Metadata Report for BODC Series Reference Number 1817128
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 |
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Data Identifiers |
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Time Co-ordinates(UT) |
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Parameters |
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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
RD Instruments- Ocean Surveyor 75kHz Vessel mounted ADCP.
| Long-Range Mode | ||
|---|---|---|
| Vertical Resolution Cell Size3 | Max. Range (m)1 | Precision (cm/s)2 |
| 8m | 520 - 650 | 30 |
| 16m | 560 - 700 | 17 |
| High-Precision Mode | ||
| Vertical Resolution Cell Size3 | Max. Range (m)1 | Precision (cm/s)2 |
| 8m | 310 - 430 | 12 |
| 16m | 350 - 450 | 9 |
1 Ranges at 1 to 5 knots ship speed are typical and vary with situation.
2 Single-ping standard deviation.
3 User's choice of depth cell size is not limited to the typical values specified.
Profile Parameters
- Velocity long-term accuracy (typical): ±1.0%, ±0.5cm/s
- Velocity range: -5 to 9m/s
- # of depth cells: 1 - 128
- Max ping rate: 0.7
Bottom Track
Maximum altitude (precision <2cm/s): 950m
Echo Intensity Profile
Dynamic range: 80dB
Precision: ±1.5dB
Transducer and Hardware
Beam angle: 30°
Configuration: 4-beam phased array
Communications: RS-232 or RS-422 hex-ASCII or binary output at 1200 - 115,200 baud
Output power: 1000W
Standard Sensors
Temperature (mounted on transducer)
- Range: -5° to 45°C
- Precision: ±0.1°C
- Resolution: 0.03°
Environmental
Operating temperature: -5° to 40°C (-5° to 45°C)*
Storage temperature: -30° to 50°C (-30° to 60°C)*
*later instruments have greater range.
Web Page
Further details can be found on the manufacturer's website or in the specification sheet
DY031 Shipboard ADCP Originators data processing
For more detailed information please refer to the cruise report.
Shipboard ADCP data on cruise DY031 were collected by Teledyne RD Instruments - Ocean Surveyor Vessel-Mounted 75 kHz and 150 kHz ADCPs, and acquired from them using the RD Instruments VMDAS software package version 1.46.5.
During the cruise the GDS102 (shallow water navigational echo sounder) was found to be causing interference with the OS150, so it was switched off on day 153.
ADCP setup
| Variable | 75 kHz ADCP Setting | 150 kHz ADCP Setting |
|---|---|---|
| Number of Bins | 60 | 60 |
| Bin size | 16m | 8m |
| Processing mode | Single-ping mode: bottom-tracking and water-tracking | Single-ping mode: bottom-tracking and water-tracking |
| Maximum range | 700m | 400m |
Post-processing
The final processing of data was done using the CODAS (Common Ocean Data Access System) suite of software provided by the University of Hawaii. The processing route can be summarised as copying the raw files, converting them into a working format, merging navigation data, deriving velocities, quality control, and conversion of data to matlab and netcdf files.
Calibration
The PC was running RDI software VmDAS and WinADCP. Gyro heading, GPS Ashtech heading, location and time were fed as NMEA messages into the software which was configured to use the Gyro heading for co-ordinate transformation. The PC software logged the PC clock time, stamped the data (start of each ensemble) with that time, and recorded the offset of the PC clock from GPS time. This offset was then applied to the data in the processing path before merging with navigation.
Processing by BODC of RRS Discovery Vessel Mounted ADCP data
The data arrived at BODC in one MStar file representing the data collected from the vessel mounted ADCP during cruise DY031. The data were reformatted to BODC's internal NetCDF format. The following table shows the mapping of variables within the MStar file to appropriate BODC parameter codes:
| Originator's Variable | Originator's Units | BODC Parameter Code | BODC Units | Comment |
|---|---|---|---|---|
| uabs | cm/s | LCEWAS01 | cm/s | Eastward values are positive |
| vabs | cm/s | LCNSAS01 | cm/s | Northward values are positive |
| uship | m/s | APEWGP01 | cm/s | Conversion *100 applied |
| vship | m/s | APNSGP01 | cm/s | Conversion *100 applied |
| speed | cm/s | - | - | Not transferred |
| shipspd | m/s | - | - | Not transferred |
| depth | metres | DBINAA01 | metres | - |
| lat | degrees | ALATGP01 | degrees | - |
| lon | degrees | ALONGP01 | degrees | Conversion from -180 to 180 applied |
The reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag, missing data by both setting the data to an appropriate value and setting the quality control flag.
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
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 |
