Metadata Report for BODC Series Reference Number 1374337

Metadata Summary
Problem Reports
Data Access Policy
Narrative Documents
Project Information
Data Activity or Cruise Information
Fixed Station Information
BODC Quality Flags
SeaDataNet Quality Flags

Metadata Summary

Data Description

Data Category

Currents -subsurface Eulerian

Instrument Type

Name	Categories
Aanderaa doppler current sensor 4100	current meters

Instrument Mounting

subsurface mooring

Originating Country

United Kingdom

Originator

Ms Sarah Hughes

Originating Organization

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	836/1
BODC Series Reference	1374337

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm)	2013-04-19 12:41
End Time (yyyy-mm-dd hh:mm)	2013-05-08 07:31
Nominal Cycle Interval	600.0 seconds

Spatial Co-ordinates

Latitude	56.68667 N ( 56° 41.2' N )
Longitude	5.32133 W ( 5° 19.3' W )
Positional Uncertainty	0.05 to 0.1 n.miles
Minimum Sensor or Sampling Depth	4.0 m
Maximum Sensor or Sampling Depth	4.0 m
Minimum Sensor or Sampling Height	22.0 m
Maximum Sensor or Sampling Height	22.0 m
Sea Floor Depth	26.0 m
Sea Floor Depth Source	DATAHEAD
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 CODE	Rank	Units	Title
AADYAA01	1	Days	Date (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ01	1	Days	Time (time between 00:00 UT and timestamp)
LCDAEL01	1	Degrees True	Direction (towards) of water current (Eulerian measurement) in the water body by in-situ current meter and correction to true North
LCSAEL01	1	Centimetres per second	Speed of water current (Eulerian measurement) in the water body by in-situ current meter

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

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 Doppler current sensors 4100, 4100R, 4100A and 4100RA

The Aanderaa 4100 current sensor is a rugged, true vector averaging sensor designed to measure current speed and direction in the ocean. Four transducers transmit short pulses (pings) of acoustic energy along narrow beams and receive the backscattered signals from particles in the water. The Doppler shift of the backscattered signal, coupled with data from the internal compass, allows the instrument to determine the current speed and direction. Current measurements are compensated for tilt by the use of an electrolytic tilt sensor whose accuracy is proportional to the square root of the number of pings in a measuring interval. Temperature is measured using a temperature dependent crystal-oscillator-circuit.

Three additional models are available: 4100R, 4100A and 4100RA. These operate in the same manner as the standard 4100, but there are some differences in specifications, as detailed below:

4100R: higher ping rate than 4100; uses RS232 communication instead of SR10; can be configured to output data either automatically or when polled via the RS232 line.
4100A: current speed range higher than the 4100.
4100RA: current speed range higher than the 4100R.

Other specifications are common to all models.

Specifications

Acoustic frequency	2 MHz
Beam angle	± 1° (main lobe)
Depth capability	300 m
Operating temperature	-10 to 50°C
Ping rate	4100: 10 pings s^-1 in intervals of 2 min or less; 1 ping s^-1 in intervals > 2 min 4100R: selectable from 4 to 1200 pings per minute
Current Speed
Range	4100 and 4100R: 0 to 300 cm s^-1 4100A and 4100RA: 0 to 500 cm s^-1
Resolution	0.1 % full scale
Accuracy	± 0.15 cm s^-1 ± 1 % of reading
Standard deviation	0.55 cm s^-1
Current Direction
Range	0 to 360° magnetic
Resolution	0.35°
Accuracy	± 5° for 0 to 15° tilt ± 7.5° for 15 to 35° tilt
Temperature
Range	-10 to 43°C
Resolution	0.05°C
Accuracy	± 0.08°C
Tilt circuit
Accuracy	± 1.5°
Compass circuit
Accuracy	± 3°
Sensitivity	0.01 ppb
Typical range	0.01 to 230 ppb

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

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
Eastward and Northward current velocity	cm.s^-1	LCDAEL01 and LCSAEL01 (direction and speed)	cm.s^-1 and °	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
Salinity	PSU	PSALPR01	Dimensionless	Not recorded at all moorings

Following transfer to QXF, the data were visually screened using in house BODC software. Any data considered as 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)	2013-04-19
End Date (yyyy-mm-dd)	2013-05-08
Organization Undertaking Activity	Marine Scotland Aberdeen Marine Laboratory
Country of Organization	United Kingdom
Originator's Data Activity Identifier	836
Platform Category	subsurface mooring

Marine Scotland Doppler Current Sensor mooring (836), Loch Linnhe

The Aanderaa Doppler Current Sensor 4100/4290s were located at 56° 41.20' N, 05° 19.28' W in a nominal water depth of 26 m.

The DCS 4100/4290s were deployed on 19th April 2013 by Marine Scotland from MV GlenMhor and recovered on 8th May 2013. Instrumentation details are included in the following table.

Instrument type	Serial Number	Deployment start	Deployment end	Instrument depth (m)	Comments
DCS 4100/4290	121	19-04-2013	08-05-2013	4	Depths are quoted as below the surface at half tide.
DCS 4100/4290	121	19-04-2013	08-05-2013	12	Depths are quoted as below the surface at half tide.

Related Data Activity activities are detailed in Appendix 1

Cruise

Cruise Name	20130419
Departure Date	2013-04-19
Arrival Date	2013-04-19
Principal Scientist(s)	Berit Rabe (Marine Scotland Aberdeen Marine Laboratory)
Ship	MV Glenmhor

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