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Metadata Report for BODC Series Reference Number 1717489


Metadata Summary

Data Description

Data Category Currents -subsurface Eulerian
Instrument Type
NameCategories
Nortek Aquadopp 6000 3D Doppler current meter  current meters; water temperature sensor
Instrument Mounting subsurface mooring
Originating Country United Kingdom
Originator Mr Povl Abrahamsen
Originating Organization British Antarctic Survey
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) -
 

Data Identifiers

Originator's Identifier MOORING_ISTAR8_AQD_9391
BODC Series Reference 1717489
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2012-02-23 18:39
End Time (yyyy-mm-dd hh:mm) 2014-02-12 17:08
Nominal Cycle Interval 600.0 seconds
 

Spatial Co-ordinates

Latitude 74.86330 S ( 74° 51.8' S )
Longitude 102.10417 W ( 102° 6.3' W )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor or Sampling Depth 646.25 m
Maximum Sensor or Sampling Depth 646.25 m
Minimum Sensor or Sampling Height 307.75 m
Maximum Sensor or Sampling Height 307.75 m
Sea Floor Depth 954.0 m
Sea Floor Depth Source CRREP
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)
ACYCAA011DimensionlessSequence number
BTVOLTCM1VoltsVoltage of battery output by in-situ current meter
HEADCM011DegreesOrientation (horizontal relative to true north) of measurement device {heading}
ISCMBMA11DimensionlessSignal return amplitude from the water body by in-situ current meter beam 1
ISCMBMA21DimensionlessSignal return amplitude from the water body by in-situ current meter beam 2
ISCMBMA31DimensionlessSignal return amplitude from the water body by in-situ current meter beam 3
LCDAZZ011Degrees TrueDirection (towards) of water current in the water body
LCEWZZ011Centimetres per secondEastward velocity of water current in the water body
LCNSZZ011Centimetres per secondNorthward velocity of water current in the water body
LCSAZZ011Centimetres per secondSpeed of water current (Eulerian measurement) in the water body
LRZAZZZZ1Centimetres per secondUpward velocity of water current in the water body
PREXPR011DecibarsPressure (measured variable) exerted by the water body by semi-fixed in-situ pressure sensor and corrected to read zero at sea level
PTCHFG011DegreesOrientation (pitch) of measurement platform by triaxial fluxgate compass
ROLLFG011DegreesOrientation (roll angle) of measurement platform by triaxial fluxgate compass
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

No Problem Report Found in the Database

Quality report - iSTAR Moorings

It is clear from data from pressure sensors (and other sensors measuring the orientation of instruments on the mooring) that the iSTAR moorings were occasionally displaced in the water column. Given the location of the mooring it is likely that this disruption was caused by ice bergs knocking in to the mooring array. This was particularly noticeable in the data from moorings iSTAR6 (where the array became ~ 60m deeper on 05 January 2013), iSTAR9 (where the array became ~ 10 m deeper between 14 and 17 November 2013) and PIG_S (where the array became ~ 50 m deeper on the 20 July 2014 and then ~50 m deeper again on 30 July 2015).


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

Nortek Aquadopp Open Water Current Meter

This instrument provides 3D acoustic doppler current measurements along with standard measurements of temperature, pressure, tilt and direction. It can be used in real time measurement situations or can log to an internal recorder powered by internal batteries. It can also be configured to measure surface wave height, period and direction concurrently. It has the unique feature of being run in 'diagnostic' mode when set to collect data at 1 Hz frequency in user specified intervals. This allows studies of mooring motion and the performance of other current meters to be conducted. It can be set in various configurations with titanium housings for deployment at greater depths.

Standard Measured Parameters

  • 3D current velocity (East/North/Up, X/Y/Z or Beam 1/2/3)
  • Acoustic signal strength (Beam 1/2/3)
  • Compass
  • Tilt
  • Temperature
  • Pressure
  • Battery voltage
  • Status code
  • Error code

Surface wave monitoring

The standard Aquadopp is suitable for measuring surface wave height, period, and direction, which are calculated using the PUV method whereby spectra are estimated based on a combination of the pressure signal recorded by the instrument (P) and two horizontal components of the wave orbital velocity (U and V). More specifically, the pressure signal is used to provide an estimate of the wave frequency spectrum. The energy in this spectrum is then used to estimate wave height and period. The measurements of the wave orbital velocities are used to provide an estimate of the wave direction. Since these estimates are based on the distribution of wave energy and are not direct measurements of the free surface, they should be considered inferred estimates.

Both the dynamic pressure and the orbital velocities are driven by surface waves. The signals that are associated with these properties are complicated by the fact that they attenuate (that is the signals are weaker) with depth. The exact behaviour of the attenuation is determined by the water depth and the wavelength being observed. The greater the water depth the greater the attenuation; likewise, the shorter the wavelength (or higher the frequency of the wave) the greater the attenuation for a given water depth. This means that the estimation of wave parameters is limited by both water depth and wave frequency.

Specifications

Water Velocity Measurement
Range ± 5 m/s (standard 300 m version)
± 3 m/s (3000 m and 6000 m versions - higher ranges available on request)
Accuracy 1% of measured value ± 0.5 cm/s
Max. sampling rate 1 Hz, 4 Hz also available on request (standard version)
Internal sampling rate 23 Hz
Measurement Area
Measurement cell size 0.75 m
Measurement cell position 0.35 - 5.0 m
Default position 0.35 - 1.8 m
Doppler uncertainty (noise)
Typical 0.5 - 1.0 cm/s
At 1 Hz sampling rate 1.5 cm/s
Echo Intensity
Acoustic frequency 2 MHz
Resolution 0.45 dB
Dynamic range 90 dB
Sensors
Temperature Thermistor embedded in head
Range -4°C to 40°C
Accuracy/resolution 0.1°C / 0.01°C
Time response 10 min
Compass Magnetometer
Accuracy/Resolution 2° / 0.1° for tilt < 20°
Tilt Liquid level
Maximum tilt 30°
Up or down Automatic detect
Pressure Piezoresistive
Range 0 - 300 m (standard), 0 - 3000 m or 0 - 6000 m
Accuracy/resolution 0.5%
Analogue Inputs
No. of channels 2
Voltage supply 12 V
Voltage input 16 bit A/D
Materials
Standard version Delrin with titanium screws
3000 m version Delrin with titanium screws
6000 m version Titanium with Delrin transducer head
Environmental
Operating temperature -4°C to 40°C
Dimensions
Cylinder 568 mm x 75 mm (standard)
619 mm x 84 mm (3000 m version)
625 mm x 84 mm (6000 m version)
Weight in air 3.5 kg (standard)
3.6 kg (3000 m version)
7.6 kg (6000 m version)
Weight in water Neutral (standard)
1.2 kg (3000 m version)
4.8 kg (6000 m version)

Further details can be found in the manufacturer's specification sheets for the Aquadopp, Aquadopp 3000 and Aquadopp 6000.

BODC Processing - iSTAR Moored Nortek Aquadopps

Data were received by BODC in Matlab files, with one file containing all data from an iSTAR mooring array. The data were reformatted to QXF (a NetCDF file format) by in house software. A separate QXF file was created for data from each instrument. Metadata were also extracted from the originator's file and used to populate the BODC database.

The following tables shows how the variables within the files were mapped to appropriate BODC parameter codes:

Originator's parameter name Originator's units Description BODC Parameter Code BODC Units Comments
temp Degrees Celsius Temperature of the water body TEMPPR01 Degrees Celsius  
press dbar Pressure (measured variable) exerted by the water body by semi-fixed in-situ pressure sensor and corrected to read zero at sea level PREXPR01 dbar Depth data were also supplied by the originator but have not been ingested at BODC
speed cm/ s Current speed (Eulerian) in the water body LCSAZZ01 cm/ s  
dir Degrees Current direction in the water body LCDAZZ01 Degrees  
u cm/s Eastward current velocity in the water body LCEWZZ01 cm/s  
v cm/s Northward current velocity in the water body LCNSZZ01 cm/s  
w cm/s Upward current velocity in the water body LRZAZZZZ cm/s  
pitch Degrees Orientation (pitch) of measurement platform by triaxial fluxgate compass PTCHFG01 Degrees  
roll Degrees Orientation (roll angle) of measurement platform by triaxial fluxgate compass ROLLFG01 Degrees  
heading Degrees Orientation (horizontal relative to true north) of measurement platform {heading} by compass HEADCM01 Degrees  
amp1 Raw count Signal return amplitude from the water body by in-situ current meter beam 1 ISCMBMA1 dimensionless  
amp2 Raw count Signal return amplitude from the water body by in-situ current meter beam 2 ISCMBMA2 dimensionless  
amp3 Raw count Signal return amplitude from the water body by in-situ current meter beam 3 ISCMBMA3 dimensionless  
battery Volts Voltage (battery output) by in-situ current meter BTVOLTCM Volts  

Following transfer to QXF, the data were quality controlled using BODC's in-house visualisation software.

Originator's processing - iSTAR Moored Nortek Aquadopps

Data processing

The originator calibrated data from the moorings with data from CTD casts taken at deployment and recovery. Where appropriate offsets were applied (these are documented in the table below.

The magnetic variation calculated from the International Geomagnetic Reference Field (IGRF) at each mooring position on 01 January 2013 was recorded. The following variables had magnetic variation corrections applied by the originator:

  • current direction
  • northward component of current
  • eastward component of current

Magnetic variation corrections weren't applied to heading

Mooring Serial number Temperature offset applied (degrees Celsius) Pressure offset applied (dbar) Magnetic variation recorded
istar1 aqd_9392 0.0380 -5.2000 50.2416
istar4 aqd_9396 0.1170 -4.2000 50.9101
istar5 aqd_9368 0.0760 -5.8000 50.7405
istar5 aqd_9375 0.0570 -14.2000 50.7405
istar5 aqd_9386 0.1090 -4.4000 50.7405
istar6 aqd_9382 0.0260 -5.9000 49.5150
istar8 aqd_9391 0.0170 -5.7000 48.0830
istar9 aqd_9398 0.0380 -3.5000 48.3715
trough_w aqd_9368 0.0760 -5.8000 50.1867
trough_w aqd_9386 0.1090 -4.4000 50.1867
trough_e aqd_9375 0.0570 -14.2000 43.9542
trough_e aqd_9396 0.1170 -4.2000 43.9542
pig_n aqd_9391 0.0170 -5.7000 47.9776
pig_s aqd_9398 0.0380 -3.5000 48.2791

Project Information


No Project Information held for the Series

Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2012-02-23
End Date (yyyy-mm-dd) 2014-02-12
Organization Undertaking ActivityBritish Antarctic Survey
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifieriSTAR8
Platform Categorysubsurface mooring

iSTAR8 Mooring

iSTAR8 is a mooring array deployed for the iSTAR programme. The mooring was deployed from RV Araon in February 2012 and recovered from RRS James Clark Ross cruise JR20140126 in February 2014.

Deployment date (UTC) 2012-02-23 18:26
Recovery date (UTC) 2014-02-12 17:12
Latitude (+ve North) -74.8633
Longitude (+ve East) -102.1042
Nominal water depth (m) 954

Instrument setup

Instrument Serial number Nominal depth of instrument (m) Comments
Aquatec Aquatec Aqualogger 520PT Temperature and Pressure recorder 1306 471  
Aquatec Aquatec Aqualogger 520T Temperature recorder 1198 571  
Nortek Aquadopp 9391 671  
SeaBird SBE-37 Microcat 8534 672  
Aquatec Aquatec Aqualogger 520T Temperature recorder 1199 763  
Aquatec Aquatec Aqualogger 520T Temperature recorder 1200 863  
300 kHz RDI ADCP 15384 911  
SeaBird SBE-37 Microcat 8353 914  
Aquatec Aquatec Aqualogger 520T Temperature recorder 1201 938  

Related Data Activity activities are detailed in Appendix 1


Fixed Station Information

Fixed Station Information

Station NameiSTAR8 (mid-shelf)
CategoryCoastal location
Latitude74° 51.80' S
Longitude102° 6.25' W
Water depth below MSL954.0 m

iSTAR8 (PIG_N)

Fixed station Area Latitude, degrees (positive North) Longitude, degrees (positive East)
North-West corner -74.8633 -102.1042
South-East corner -74.8672 -102.0799

Water depth = 954 m

Sampling history

Activity Latitude Longitude Deployment date Recovery date Instruments Deployment ship/ cruise Recovery ship/ cruise Comments
iSTAR8 Mooring -74.8633 -102.1042 2012-02-23 2014-02-12 one Aquatec Aqualogger (temperature and pressure)
four Aquatec Aqualoggers (temperature only)
two SeaBird SBE-37 Microcats
one Nortec Aqaudopp
one 300 kHz RDI ADCP
RV Araon RRS James Clark Ross JR20140126  
CTD Cast 59 -74.8647 -102.0837 2014-02-18 N/A SeaBird SBE 911plus CTD
C-Star transmissometer
Aquatracka Fluorometer
SeaBird SBE-43 Oxygen sensor
PAR sensor
Altimeter PA200
RRS James Clark Ross JR20140126 N/A  
CTD bottle samples -74.8647 -102.0837 2014-02-18 N/A Salinity RRS James Clark Ross JR20140126 N/A  
PIG_N mooring -74.8672 -102.0799 2014-02-18 2016-02-02 one Aquatec Aqualogger (temperature and pressure)
six Aquatec Aqualoggers (temperature only)
two SeaBird SBE-37 Microcats
one Nortec Aqaudopp
one 300 kHz RDI ADCP
RRS James Clark Ross JR20140126 RV Araon ANA06B  .

Related Fixed Station activities are detailed in Appendix 2


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

Appendix 1: iSTAR8

Related series for this Data Activity are presented in the table below. Further information can be found by following the appropriate links.

If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.

Series IdentifierData CategoryStart date/timeStart positionCruise
1748600Currents -subsurface Eulerian2012-02-22 17:00:0074.8633 S, 102.10417 WNot applicable
1717428Hydrography time series at depth2012-02-23 18:39:5374.8633 S, 102.10417 WNot applicable
1717011Hydrography time series at depth2012-02-23 18:40:0174.8633 S, 102.10417 WNot applicable
1717023Hydrography time series at depth2012-02-23 18:40:0174.8633 S, 102.10417 WNot applicable
1717324Hydrography time series at depth2012-02-23 18:44:5374.8633 S, 102.10417 WNot applicable
1717336Hydrography time series at depth2012-02-23 18:44:5774.8633 S, 102.10417 WNot applicable
1717312Hydrography time series at depth2012-02-23 18:45:0074.8633 S, 102.10417 WNot applicable
1717300Hydrography time series at depth2012-02-23 18:45:0474.8633 S, 102.10417 WNot applicable
1748612Currents -subsurface Eulerian2013-01-01 00:08:1874.8633 S, 102.10417 WNot applicable

Appendix 2: iSTAR8 (mid-shelf)

Related series for this Fixed Station are presented in the table below. Further information can be found by following the appropriate links.

If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.

Series IdentifierData CategoryStart date/timeStart positionCruise
1748600Currents -subsurface Eulerian2012-02-22 17:00:0074.8633 S, 102.10417 WNot applicable
1717428Hydrography time series at depth2012-02-23 18:39:5374.8633 S, 102.10417 WNot applicable
1717011Hydrography time series at depth2012-02-23 18:40:0174.8633 S, 102.10417 WNot applicable
1717023Hydrography time series at depth2012-02-23 18:40:0174.8633 S, 102.10417 WNot applicable
1717324Hydrography time series at depth2012-02-23 18:44:5374.8633 S, 102.10417 WNot applicable
1717336Hydrography time series at depth2012-02-23 18:44:5774.8633 S, 102.10417 WNot applicable
1717312Hydrography time series at depth2012-02-23 18:45:0074.8633 S, 102.10417 WNot applicable
1717300Hydrography time series at depth2012-02-23 18:45:0474.8633 S, 102.10417 WNot applicable
1748612Currents -subsurface Eulerian2013-01-01 00:08:1874.8633 S, 102.10417 WNot applicable
1748728Currents -subsurface Eulerian2014-02-18 14:20:0074.8672 S, 102.07992 WRRS James Clark Ross JR20140126 (JR294, JR295)
1748808Hydrography time series at depth2014-02-18 14:20:0074.8672 S, 102.07992 WRRS James Clark Ross JR20140126 (JR294, JR295)
1748821Hydrography time series at depth2014-02-18 14:20:0074.8672 S, 102.07992 WRRS James Clark Ross JR20140126 (JR294, JR295)
1748833Hydrography time series at depth2014-02-18 14:20:0074.8672 S, 102.07992 WRRS James Clark Ross JR20140126 (JR294, JR295)
1748845Hydrography time series at depth2014-02-18 14:20:0074.8672 S, 102.07992 WRRS James Clark Ross JR20140126 (JR294, JR295)
1748857Hydrography time series at depth2014-02-18 14:20:0074.8672 S, 102.07992 WRRS James Clark Ross JR20140126 (JR294, JR295)
1748869Hydrography time series at depth2014-02-18 14:20:0074.8672 S, 102.07992 WRRS James Clark Ross JR20140126 (JR294, JR295)
1748949Hydrography time series at depth2014-02-18 14:20:0074.8672 S, 102.07992 WRRS James Clark Ross JR20140126 (JR294, JR295)
1763922Hydrography time series at depth2014-02-18 14:20:0174.8672 S, 102.07992 WRRS James Clark Ross JR20140126 (JR294, JR295)
1763934Hydrography time series at depth2014-02-18 14:20:0174.8672 S, 102.07992 WRRS James Clark Ross JR20140126 (JR294, JR295)
1748624Currents -subsurface Eulerian2014-02-18 14:30:0074.8672 S, 102.07992 WRRS James Clark Ross JR20140126 (JR294, JR295)
1748636Currents -subsurface Eulerian2015-01-01 00:08:1274.8672 S, 102.07992 WRRS James Clark Ross JR20140126 (JR294, JR295)
1748648Currents -subsurface Eulerian2016-01-01 00:17:4174.8672 S, 102.07992 WRRS James Clark Ross JR20140126 (JR294, JR295)