Metadata Report for BODC Series Reference Number 1845639

• 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

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 150kHz Vessel mounted ADCP.

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: 1.5

Bottom Track

Maximum altitude (precision <2cm/s): 600m

Echo Intensity Profile

Dynamic range: 80dB
Precision: ±1.5dB

Transducer & 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 in 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

150 kHZ ADCP setup

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:

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

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:

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle: