Metadata Report for BODC Series Reference Number 674472

• 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 75kHz 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: 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

RRS Discovery Cruise 298 75 kHz VMADCP processing

This document contains extracts from the D298 cruise report.

Configuration

The 75 kHz ADCP on board the RRS Discovery is an Ocean Surveyor narrow band phased array VMADCP with a 30 degree beam angle. It is mounted in the hull in a second water chest 4.15 m forward and 2.5 m to the starboard of the 150 kHz well which is situated 1.75 m to the port of the keel and 33 m aft of the bow at a depth of approximately 5 m. The VMADCP was configured with 60 bins of 16 m thickness and a blank beyond transmit of 8 m.

Data Originator's Processing

• Data acquisition

  Data was logged on a PC using RDI data acquisition software (version 1.3). Data were written by this software to a number of output files which were transferred to a UNIX workstation for further processing.

  Data were processed using the following scripts:

  • surexec0: data read into PSTAR format from raw RDI binary file; Water track velocities written into 'sur' files and bottom track into 'sbt' files whilst in bottom track mode; Velocities scaled to cm/s and amplitudes by 0.45 into db; Time variable corrected to by combining GPS and the PC times; set the depth of each bin.

  • surexec0b: take a sequence of files created by surexec0, append then together and extract data spanning a complete day.

    surexec1: data edited according to status flags (status flag equal to 1 is bad data); edit on percent good variable; move ensemble time to the end of its interval.

  • surexec2: merged data with Ashtech-gyro difference file and correct heading.

  • surexec3: calibrated velocities by scaling by factor A and rotating by angle phi.

  • surexec4: calculated absolute velocities by merging with navigation data (bestnav) and removing the ship's velocity over the ground from the ADCP data.

• Calibration

  Calibration was undertaken by choosing good input data by visual inspection of the data. Data were included in the averaging if they occurred in a consecutive sequence of records which involved stable heading, Ashtech correction and ship's speed. All available bottom track data from 28th to 29th August 2005 on the Greenland Shelf were used.

  The resulting calibration values were;

  • A = 1.002
  • phi = 0.59

BODC post-processing and screening

• Reformatting

  The data were converted from PSTAR format into BODC internal format (QXF) to allow use of in-house visualisation tools.

• Screening

  Reformatted data were visually checked using the in-house editor EDSERPLO. No data values were edited or deleted. Flagging was achieved by modification of the associated quality control flag to 'M' for suspect values and 'N' for nulls.

• Banking

  Once quality control screening was complete, the data were archived in the BODC National Oceanographic Database and the associated metadata were loaded into an ORACLE Relational Database Management System.

References cited

Bacon, S., (2006). RRS Discovery Cruise D298, 23 Aug - 25 Sep 2005. Cape Farewell and Eirik Ridge. National Oceanography Centre, Southampton.

Available - Cruise D298 Report

Project Information

Rapid Climate Change (RAPID) Programme

Rapid Climate Change (RAPID) is a £20 million, six-year (2001-2007) programme of the Natural Environment Research Council (NERC). The programme aims to improve our ability to quantify the probability and magnitude of future rapid change in climate, with a main (but not exclusive) focus on the role of the Atlantic Ocean's Thermohaline Circulation.

Scientific Objectives

• To establish a pre-operational prototype system to continuously observe the strength and structure of the Atlantic Meridional Overturning Circulation (MOC).
• To support long-term direct observations of water, heat, salt, and ice transports at critical locations in the northern North Atlantic, to quantify the atmospheric and other (e.g. river run-off, ice sheet discharge) forcing of these transports, and to perform process studies of ocean mixing at northern high latitudes.
• To construct well-calibrated and time-resolved palaeo data records of past climate change, including error estimates, with a particular emphasis on the quantification of the timing and magnitude of rapid change at annual to centennial time-scales.
• To develop and use high-resolution physical models to synthesise observational data.
• To apply a hierarchy of modelling approaches to understand the processes that connect changes in ocean convection and its atmospheric forcing to the large-scale transports relevant to the modulation of climate.
• To understand, using model experimentation and data (palaeo and present day), the atmosphere's response to large changes in Atlantic northward heat transport, in particular changes in storm tracks, storm frequency, storm strengths, and energy and moisture transports.
• To use both instrumental and palaeo data for the quantitative testing of models' abilities to reproduce climate variability and rapid changes on annual to centennial time-scales. To explore the extent to which these data can provide direct information about the thermohaline circulation (THC) and other possible rapid changes in the climate system and their impact.
• To quantify the probability and magnitude of potential future rapid climate change, and the uncertainties in these estimates.

Projects

Overall 38 projects have been funded by the RAPID programme. These include 4 which focus on Monitoring the Meridional Overturning Circulation (MOC), and 5 international projects jointly funded by the Netherlands Organisation for Scientific Research, the Research Council of Norway and NERC.

The RAPID effort to design a system to continuously monitor the strength and structure of the North Atlantic Meridional Overturning Circulation is being matched by comparative funding from the US National Science Foundation (NSF) for collaborative projects reviewed jointly with the NERC proposals. Three projects were funded by NSF.

A proportion of RAPID funding as been made available for Small and Medium Sized Enterprises (SMEs) as part of NERC's Small Business Research Initiative (SBRI). The SBRI aims to stimulate innovation in the economy by encouraging more high-tech small firms to start up or to develop new research capacities. As a result 4 projects have been funded.

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: