Metadata Report for BODC Series Reference Number 1845627
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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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
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
DY053 75kHz and 150kHz Shipboard ADCP Originator's data processing
The following was taken from the DY053 cruise report.
Data were acquired using the RD Instruments VMDAS software package version 1.46.5.
75 kHZ ADCP setup
Variable | Setting |
---|---|
Number of Bins | 100 |
Bin size | 16m |
Blanking distance | Unknown |
Transducer depth | 5m |
Processing mode | Single-ping mode: narrow-band water-tracking |
Maximum range | 700m |
150 kHZ ADCP setup
Variable | Setting |
---|---|
Number of Bins | 60 |
Bin size | 8m |
Blanking distance | Unknown |
Transducer depth | 5m |
Processing mode | Single-ping mode: narrow-band water-tracking |
Maximum range | 400m |
Post-processing
During the cruise the 75 and 150 kHz data were processed using CODAS version 2015.05.01_python. This new version of CODAS has the advantage to have powerful tools to edit, quality control and display the data. However, the recent version of CODAS no longer supports single ping data in the VMDAS format. It is possible to convert the data into UHDAS format and process them with CODAS, but a lot of processing stages are necessary before being able to process the data in CODAS. Therefore during the cruise, the data were processed in STA format (short time averaging), which was a two-minute average of single ping data.
On a few occasions during the cruise the VMADCP acquisition software stopped generating short and long-term average files (STA and LTA) in real-time. The raw data carried on being collected normally. When this happened the data were re-processed on a different computer, using the same software version (VmDas v.1.46.5) and configuration parameters. 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
Constant velocity heading and amplitude correction calibration values were used for the entire cruise, calculated using data obtained during cruise DY052. The median amplitude correction estimated from the bottom track data for the 75kHz instrument is 1.0149 (std of 0.0064) and the median phase correction is 0.7604° (std of 0.4885°). For the 150kHz instrument, the rotation angle and calibration were estimated to be 0.1721 and 0.9947 respectively. Values are constant because they are based on the physical mounting angle of the transducers.
Processing by BODC of RRS Discovery DY053 Vessel-Mounted ADCP data
The data arrived at BODC in two MStar files representing the data collected from the 75kHz and 150kHz vessel-mounted ADCP instruments from cruise DY053. 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 present in 150kHz data file. Not transferred. |
shipspd | m/s | - | - | Not present in 150kHz data file. 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
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 | DY053 |
Departure Date | 2016-06-29 |
Arrival Date | 2016-07-22 |
Principal Scientist(s) | Stuart A Cunningham (Scottish Association for Marine Science) |
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 |