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Metadata Report for BODC Series Reference Number 1920045


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 Andrew Meijers
Originating Organization British Antarctic Survey
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) DIMES
 

Data Identifiers

Originator's Identifier LADCP_094
BODC Series Reference 1920045
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2014-04-22 13:30
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 53.21498 S ( 53° 12.9' S )
Longitude 48.78337 W ( 48° 47.0' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth 7.8 m
Maximum Sensor or Sampling Depth 2620.4 m
Minimum Sensor or Sampling Height 227.84 m
Maximum Sensor or Sampling Height 2840.45 m
Sea Floor Depth 2848.25 m
Sea Floor Depth Source GEBCO1401
Sensor or Sampling Distribution Sensor fixed with measurements made at multiple depths within a fixed range (e.g. ADCP) - The sensor is at a fixed depth, but measurements are made remotely from the sensor over a range of depths (e.g. ADCP measurements)
Sensor or Sampling Depth Datum Approximate - Depth is only approximate
Sea Floor Depth Datum Chart reference - Depth extracted from available chart
 

Parameters

BODC CODERankUnitsTitle
ACYCAA011DimensionlessSequence number
ADEPZZ011MetresDepth (spatial coordinate) relative to water surface in the water body
ERRVLDCP1Centimetres per secondError velocity of water current in the water body by lowered acoustic doppler current profiler (ADCP)
LCEWLW011Centimetres per secondEastward velocity of water current (Eulerian measurement) in the water body by lowered acoustic doppler current profiler (ADCP)
LCNSLW011Centimetres per secondNorthward velocity of water current (Eulerian measurement) in the water body by lowered acoustic doppler current profiler (ADCP)

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

BODC Data Quality Report

No flags were applied to JR20140308 or JR20140331 LADCP data during screening.


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

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 Data Processing

Lamont-Doherty Earth Observatory (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 following discussion with the originator. All data provided were from the downward looking Teledyne RDI Workhorse 300 kHz 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 Variable Originator's Units BODC Parameter Code BODC Units Comments
z m ADEPZZ01 m -
u m s-1 LCEWLW01 cm s-1 Units converted from m s-1 to cm s-1 by multiplying by 100.
v m s-1 LCNSLW01 cm s-1 Units converted from m s-1 to cm s-1 by multiplying by 100.
ev m s-1 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.

The unprocessed raw LADCP files and the more complex LDEO processed data, in Matlab format, are available on request. Further information on the originator's quality control on the more complex LDEO processed data can be found in the originator's quality control report.

Originator's Data Processing

Instrument description

Two Teledyne RDI Workhorse 300 kHz instruments were mounted on a CTD frame, a downlooker/master (serial number 15060) and an uplooker/slave (serial number 14897).

Sampling strategy

Lowered Acoustic Doppler Current Profiler (LADCP) profiles were attempted at all CTD stations (1 - 119) in order to derive full-depth profiles of ocean velocity, as well as profiles of finescale vertical shear of horizontal velocities. Leg 2 of JR299 includes CTD stations 33 - 119 (87 LADCP profiles).

Data processing

During the cruise, the quality of the JR299 LADCP data was remotely monitored at Lamont-Doherty Earth Observatory (LDEO). All diagnostic plots created during shipboard processing were inspected and suspicious profiles flagged. Preliminary processing was completed using the LDEO LADCP software version IX_6. Range corrections were made using sound speed profiles calculated from the CTD data for each station.

Post cruise, all profiles were re-processed following the same method as on the ship with the most up-to-date version of the LDEO software (IX_11beta). Please refer to the data quality report, cruise report and Thurnherr (2014) for more details about the processing methodology.

References

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


Project Information

Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES) project document

DIMES is a US/UK field program aimed at measuring diapycnal and isopycnal mixing in the Southern Ocean, along the tilting isopycnals of the Antarctic Circumpolar Current.

The Meridional Overturning Circulation (MOC) of the ocean is a critical regulator of the Earth's climate processes. Climate models are highly sensitive to the representation of mixing processes in the southern limb of the MOC, within the Southern Ocean, although the lack of extensive in situ observations of Southern Ocean mixing processes has made evaluation of mixing somewhat difficult. Theories and models of the Southern Ocean circulation have been built on the premise of adiabatic flow in the ocean interior, with diabatic processes confined to the upper-ocean mixed layer. Interior diapycnal mixing has often been assumed to be small, but a few recent studies have suggested that diapycnal mixing might be large in some locations, particularly over rough bathymetry. Depending on its extent, this interior diapycnal mixing could significantly affect the overall energetics and property balances for the Southern Ocean and in turn for the global ocean. The goals of DIMES are to obtain measurements that will help us quantify both along-isopycnal eddy-driven mixing and cross-isopycnal interior mixing.

DIMES includes tracer release, isopycnal following RAFOS floats, microstructure measurements, shearmeter floats, EM-APEX floats, a mooring array in Drake Passage, hydrographic observations, inverse modeling, and analysis of altimetry and numerical model output.

DIMES is sponsored by the National Science Foundation (U.S.), Natural Environment Research Council (U.K) and British Antarctic Survey (U.K.)

For more information please see the official project website at DIMES


Data Activity or Cruise Information

Cruise

Cruise Name JR20140331 (JR272C, JR273B, JR293 Leg2, JR299 Leg2, UKD-5)
Departure Date 2014-03-31
Arrival Date 2014-04-29
Principal Scientist(s)Andrew J S Meijers (British Antarctic Survey)
Ship RRS James Clark Ross

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
Q value below limit of quantification