Metadata Report for BODC Series Reference Number 1797654


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 Mr Povl Abrahamsen
Originating Organization British Antarctic Survey
Processing Status banked
Project(s) BAS Long Term Monitoring and Survey
 

Data Identifiers

Originator's Identifier JR272A_LADCP_LDEO_002
BODC Series Reference 1797654
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2012-04-02 20:19
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval 4.0 metres
 

Spatial Co-ordinates

Latitude 60.56489 S ( 60° 33.9' S )
Longitude 41.63261 W ( 41° 38.0' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth 3.86 m
Maximum Sensor Depth 2300.59 m
Minimum Sensor Height 46.4 m
Maximum Sensor Height 2343.14 m
Sea Floor Depth 2347.0 m
Sensor Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum Chart reference - Depth extracted from available chart
 

Parameters

BODC CODE Rank Units Short Title Title
ACYCAA01 1 Dimensionless Record_No Sequence number
ADEPZZ01 1 Metres DepBelowSurf Depth below surface of the water body
LCEWLW01 1 Centimetres per second CurrVelE_ADCP Eastward current velocity (Eulerian) in the water body by lowered acoustic doppler current profiler (ADCP)
LCNSLW01 1 Centimetres per second CurrVelN_ADCP Northward current velocity (Eulerian) 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

RRS James Clark Ross JR20120327 (JR254E, JR257, JR272A) Lowered Acoustic Doppler Current Profiler (LADCP): Data Quality Report

The originator noted data quality issues for Series Reference 1797875 (CTD Cast 21) where interference may have been caused by a change in altimeter (s/n 7742.163162) and for shallow casts deployed in Cumberland Bay Series Reference 1797918 to 1798055 (CTD Cast 26-38) possibly caused by ship board echosounders. Please use data with caution.


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.

RRS James Clark Ross JR20120327 (JR254E, JR257, JR272A) Lowered Acoustic Doppler Current Profiler (LADCP): BODC Processing

The LADCP data were converted from processed tab-delimited text files into BODC internal format using established procedures. The following table shows how the variables within the text files were mapped to appropriate BODC parameter codes:

Originator's Parameter Name Units Description BODC Parameter Code Units Comments
z m Depth below surface of the water body ADEPZZ01 m -
u m s -1 Eastward current velocity (Eulerian) in the water body by lowered acoustic doppler current profiler (ADCP) LCEWLW01 cm s -1 Units converted from m s -1 to cm s -1 by multiplying by 100.
v m s -1 Northward current velocity (Eulerian) in the water body by lowered acoustic doppler current profiler (ADCP) LCNSLW01 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 and screened for suspect and missing data.

Please note that raw LADCP files and processed files using University of Hawaii's LADCP processing software are available on request.

RRS James Clark Ross JR20120327 (JR254E, JR257, JR272A) Lowered Acoustic Doppler Current Profiler (LADCP): Originator's Processing

Sampling Strategy

Lowered Acoustic Doppler Current Profiler (LADCP) data were collected on-board cruise JR20120327. The Teledyne RD Instruments Workhorse Monitor LADCP was installed in a downward looking configuration on the CTD rosette deployed on all 38 CTD cast, however failed for Cast 25 therefore no data file was produced.

Data Processing

The processing steps used by the originator were based on those used for cruises JR139 and JR239. Processing was performed using software from the University of Hawaii (UH) (2008 version) and from Lamont-Doherty Earth Observatory (LDEO) (version 7). The UH software uses the shear from the ADCP profiles to reconstruct a full velocity profile, while the LDEO software uses a matrix inversion technique to optimize stitching the profiles together, reconstructing the CTD package drift in the process.

The processing steps applied are outlined below; please refer to JR20120327 (JR272A) cruise report for further details.

The raw LADCP data files and processed text files from UH and LDEO software were submitted to BODC.


Project Information

BAS Long Term Monitoring and Survey

Introduction

The Long Term Monitoring and Survey project (LTMS) has been running since the British Antarctic Survey (BAS) was created. This project is one of the BAS core projects, with several groups of scientists collecting various types of data e.g biological, geological, atmospheric, among others.

Data collection is achievable through a wide scope of instruments and platforms, e.g. the Antarctic research stations, autonomous instrument platforms deployed on or from BAS research ships, BAS aircrafts, satellite remote sensing and others.

Scientific Objectives

This project was implemented in order to measure change and variability in the Earth system. Its long term duration allows for the monitoring of processes that could be missed in shorter term studies and experiments. The data collected is also used to check and improve the reliability of models used to stimulate and predict the behavior of the Earth system.

The main objectives are:

Data Availability

The data sets obtained through this project are available to the academic community.


Data Activity or Cruise Information

Cruise

Cruise Name JR20120327 (JR254E, JR257, JR272A)
Departure Date 2012-03-27
Arrival Date 2012-04-24
Principal Scientist(s)Claire S Allen (British Antarctic Survey), Hugh Venables (British Antarctic Survey), Margaret J Yelland (National Oceanography Centre, Southampton)
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