Metadata Report for BODC Series Reference Number 1039441


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 Marine Scotland Aberdeen Marine Laboratory
Processing Status banked
Project(s) -
 

Data Identifiers

Originator's Identifier 782/1
BODC Series Reference 1039441
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2010-01-08 11:00
End Time (yyyy-mm-dd hh:mm) 2010-05-18 17:00
Nominal Cycle Interval 1800.0 seconds
 

Spatial Co-ordinates

Latitude 60.31150 N ( 60° 18.7' N )
Longitude 0.69667 W ( 0° 41.8' W )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor Depth 44.0 m
Maximum Sensor Depth 44.0 m
Minimum Sensor Height 52.0 m
Maximum Sensor Height 52.0 m
Sea Floor Depth 96.0 m
Sensor Distribution Fixed common depth - All sensors are grouped effectively at the same depth which is effectively fixed for the duration of the series
Sensor 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 CODE Rank Units Short Title Title
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)
LCDAEL01 1 Degrees True CurrDir Current direction (Eulerian) in the water body by in-situ current meter and correction to true North
LCSAEL01 1 Centimetres per second CurrSpd_CM Current speed (Eulerian) in the water body by in-situ current meter
TEMPPR01 1 Degrees Celsius Temp Temperature 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

No Problem Report Found in the Database

Data quality report

On several occasions the current speed fell below the detection threshold of the current meter, resulting in the data flatlining at 0 ms-1.


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 reformatted to QXF (a netCDF format) using the BODC transfer function 325. 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), LCSAEL01 (speed) °, cm/s 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
Temperature °C TEMPPR01 °C  

Following transfer to QXF, the data were screened using BODC's in-house visualisation software, EDSERPLO. Any data considered as suspect were flagged accordingly. Flags from the originator marking suspect data 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) 2010-01-08
End Date (yyyy-mm-dd) 2010-05-18
Organization Undertaking ActivityMarine Scotland Aberdeen Marine Laboratory
Country of OrganizationUnited Kingdom
Originator's Data Activity Identifier782
Platform Categorysubsurface mooring

FRS current meter mooring (782) from East Shetland 1

A current meter mooring was deployed by Marine Scotland, Aberdeen Marine Laboratory at site East Shetland 1 (60° 18.69'N 00° 41.80'W) on 08/01/2010 during the FRV Scotia cruise 0110S. The mooring was recovered on 18/05/2010 by the FRV Scotia cruise 0610S. The station had a nominal water depth of 96m.

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 7821 909 08/01/2010 18/05/2010 44 2 -
Aanderaa RCM7 7822 12413 08/01/2010 18/05/2010 87 2 Current record cut short at 14:30 6/2/10 due to fouling. Salinity degradation due to fouling.

Other Series linked to this Data Activity - 1043661

Cruise

Cruise Name 0110S
Departure Date 2010-01-06
Arrival Date 2010-01-21
Principal Scientist(s)Marie Russell (Marine Scotland 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