Metadata Report for BODC Series Reference Number 1193136


Metadata Summary

Data Description

Data Category Currents -subsurface Eulerian
Instrument Type
NameCategories
Teledyne RDI Ocean Surveyor 150kHz vessel-mounted ADCP  current profilers
Instrument Mounting research vessel
Originating Country United Kingdom
Originator Dr Brian King
Originating Organization National Oceanography Centre, Southampton
Processing Status banked
Project(s) Oceans 2025
Oceans 2025 Theme 10
Oceans 2025 Theme 10 SO3: MOC
 

Data Identifiers

Originator's Identifier OS150_DI346NNX_01
BODC Series Reference 1193136
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2010-01-06 07:37
End Time (yyyy-mm-dd hh:mm) 2010-02-18 10:34
Nominal Cycle Interval -
 

Spatial Co-ordinates

Start Latitude 26.63710 N ( 26° 38.2' N )
End Latitude 37.93370 N ( 37° 56.0' N )
Start Longitude 79.07540 W ( 79° 4.5' W )
End Longitude 9.34310 W ( 9° 20.6' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth 19.23 m
Maximum Sensor Depth 531.29 m
Minimum Sensor Height -
Maximum Sensor Height -
Sea Floor Depth -
Sensor Distribution Sensor fixed, measurements made at fixed depths - 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 Depth Datum Approximate - Depth is only approximate
Sea Floor Depth Datum -
 

Parameters

BODC CODE Rank Units Short Title Title
BINNUMBR 0 Dimensionless BinNum Bin number
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
ALATGP01 1 Degrees Lat_GPS Latitude north (WGS84) by unspecified GPS system
ALONGP01 1 Degrees Lon_GPS Longitude east (WGS84) by unspecified GPS system
APEWZZ01 1 Centimetres per second PlatformVelE Eastward velocity (over ground) of measurement platform
APNSZZ01 1 Centimetres per second PlatformVelN Northward velocity (over ground) of measurement platform
DBINAA01 2 Metres BinDep Depth below sea surface (ADCP bin)
LCEWAS01 2 Centimetres per second CurrVelE_ADCP Eastward current velocity (Eulerian) in the water body by shipborne acoustic doppler current profiler (ADCP)
LCNSAS01 2 Centimetres per second CurrVelN_ADCP Northward current velocity (Eulerian) in the water body by shipborne 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

RD Instruments- Ocean Surveyor 150kHz Vessel mounted ADCP.

Long-Range Mode
Vertical Resolution Cell Size 3 Max. Range (m) 1 Precision (cm/s) 2
4m 325 - 350 30
8m 375 - 400 19
High-Precision Mode
Vertical Resolution Cell Size 3 Max.Range (m) 1 Precision (cm/s) 2
4m 200 - 250 12
8m 220 - 275 9

1 Ranges at 1 to 5 knots ship speed are typical and vary with situation.
2 Single-ping standard deviation.
3 User's choice of depth cell size is not limited to the typical values specified.

Profile Parameters

Bottom Track

Maximum altitude (precision <2cm/s): 600m

Echo Intensity Profile

Dynamic range: 80dB
Precision: ±1.5dB

Transducer & Hardware

Beam angle: 30°
Configuration: 4-beam phased array
Communications: RS-232 or RS-422 hex-ASCII or binary output at 1200 - 115,200 baud
Output power: 1000W

Standard Sensors

Temperature (mounted on transducer)

Environmental

Operating temperature: -5° to 40°C (-5° to 45°C)*
Storage temperature: -30° to 50°C (-30° to 60°C)*

*later instruments have greater range.

Web Page

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

D346 150kHz Shipboard ADCP data processing

Originator's processing

The following was taken from the D346 cruise report. For more detailed information please refer to King (2010).

The data from the 150kHz Ocean Surveyor vessel mounted ADCP were acquired using RD Instruments VmDas software package 1.42. A new sequence number and hence file was creating every time a file size reached 10Mb. Real time plots of the data were inspected throughout the cruise using WinADCP software to check the data stream and inform the bridge of ADCP measurements as required on station.

The instrument was run in narrowband single ping mode. Where depth permitted, for the first few days of the cruise, the instrument was run in bottom track mode to obtain the most accurate phase and amplitude calibrations. 65 bins were used at a size of 8m. A blanking distance of 6m was used in order to avoid ringing from the transmit pulse. Using VmDas the instrument was switched between bottom track and water track on day 009 when the sea floor was out of range of bottom tracking.

Measurements of x and y velocities are independent of the speed of sound for phased array ADCP instruments such as the 150kHz OS (King et al., 2010).

Final processing of the data was done using the CODAS (common Ocean Data Access System) suite of software provided by the University of Hawaii. This suite allows manual inspection and editing of bad profiles and provides the best estimates of the required rotation of the data, either from water profiling or bottom tracking.

The best calibration estimates are obtained when the velocity data is collected using the seabed as a reference. However, bottom track calibration estimates are only obtainable when water depth is within the ADCP profiling range. Bottom tracking was performed at the beginning of the cruise from Julian day 006-009 and again when the ship reached the continental shelf of Morocco, to check the rotations derived at the beginning of the cruise had not changed. The derived calibration was -1.58 and 1.0005 for rotation angle and amplitude, respectively. The data are checked after calibration to ensure that any vertical striping associated with on/off station differences had been removed. Gaudedit was then used to removed bad profiles or bad bins.

Data quality issues

Two potential issues arise from the presence of bubbles immediately below the transducer face. Bubbles can prevent penetration of the transmit pulse and lead to truncated or bad profiles. This was not widely observed on this cruise. The high amplitude return from bubbles can cause anomalous velocities in the direction of the ship steaming. It is commonly identified by a relatively low percentage good in the top few bins and a red surface stripe in the along-track bias parameter. There were relatively few incidences of bubble bias encountered significant enough to warrant editing of the data.

References

King, B. A., et al 'RRS James Cook Cruise 032, 07 Mar - 21 Apr 2009. Hydrographic sections across the Brazil Current and at 24°S in the Atlantic. Southampton, UK: National Oceanography Centre, Southampton, 173pp, National Oceanography Centre Cruise Report, No 48.'

King, B. A., et al RRS Discovery Cruise 346, 05 Jan - 19 Feb 2010. The 2010 transatlantic hydrography section at 24.5°N. Southampton, UK: National Oceanography Centre, Southampton, 177pp, National Oceanography Centre Cruise Report, No 16.

BODC processing

The data were converted from Mstar format into BODC internal format, a netCDF subset, to allow use of in-house visualisation tools. The table below shows the mapping of originator variables to BODC Parameter codes.

Originator's variable Units Description BODC Parameter Code Units Comments
lon Degrees Longitude ALONGP01 Degrees -
lat Degrees Latitude ALATGP01 Degrees -
depth (of bin) m Depth of ADCP bin DBINAA01 m -
uabs cm s -1 Absolute Eastward current velocity LCEWAS01 cm s -1 -
vabs cm s -1 Absolute Northward current velocity LCNSAS01 cm s -1 -
uship m s -1 Ship's Eastward velocity APEWGP01 cm s -1 Values converted by multiplication by 100.
vship m s -1 Ship's Northward velocity APNSGP01 cm s -1 Values converted by multiplication by 100.
speed cm s -1 Scalar current speed - - Variable not transferred. Superseded by vector values
shipspd cm s -1 Scalar ship speed - - Variable not transferred. Superseded by vector values

Reformatted data were visually checked using the in-house editor EDSERPLO. No data values were edited or deleted. Flagging was achieved by modification of the associated quality control flag to 'M' for suspect values and 'N' for nulls.

Once quality control screening was complete, the data were archived in the BODC National Oceanographic Database and the associated metadata were loaded into an ORACLE Relational Database Management System.


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:

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:

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:

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

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:

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 10

Oceans 2025 is a strategic marine science programme, bringing marine researchers together to increase people's knowledge of the marine environment so that they are better able to protect it for future generations.

Theme 10: Integration of Sustained Observations in the Marine Environment spans all marine domains from the sea-shore to the global ocean, providing data and knowledge on a wide range of ecosystem properties and processes (from ocean circulation to biodiversity) that are critical to understanding Earth system behaviour and identifying change. They have been developed not merely to provide long-term data sets, but to capture extreme or episodic events, and play a key role in the initialisation and validation of models. Many of these SOs will be integrated into the newly developing UK Marine Monitoring Strategy - evolving from the Defra reports Safeguarding our Seas (2002) and Charting Progress (2005), thus contributing to the underpinning knowledge for national marine stewardship. They will also contribute to the UK GOOS Strategic Plan (IACMST, 2006) and the Global Marine Assessment.

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


Oceans 2025 Theme 10, Sustained Observation Activity 3: Monitoring the Atlantic Meridional Overturning Circulation

The Meridional Overturning Circulation (MOC) is the key component of ocean circulation in the Atlantic responding to climate change. Under the NERC directed programme Rapid Climate Change (RAPID) two arrays of instruments have been positioned in the ocean to monitor the MOC, one at 26.5 °N to capture the southward flow at depth, and the Western Atlantic Variability Experiment (WAVE) array across the Canadian-US continental slope, closer to the presumed source variations. Sustained Observation Activity (SO) 3 will continue these measurements to observe the strength and structure of the MOC, working closely with Oceans 2025 Theme 1 and the RAPID-WATCH directed programme.

There are two elements to this SO activity. SO 3.1. relates to the E-W mooring array in the mid-North Atlantic at 26.5 °N while SO 3.2. is concerned with the Western Atlantic array between Cape Cod and the Grand Banks.

Aims and Purpose of SO 3.1.

Aims and Purpose of SO 3.2.

More detailed information on this Work Package is available at pages 11 - 14 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 D346
Departure Date 2010-01-05
Arrival Date 2010-02-19
Principal Scientist(s)Brian A King (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