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Metadata Report for BODC Series Reference Number 649597


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 Prof Kelvin Richards
Originating Organization University of Southampton School of Ocean and Earth Science
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) Marine Productivity
 

Data Identifiers

Originator's Identifier ADP26202
BODC Series Reference 649597
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2002-04-19 07:59
End Time (yyyy-mm-dd hh:mm) 2002-04-20 10:28
Nominal Cycle Interval 30.0 seconds
 

Spatial Co-ordinates

Southernmost Latitude 50.68198 N ( 50° 40.9' N )
Northernmost Latitude 55.53219 N ( 55° 31.9' N )
Westernmost Longitude 6.44255 W ( 6° 26.6' W )
Easternmost Longitude 5.25269 W ( 5° 15.2' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth 18.0 m
Maximum Sensor or Sampling Depth 522.0 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)
ALATGP011DegreesLatitude north relative to WGS84 by unspecified GPS system
ALONGP011DegreesLongitude east relative to WGS84 by unspecified GPS system
ASAMAS012DecibelsSignal return amplitude from the water body by shipborne 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)
LRZAAS012Centimetres per secondUpward velocity of water current in the water body by shipborne acoustic doppler current profiler (ADCP)
PCGDAP012PercentAcceptable proportion of acoustic signal returns {percent good} 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

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

RRS Discovery 262 150kHz VMADCP

Deployment and originator's processing

Two RDI Vessel-Mounted Acoustic Doppler Current Profilers (VM-ADCPs) were operated on Discovery 262; the 150kHz VM-ADCP and the 75 kHz Phased Array instrument (Ocean Surveyor) that had been fitted immediately prior to FISHES (Discovery 253, May-June 2001). The 150 kHz ADCP is mounted 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. The 75 kHz ADCP is mounted in a second well in the hull, but 4.15 m forward and 2.5 m to starboard of the 150 kHz well. The following table describes the setup of the 150kHz ADCP.

Frequency dependent constant 4.17e5
Power into water (W) 183.15
Dimensionless noise factor 8.95
Bin length (m) 4
Blanking distance (m) 4

BODC processing

A total of 36 files were submitted to BODC. The data were supplied in P* binary format. The following variables were transferred to BODC QXF format (a BODC-defined subset of NetCDF and BODC's format for 2 dimensionsal datacycle storage) using transfer process tr363. The only variables not transferred were the non-calibrated backscatter and the time channel (the latter being automatically calculated by the transfer program).

BODC Code Description Units Originator's variable
ALATGP01 Latitude degrees lat
ALONGP01 Longitude degrees lon
AADYAA01 Date (time from 00:00 01/01/1760 to 00:00 UT on day) days time
AAFDZZ01 Time (time between 00:00 UT and timestamp) days time
DBINAA01 Bin depth metres bindepth
ASAMAS01 Signal return amplitude decibels ampl
LCEWAS01 Eastward current velocity (Eulerian) cm/s absve
LCNSAS01 Northward current velocity (Eulerian) cm/s absvn
LERRAS01 Current velocity error cm/s velerr
LRZAAS01 Upward current velocity cm/s velvert
PCGDAP01 Percentage good return signal % good

Screening and Data quality

The data have been visually screened for obvious problems using the BODC EDSERPLO software. No significant problems were detected apart for the Eastward and Northward current velocities for day file with ISHREF 649616 (originator's id: adp26204.abs) which mirror the ship's velocity. Examination of the originator's pstar file reveals that the platform velocities are always zero for this particular file resulting in the error for absolute current velocity. To avoid confusion, the absolute current velocities for this file have been deleted. Note that, for an unkown reason, the first 6 day files (ISHREFs 04400, 04500, 04600, 04700, 04800, 04900) only have 64 bins each, ranging from 18m to 522m, compared to 100 bins within 14m to 410m range for all the other files.


Project Information

Marine Productivity programme (MarProd)

The Marine Productivity programme (MarProd) was a Thematic Programme of the Natural Environment Research Council. It was funded for a period of five years starting in 2000. Its main goal was "to develop coupled modelling and observation systems for the pelagic ecosystem, with emphasis on physical factors affecting zooplankton dynamics" with the following specific objectives:

  • To identify the dominant spatial and temporal scales of physical parameters and zooplankton population dynamics, by observation, modelling and retrospective analysis

  • To parameterise the critical processes governing zooplankton dynamics by observations and experiments

  • To construct and validate spatially explicit models of zooplankton and their food and predators, capable of resolving short term changes in population structure

  • To provide data for model validation by developing and applying new interdisciplinary techniques to a wide spectrum of biological and physical parameters

  • To develop a database and information system for historic and new data and models.

The programme was composed of two phases: Phase 1 projects (2000-2002) focused on the use of historical datasets and existing biological models, complemented by laboratory experiments and remote-sensing analyses to gain a better understanding of the dynamics of zooplankton populations in shelf seas. The main, field-based Phase 2 of the programme (2001-2005) focused on the open ocean. The fieldwork phase took place between November 2001 and December 2002 and consisted of four surveys in the northern North Atlantic in early winter 2001 and 2002, and in spring and summer 2002.

MarProd was a major UK contribution to the international Global Ocean Ecosystem Dynamics project (GLOBEC).


Data Activity or Cruise Information

Cruise

Cruise Name D262
Departure Date 2002-04-18
Arrival Date 2002-05-26
Principal Scientist(s)Kelvin Richards (University of Southampton School of Ocean and Earth Science)
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
B nominal value
Q value below limit of quantification