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Metadata Report for BODC Series Reference Number 1722688


Metadata Summary

Data Description

Data Category Currents -subsurface Eulerian
Instrument Type
NameCategories
Teledyne RDI 300kHz Workhorse Monitor direct-reading ADCP  current profilers
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Dr Penny Holliday
Originating Organization National Oceanography Centre, Southampton
Processing Status QC in progress
Online delivery of data Download not available
Project(s) -
 

Data Identifiers

Originator's Identifier LADCP_083
BODC Series Reference 1722688
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2015-06-15 15:59
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval 5.0 decibars
 

Spatial Co-ordinates

Latitude 56.70898 N ( 56° 42.5' N )
Longitude 6.36526 W ( 6° 21.9' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth 5.0 m
Maximum Sensor or Sampling Depth 125.0 m
Minimum Sensor or Sampling Height 19.0 m
Maximum Sensor or Sampling Height 139.0 m
Sea Floor Depth 144.0 m
Sea Floor Depth Source CTDDATA
Sensor or Sampling Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor or Sampling Depth Datum Approximate - Depth is only approximate
Sea Floor Depth Datum Approximate - Depth is only approximate
 

Parameters

No Parameters for BODC Reference Number = 1722688

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

All casts were processed, although it was noted that casts shallower than 100-200 m often seemed to have problems, usually characterised as giving a profile that was significantly deeper than the true water depth. It is assumed this was due to confusing reflections at the seabed, and recommend that those profiles not be used (Casts 35, 37, 46, 47, 68-75, 79-81, 83). For more information see the cruise report page 35.


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

Instrument Description

The LADCP data were collected using the instrumentation detailed below:

Sensor Model Serial Number Calibration (UT) Comments
LADCP Teledyne RDI high-power Workhorse 300kHz 15288 - LDEO unit, downward looking

One Teledyne RDI Workhorse 300kHz ADCP was mounted on the Sea-Bird 9 11 plus CTD frame pointing downward (downlooker).

Teledyne RDI's Workhorse Monitor ADCP

The Workhorse Monitor acoustic doppler current profler (Teledyne RD Instruments) is a long-range and long-term self contained ADCP. It has a patented four beam signal (300, 600 or 1200 kHz) and a standard depth rating of 200m or 600m. It operates effectively between temperatures of -5°C and 45°C and has a velocity accuracy of ±1% ±5mm/s.

BODC Processing

LDEO processed data were provided by the originator in Matlab and ASCII formats. The LDEO processed data in ASCII format were converted into BODC internal format after discussion with the originator. All data provided were from the downward looking RDI 300 kHz Workhorse ADCP which was in operation at the time. The following table shows how the variables within the ASCII files were mapped to appropriate BODC parameter codes:

Originator's Parameter Name Units Description BODC Parameter Code Units Comments
z m Depth of LADCP bin ADEPZZ01 m -
u m s-1 Eastward velocity LCEWLW01 cm s-1 Units converted from m s-1 to cm s-1 by multiplying by 100.
v m s-1 Northward velocity LCNSLW01 cm s-1 Units converted from m s-1 to cm s-1 by multiplying by 100.
ev m s-1 Uncertainty estimates of LADCP velocity profile ERRVLDCP cm s-1 Units converted from m s-1 to cm s-1 by multiplying by 100.

All reformatted data were visualised using the in-house Edserplo software. Suspect and missing data were marked by adding an appropriate quality control flag.

Note that the more complex LDEO processed data are available on request in Matlab format as well as the unprocessed raw LADCP files.

Originator's Data Processing

Sampling Strategy

A total of 84 LADCP profiles were collected at all CTD stations in order to derive full-depth profiles of ocean velocity, as well as profiles of finestructure vertical shear.

Data processing

Preliminary shipboard processing of the LADCP data was carried out with the LDEO IX LADCP processing software using averaged one Hz ascii CTD data in order to correct the LADCP data for depth and sound speed.

Please refer to Thurnherr (2014) and cruise report for a more detailed processing methodology. However, please be aware that this processing guide is for software versions IX.7 to IX.10 only, and changes have been made between versions which have the potential for significantly changing the solutions.

References

Thurnherr, A. M., 2014. How To Process LADCP Data With the LDEO Software, Versions IX.7 - IX.10.


Project Information


No Project Information held for the Series

Data Activity or Cruise Information

Cruise

Cruise Name DY031
Departure Date 2015-05-29
Arrival Date 2015-06-17
Principal Scientist(s)N Penny Holliday (National Oceanography Centre, Southampton)
Ship RRS Discovery

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NameEllett Line/Extended Ellett Line Station 3G
CategoryOffshore location
Latitude56° 42.48' N
Longitude6° 22.02' W
Water depth below MSL75.0 m

Ellett Line/Extended Ellett Line: Station 3G

Station 3G is one of the fixed CTD stations, which together form The Extended Ellett Line. The line lies between Iceland and the Sound of Mull (Scotland) crossing the Iceland Basin and Rockall Trough via the outcrop of Rockall. As part of this initiative, CTD dips, together with associated discrete sampling of the water column, have typically been carried out annually at this station since September 1996.

Prior to September 1996, Station 3G was part of a shorter repeated survey section, consisting of 35 fixed stations, known as The Ellett Line (originally termed the Anton Dohrn Seamount Section). This line incorporated those stations across the Rockall Trough and Scottish shelf between Rockall and the Sound of Mull and was visited at regular intervals (usually at least once a year) between 1975 and January 1996.

Related Fixed Station activities are detailed in Appendix 1


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
Q value below limit of quantification

Appendix 1: Ellett Line/Extended Ellett Line Station 3G

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
91862CTD or STD cast1977-04-14 12:27:0056.695 N, 6.3416 WRRS Challenger CH6B/77
191408CTD or STD cast1981-07-07 06:45:0056.7016 N, 6.3616 WRRS Challenger CH10/81
193311CTD or STD cast1983-05-23 21:18:0056.7066 N, 6.3666 WRRS Challenger CH7B/83
96750CTD or STD cast1983-08-15 01:08:0056.7083 N, 6.3666 WRRS Challenger CH11/83
348081CTD or STD cast1986-09-27 12:08:0056.7 N, 6.3667 WRRS Frederick Russell FR8/86
316644CTD or STD cast1989-11-25 06:01:0056.7083 N, 6.3667 WRRS Charles Darwin CD44
666957CTD or STD cast2004-07-12 12:20:0056.719 N, 6.402 WFS Poseidon PO314
897043CTD or STD cast2005-10-26 07:11:0056.70856 N, 6.36682 WRRS Charles Darwin CD176
776941CTD or STD cast2006-10-30 03:58:2656.71 N, 6.36767 WRRS Discovery D312
954806CTD or STD cast2009-06-25 03:41:2956.71046 N, 6.36641 WRRS Discovery D340A
1052989CTD or STD cast2010-05-21 17:26:3956.71533 N, 6.36583 WRRS Discovery D351
1897028Water sample data2010-05-21 17:33:0056.71486 N, 6.36539 WRRS Discovery D351
1195284CTD or STD cast2011-05-20 04:06:4656.72017 N, 6.36567 WRRS Discovery D365
1203231CTD or STD cast2012-08-02 10:48:0056.70729 N, 6.36529 WRRS Discovery D379
1220615CTD or STD cast2013-05-23 15:15:1256.7083 N, 6.3666 WRRS James Cook JC086
1371420CTD or STD cast2014-07-17 12:05:3356.7078 N, 6.3667 WRRS James Clark Ross JR20140531 (JR302)
1723606CTD or STD cast2015-06-15 15:58:4056.709 N, 6.3653 WRRS Discovery DY031
1879519Water sample data2015-06-15 16:07:0056.70898 N, 6.36526 WRRS Discovery DY031
1764869CTD or STD cast2016-06-20 06:23:0256.7095 N, 6.365 WRRS Discovery DY052
1765990Currents -subsurface Eulerian2016-06-20 06:23:3056.70948 N, 6.36496 WRRS Discovery DY052
1875162Water sample data2016-06-20 06:28:0056.70948 N, 6.36497 WRRS Discovery DY052