounted on the stainless steel frame and was last serviced 21^st September 2009. Serial number 10607 was mounted on the titanium frame and was last serviced 26^th March 2008. Both instruments worked well throughout the cruise, without any evidence of problems.

Sampling strategy

CTD casts were taken during cruise D351, occupying 62 stations across the Ellett Line and Extended Ellett Line, from which 49 Lowered Acoustic Doppler Current Profiler (LADCP) profiles are available. Processing of LADCP data from stations 010, 025, 051, 052, 055, and 057 crashed, and of these, stations 051, 052, 055, and 057 were in shallow water where there were insufficient data for the processing to work. It is not clear why stations 010 and 025 failed to process as inspection of the LADCP data with the RDI software winADCP identified nothing wrong. It is unknown why data were not provided for station 043.

Data processing

Data were processed using MatLab Visbeck v10 software. The Visbeck software incorporates ship's position, CTD pressure and vessel mounted ADCP (VM-ADCP) currents to obtain the best solution for water column currents. However, VM-ADCP data were not ready during the cruise so the processing was run without. CTD data were merged with the 'abnv3511' (bestnav) file for position, then converted from PSTAR 2db files to MATLAB format. Time, position and pressure were separated into different .mat files for the Visbeck software.

Please refer to page 60 of the cruise report for more details about the processing methodology.

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.

Data Activity or Cruise Information

Cruise

Cruise Name	D351
Departure Date	2010-05-11
Arrival Date	2010-05-28
Principal Scientist(s)	Jane F Read (National Oceanography Centre, Southampton)
Ship	RRS Discovery

Complete Cruise Metadata Report is available here

Fixed Station Information

Station Name	Ellett Line/Extended Ellett Line Station G
Category	Offshore location
Latitude	57° 29.52' N
Longitude	11° 51.00' W
Water depth below MSL	1812.0 m

Ellett Line/Extended Ellett Line: Station G

Station G is one of the fixed CTD stations, which together form The Extended Ellett Line. The line lies between Iceland and the Sound of Mull (Scotland) crossing the Iceland Basin and Rockall Trough via the outcrop of Rockall. As part of this initiative, CTD dips, together with associated discrete sampling of the water column, have typically been carried out annually at this station since September 1996.

Prior to September 1996, Station G was part of a shorter repeated survey section, consisting of 35 fixed stations, known as The Ellett Line (originally termed the Anton Dohrn Seamount Section). This line incorporated those stations across the Rockall Trough and Scottish shelf between Rockall and the Sound of Mull and was visited at regular intervals (usually at least once a year) between 1975 and January 1996.

Related Fixed Station activities are detailed in Appendix 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

SeaDataNet Quality Control Flags