Metadata Report for BODC Series Reference Number 1749222
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 |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Data Identifiers |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Time Co-ordinates(UT) |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Spatial Co-ordinates | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Parameters |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Problem Reports
No Problem Report Found in the Database
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
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
BODC Processing
Data were received at BODC in MStar format files.
The data were reformatted to the internal NetCDF format using BODC-generated Matlab code. The following table shows how the variables within the files were mapped to appropriate BODC parameter codes:
| Originator's variable | Units | Description | BODC Code | Units | Comments |
|---|---|---|---|---|---|
| uabs | cm s-1 | Absolute eastward water velocity (Eulerian) by ADCP | LCEWAS01 | cm s-1 | - |
| vabs | cm s-1 | Absolute northward water velocity (Eulerian) by ADCP | LCNSAS01 | cm s-1 | - |
| time | seconds | - | - | - | Not transferred - recalculated by the transfer |
| lon | degrees | Longitude east (WGS84) using unspecified GPS system | ALONGP01 | degrees | - |
| lat | degrees | Latitude north (WGS84) using unspecified GPS system | ALATGP01 | degrees | - |
| uship | m s-1 | Eastward velocity (over ground) of measurement platform by Ashtech GPS | APEWAS01 | cm s-1 | conversion: multiply by 100 |
| vship | m s-1 | Northward velocity (over ground) of measurement platform by Ashtech GPS | APNSAS01 | cm s-1 | conversion: multiply by 100 |
| depth | metres | ADCP bin depth (bottom of bin) | DBINAA01 | metres | - |
| decday | days | - | - | - | Not transferred - recalculated by the transfer |
| speed | cm s-1 | Absolute water speed (Eulerian) by ADCP | LCSAAS01 | cm s-1 | derived from uabs and vabs |
| shipspd | m s-1 | Ship speed over the ground | APSAZZ01 | m s-1 | derived from uship and vship |
Following transfer the data were screened using BODC in-house visualisation software. Suspect data values were assigned the appropriate BODC data quality flag. Missing data values, where present, were changed to the missing data value and assigned a BODC data quality flag
Originator's Data Processing
Instrument Description
There are two Vessel Mounted Acoustic Doppler current profilers (ADCPs) on DY054; the 150 kHz and the 75 kHz. The 75kHz instrument is a Teledyne RDI Ocean Surveyor 75 (serial number 1813) using VMDas version 1.46.5.
Sampling strategy
During the cruise the 75 kHz data were processed every day, using CODAS version 2015.05.01_python. The median amplitude correction estimated from the bottom track data is 1.0149 (standard deviation of 0.0064) and the median phase correction is 0.7604° (std of 0.4885°). See the cruise report for further information.
The processed MStar data, together with the raw data, were supplied to BODC for banking.
Project Information
UK - Overturning in the Subpolar North Atlantic Programme (UK-OSNAP) Programme
UK-OSNAP is part of an international collaboration to establish a transoceanic observing system in the subpolar North Atlantic. The aim is to quantify and understand the Subpolar Gyre's response to local and remote forcing of mass, heat and freshwater fluxes, within the conceptual framework of the Atlantic Meridional Overturning Circulation (AMOC).
UK-OSNAP is developing a new observing system to provide a continuous record of full-depth, trans-basin mass, heat, and freshwater fluxes. Combining these sustained measurements with innovative modelling techniques will enable the project to characterise the circulation and fluxes of the North Atlantic Subpolar Gyre.
UK-OSNAP is funded by the Natural Environment Research Council (NERC). The project is led by the National Oceanography Centre (NOC) with partners in the University of Liverpool, the University of Oxford and the Scottish Association for Marine Science (SAMS). It is a part of international OSNAP that is led by USA and includes 10 further partner groups in Canada, France, Germany, the Netherlands and China. The project involves fieldwork at sea and model studies.
The OSNAP observing system consists of two legs: one extending from southern Labrador to the southwestern tip of Greenland across the mouth of the Labrador Sea (OSNAP West), and the second from the southeastern tip of Greenland to Scotland (OSNAP East). The observing system also includes subsurface floats (OSNAP Floats) in order to trace the pathways of overflow waters in the basin and to assess the connectivity of currents crossing the OSNAP line.
NERC have added an extension to UK-OSNAP, until October 2024. This will result in the UK-OSNAP-Decade: 10 years of observing and understanding the overturning circulation in the subpolar North Atlantic (2014-2024).
Data Activity or Cruise Information
Cruise
| Cruise Name | DY054 |
| Departure Date | 2016-07-27 |
| Arrival Date | 2016-08-17 |
| 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 |
