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Metadata Report for BODC Series Reference Number 1039244


Metadata Summary

Data Description

Data Category Currents -subsurface Eulerian
Instrument Type
NameCategories
Aanderaa RCM 7/8 Recording Current Meter  current meters
Instrument Mounting subsurface mooring
Originating Country United Kingdom
Originator Ms Sarah Hughes
Originating Organization Fisheries Research Services Aberdeen Marine Laboratory (now Marine Scotland Aberdeen Marine Laboratory)
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) -
 

Data Identifiers

Originator's Identifier 764/2
BODC Series Reference 1039244
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2008-09-27 16:00
End Time (yyyy-mm-dd hh:mm) 2009-05-08 09:30
Nominal Cycle Interval 1800.0 seconds
 

Spatial Co-ordinates

Latitude 59.47150 N ( 59° 28.3' N )
Longitude 2.03050 W ( 2° 1.8' W )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor or Sampling Depth 89.0 m
Maximum Sensor or Sampling Depth 89.0 m
Minimum Sensor or Sampling Height 13.0 m
Maximum Sensor or Sampling Height 13.0 m
Sea Floor Depth 102.0 m
Sea Floor Depth Source -
Sensor or Sampling Distribution Fixed common depth - All sensors are grouped effectively at the same depth which is effectively fixed for the duration of the series
Sensor or Sampling Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
 

Parameters

BODC CODERankUnitsTitle
AADYAA011DaysDate (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ011DaysTime (time between 00:00 UT and timestamp)
LCDAEL011Degrees TrueDirection (towards) of water current (Eulerian measurement) in the water body by in-situ current meter and correction to true North
LCSAEL011Centimetres per secondSpeed of water current (Eulerian measurement) in the water body by in-situ current meter
PSALPR011DimensionlessPractical salinity of the water body by conductivity cell and computation using UNESCO 1983 algorithm
TEMPPR011Degrees CelsiusTemperature of the water body

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

This mooring was trawled at 10:30 on 19/02/09. Current data from this point was deleted by the originator. The quality of the salinity and temperature data seem to degrade past this point and should therefore be treated with caution.


Data Access Policy

Public domain data

These data have no specific confidentiality restrictions for users. However, users must acknowledge data sources as it is not ethical to publish data without proper attribution. Any publication or other output resulting from usage of the data should include an acknowledgment.

The recommended acknowledgment is

"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."


Narrative Documents

Aanderaa Recording Current Meter Model 7/8

Manufacturer's specifications: recording unit height 49.5cm (RCM8 52.0cm), diameter 12.8cm, vane size 48.5x50.0cm. Meter is designed for depths down to 2000m (RCM8 6000m). It incorporates a spindle which is shackled to the mooring line. The meter is attached to the spindle through a gimbal mounting which permits a maximum 27° deviation of the spindle from the vertical, the meter still remaining horizontal.

Meter comprises :

  1. Paddle wheel rotor magnetically coupled to an electronic counter

  2. Vane, which aligns instrument with current flow, has a balance weight ensuring static balance and tail fins to ensure dynamic balance in flows up to 250cm/s.

  3. Magnetic compass (needle is clamped to potentiometer ring) - direction recorded with 0.35° resolution, 5° accuracy for speeds 5 to 100cm/s, 7.5° accuracy for remaining speeds within 2.5 to 200cm/s range.

  4. Quartz clock, accuracy better than 2 sec/day within temperature range 0 to 20°C.

  5. Thermistor (temperature sensor), standard range -2.46 to 21.48°C (max on high range 36.04°C), accuracy 0.05°C, resolution 0.1 per cent of range, 63 per cent response time 12sec.

  6. Inductive cell conductivity sensor (optional), range 0 to 70mmho/cm standard resolution 0.1 per cent of range.

  7. Silicon piezoresistive bridge, standard range 0 to 3000 psi (RCM8 to 9000 psi), resolution 0.1% of range.

  8. Self balancing potentiometer which converts the output from each sensor into a 10 bit binary number for storage on magnetic tape.

  9. Associated electronics.

A built-in clock triggers the instrument at preset intervals and up to six channels are sampled in sequence. Channel 1 is a fixed reference reading for control purposes and data identification. Channels 2, 3 and 4 represent measurement of temperature, conductivity and pressure. Channels 5 and 6 represent the VECTOR AVERAGED current speed and direction since the previous triggering of the instrument. The number of rotor revolutions and the direction is sampled every 12 seconds and broken into North and East components. Successive components are added and recorded as speed and direction. For recording intervals longer than 10 minutes, speed and direction are sampled 1/50th of recording interval.

It has become common practice in some laboratories to deploy these meters as temperature and conductivity loggers without current measuring capabilities.

The following link will provide the manufacturer specifications:

Manufacturer specifications

BODC Processing

Data were received in ASCII format files. The series were transferred to BODC's in-house format. The following table shows how the variables within the file were mapped to the appropriate BODC parameter codes.

Original parameter name Original Units BODC Parameter Code BODC Units Comments
Time DD/MM/YYYY HH:MI (GMT) AADYAA01, AAFDZZ01 day number, day fraction Conversion by transfer
Eastward and northward current velocity (u + v) cm/s LCDAEL01 (direction) ° Converted by transfer to current direction (Eulerian) in the water column by in-situ current meter and correction to true North, and current speed (Eulerian) in the water column by in-situ current meter
LCSAEL01 (speed) cm/s
Temperature °C TEMPPR01 °C Where present
Salinity p.p.t. PSALPR01 Dimensionless Where present

Following reformatting, the data were visually screened. Any data considered suspect were flagged accordingly. The originator's quality control flags were retained during transfer.

Originator's Data Processing

Marine Scotland applied the standard manufacturers' calibrations to all current, temperature and salinity data and produced ASCII files for submission to BODC. Data files (.hmo) were named according to the mooring code and the instrument number. Each current meter file contained eastward and northward velocities and temperature. In cases where the temperature data ran for longer than the current data, the temperature records were saved as separate files appended 't'. Salinity data for each instrument were contained in files appended 's'. Header metadata were collated in additional files (.frm). Speed/Direction distributions (.csd) and harmonic analyses files (.lpr) for the current meter data were also generated.


Project Information


No Project Information held for the Series

Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2008-09-27
End Date (yyyy-mm-dd) 2009-05-17
Organization Undertaking ActivityFisheries Research Services Aberdeen Marine Laboratory (now Marine Scotland Aberdeen Marine Laboratory)
Country of OrganizationUnited Kingdom
Originator's Data Activity Identifier764
Platform Categorysubsurface mooring

FRS current meter mooring (764) from Fair Isle Channel South

A mounted Aanderaa Recording Current Meter (RCM7) was deployed by Marine Scotland, Aberdeen Marine Laboratory in Fair Isle Channel South (59° 28.29'N, 02° 01.83'W) on 27/09/2008 during the FRV Scotia cruise 1208S_1. The mooring was recovered on 17/05/2009 by the FRV Scotia cruise 0709S. The station had a nominal water depth of 102m and the instrument was deployed at a depth of 89m.

The mooring consisted of the following instruments

Instrument type Series Number Serial Number Deployment start Deployment end Instrument depth (m) No. Readings/Hour Comments
Aanderaa RCM7 7642 9946 27/09/2008 17/05/2009 89 2 This mooring was trawled on at 10:30 on 19/02/09. Current data from this point onwards have been deleted by the originator

Cruise

Cruise Name 1208S_1
Departure Date 2008-09-26
Arrival Date 2008-10-09
Principal Scientist(s)George Slesser (Fisheries Research Services Aberdeen Marine Laboratory)
Ship FRV Scotia

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