Metadata Report for BODC Series Reference Number 1798006
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
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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.
- At the start of each cast, a test script was run on the ADCP to check that everything was working well.
- A BAS standard command file was run. This file should be adapted where necessary for future cruises. Please see the cruise report for an example of the file.
- Raw data and transcript files from each deployment, were downloaded to a laptop in the chemistry lab, and backed up before being saved on the ships directory.
- Navigation files were created. Input: data streams; output .mat files. Then the edexec_startall' script was run to create all of the processed ascii data files within the current directory. m_setup and make_sm were run to create sm.mat.
- CTD files were created. Input: 1Hz processed NetCDF files; output: ASCII files. The linkctd script was modified to create links to the raw files. mk_ctdfile(NNN) script was run in Matlab for each CTD cast.
- Links were created to raw LADCP files by running the linkscript.
- Files were processed using UH software in Matlab. Specific code used is outlined in the cruise report.
- Checks were made to ensure CTDs and LADCP casts were aligned correctly using an algorithm.
- Files were then processed using LDEO software in Matlab. Specific code used is outlined in the cruise report.
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:
- Topographic survey
- Geosciences survey
- Biological survey and monitoring
- Atmospheric and oceanographic monitoring
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 J 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 |
| B | nominal value |
| Q | value below limit of quantification |
