Metadata Report for BODC Series Reference Number 2207230

• 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

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.

If the Information Provider does not provide a specific attribution statement, or if you are using Information from several Information Providers and multiple attributions are not practical in your product or application, you may consider using the following:

"Contains public sector information licensed under the Open Government Licence v1.0."

Narrative Documents

DY040 Underway Document

Cruise details

Kongsberg EA640 Single Beam Echosounder

The EA640 single beam echosounder comprises a standard EA600 (fitted with a standard transducer) and an additional, non-standard 10 kHz transducer.

The standard EA600 is a single beam echosounder with full ocean depth capability designed for bathymetric surveys. It measures water depth by monitoring the travel time of an acoustic signal that is transmitted from the ship, reflected off the seabed and received back at the ship.

The main components of the system are hull-mounted transducers linked to general purpose transceivers (GPTs). Up to four GPTs, each controlling one or more transducers, may be operated simultaneously. The GPT generates a signal, which is transmitted into the water column as an acoustic pulse by the transducer array, and the returning echo is recorded by the GPT. GPTs are in turn linked to a combined display and processor, where adjustments (such as sound-speed corrections) may be applied to the data. Available frequencies span from 12 to 710 kHz, and each GPT may operate at a separate frequency. A variety of transducers is available for water depths up to 11,000 m.

The EA600 stores all data internally but has a USB port which allows the possibility of connecting a CD-ROM/DVD drive to read and write the data. All echo data can be stored as files: bitmap, sample, depth or sidescan data.

In deeper waters, the EA600 supports a multipulse function, allowing for a higher pinger rate. While on passive mode, the pinger is normally attached to a device, with the purpose of tracking and displaying its current depth.

Specifications for a standard EA600 echosounder

Further details can be found in the manufacturer's specification sheet for the standard EA600 system.

Kongsberg EM122 12kHz Multibeam Echosounder

The EM122 is designed to perform seabed mapping to full ocean depth with a high resolution, coverage and accuracy. Beam focusing is applied both during reception and transmission. The system has up to 288 beams/432 soundings per swath with pointing angles, which are automatically adjusted according to achievable coverage or operator defined limits.

This model uses both Continuous Wave and Frequency Modulated sweep pulses with pulse compression on reception, in order to increase the maximum useful swath width. The transmit fan is split in several individual sectors, with independent active steering, in order to compensate for the vessel movements.

In multiplying mode, two swaths per ping cycle are generated, with up to 864 soundings. The beam spacing is equidistant or equiangular and the transmit fan is duplicated and transmitted with a small difference in along track tilt, which takes into account depth coverage and vessel speed, to give a constant sounding separation along track. In high density mode, more than one sounding per beam can be produced, such that horizontal resolution is increased and is almost constant over the whole swath.

The EM122 transducers are modular linear arrays in a Mills cross configuration with separate units for transmit and receive. If used to deliver sub-bottom profiling capabilities with a very narrow beamwidth, this system is known as SBP120 Sub-Bottom Profiler.

The specification sheet can be accessed here Kongsberg EM122.

Specifications

EM122 versions

DY040 Underway Navigation Instrumentation

Instrumentation

The following scientific navigational and bathymetric systems were fitted.

Sperry Marine MK-37 Gyrocompass

A family of instruments that contain a controlled gyroscope which seeks and aligns itself with the meridian and points to true north. They use the properties of the gyroscope in combination with the rotation of the earth and the effect of gravity. The effects of varying speed and latitude are compensated for by the use of manually operated controls. Models MOD I, MOD O, MOD D, MOD D/E are all with an analog output Step or/and Syncro. MOD VT is the latest model with NMEA Data output as well.

Further specifications for MOD VT can be found in the manufacturer's specification document.

Further information for MOD D/E can be found in the user manual.

Trimble Applanix Position and Orientation Systems for Marine Vessels (POSMV)

The Position and Orientation Systems for Marine Vessels (POSMV) is a real time kinematic (RTK) and differential global positioning system (DGPS) receiver for marine navigation. It includes an inertial system that provides platform attitude information. The instrument provides accurate location, heading, velocity, attitude, heave, acceleration and angular rate measurements.

There are three models of Applanix POSMV, the POS MV 320, POS MV Elite and the POS MV WaveMaster. POS MV 320 and POS MV WaveMaster are designed for use with multibeam sonar systems, enabling adherence to IHO (International Hydrographic Survey) standards on sonar swath widths of greater than ± 75 degrees under all dynamic conditions. The POS MV Elite offers true heading accuracy without the need for dual GPS installation and has the highest degree of accuracy in motion measurement for marine applications.

Specifications

POS MV 320

POS MV WaveMaster

POS MV Elite

¹ One Sigma, depending on quality of differential corrections
² Whichever is greater, for periods of 20 seconds or less

Further details can be found in the manufacturer's specification sheet.

DY040 Underway Navigation Data Processing Procedures

Originator's Data Processing

The data were logged by the TECHSAS (TECHnical and Scientific sensors Acquisition System) version 5.7 data logging system which is the main data logging system on NMF-SS operated research vessels. Data were processed daily using the National Oceanography Centre data processing routines into NetCDF files, and these TECHSAS (NetCDF) navigation and bathymetry files provided to BODC were used for BODC processing, in addition to MSTAR files, processed by the originator. Please refer to the DY040 cruise report for more information. The originator corrected the EA640 single beam bathymetry for Carter Area.

Files delivered to BODC

BODC Data Processing

The data were reformatted to the BODC internal format using standard banking procedures, and averaged at 60 second intervals. The following table shows how variables within the files were mapped to appropriate BODC parameter codes:

bst_dy040_01.nc

sim_dy040_01_nav_cordep.nc

em120_dy040_01.nc

All reformatted data were visualised using the in-house EDSERPLO software. Where calibrations had been applied, only the calibrated versions of those parameters were screened. No flags were deemed necessary for navigation parameters, data were good.

Position

A check was run on positional data to identify gaps and improbable values (through the calculation of speed). No speed fails were found. Fifteen gaps were found, each below 3 minutes in duration. Latitude and longitude values during these times were interpolated and assigned a BODC 'T' flag to signal these values were interolated.

Distance Run

Distance run was calculated from the main latitude and longitude channels, starting from the beginning of the file.

GEBCO

GEBCO bathymetry (15 arc-second grid) was added to the file using the main latitude and longitude channels. It was used to screen echo-sounder bathymetry. Bathymetry data tracked GEBCO data very well.

Bathymetry

Bathymetry data were screened independently as well as against GEBCO bathymetry measurements. The EA640 single beam was considered the best source of bathymetric data during DY040 due to the value added by the originator and was retained in the file. The swath bathymetry channel was dropped.

Calibration

No field calibrations were applied to the data at BODC.

Project Information

The Global Ocean Ship-based Hydrographic Investigations Program (GO-SHIP) project document

The Global Ocean Ship-based Hydrographic Investigations Program (GO-SHIP) brings together scientists with interests in physical oceanography, the carbon cycle, marine biogeochemistry and ecosystems, and other users and collectors of ocean interior data to develop a sustained global network of hydrographic sections as part of the Global Ocean / Climate Observing System.

The GO-SHIP Panel was established in 2007 by the IOCCP and CLIVAR to develop a strategy for a sustained global repeat hydrography program as a contribution to the OceanObs09 Conference (September 2009) and to revise the 1994 WOCE hydrographic program manual. Based on community discussions at the OceanObs09 Conference, the Panel recommended the development of a sustained repeat hydrography program to:

• develop formal international agreements for a sustained international repeat ship-based hydrography program, including an internationally-agreed strategy and implementation plan building on the guidelines in the Community White Paper,
• advocate for national contributions to this strategy and participation in the global program,
• provide a central forum for communication and coordination, and
• develop syntheses of hydrographic data, in partnership with national, regional, and global research programs.

The IOCCP and CLIVAR International Project Offices have agreed to provide project office support to this program as it develops.

Project office support for GO-SHIP is provided by the IOC-SCOR International Ocean Carbon Coordination Project (IOCCP) and the Climate Variability and Predictability Project (CLIVAR). Major financial support for this project is provided by the U.S. National Science Foundation through a grant to UNESCO - IOC (OCE - 0715161) and a grant to the Scientific Committee on Oceanic Research (OCE - 0608600) for the IOCCP.

For more information please see the official project website at GO-SHIP

NOCS National Capability

The National Oceanography Centre Southampton National Capability focuses on long term science concerned with basin/decadal variability of the Ocean.

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: