Metadata Report for BODC Series Reference Number 1806862

• 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

Kongsberg EA600 Single Beam Echosounder

The 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.

The EA600 replaced the EA500 in 2000.

Specifications

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

Kongsberg Seatex Seapath 320+ Precise Heading, Attitude and Positioning Sensor

The Seapath 320+ is a navigational system that combines two Global Navigation Satellite System (GNSS) receivers with a MRU 5+ inertial sensor to provide high resolution and accuracy positional data. The inertial sensor employs linear accelerometers and unique microelectromechanical systems (MEMS)-type angular rate gyros to provide 0.01 RMS pitch and roll accuracy. The GNSS receivers can use multiple satellite constellations (GPS, GLONASS and Galileo, when available), and combine data from these to improve heading and positional measurements. In case of missing data from one GNSS receiver, the other receiver provides position and velocity, and the inertial sensor provides heading from its internal rate sensors.

The main characteristics are presented below, and the specification sheet can be accessed here Kongsberg Seatex Seapath 320+ .

Specifications

ORCHESTRA RRS James Clark Ross Cruise JR15006 Navigation Instrumentation

Instrumentation

All navigation instruments, except the EA600, fitted in the ship's hull, were located on the ship's monkey island, above the bridge.

The following scientific navigational and bathymetry systems were logging data throughout the cruise.

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.

ORCHESTRA RRS James Clark Ross Cruise JR15006 Underway Document

Content of data series

Data Processing Procedures

Originator's Data Processing

Navigation data

Navigation data were logged continuously during the cruise period and processed by the originator using a combination of Unix and Matlab (R2016a) with scripts provided by Hugh Venables and originally written by mike Meredith. The scripts were modified for this specific cruise. Below is a summary of the scripts used and their main functions:

• get_nav- accesses data from each data stream
• get_ea600- gets hold of ea600 data
• load_daily.m- calls a sequence of scripts, one per instrument, which then reads the the ascii file into matlab and (optionally) saves the data structure as a mat file
• concatenate_gpash.m- concatenates all available nav data into a single record and (optionally) saves it to the disk
• loadea600.m- reads daily ea600 data and outputs it as a mat-file in an organised data structure
• cleanea600.m- calls despike to remove spikes in the data. An interactive editor is then used to remove remaining spikes and other points that look like noise

Files delivered to BODC

Additional files (gpslog_all.mat and tsshrp_all.mat were also submitted to BODC but their data were not transferred as they're not part of standard BODC procedures. All files are available upon request.

BODC Data Processing

The three files from the table above were selected for data banking as they contain the best version of processed position, heading and bathymetry. Data were banked at BODC following standard data banking procedures, including reduction through averaging, checking navigation channels for improbable values, working out speed over ground, and screening the data for anomalous values.

The originator's variables were mapped to appropriate BODC parameter codes as follows:

seatex_all

The file also contained qual, nsat, hdop and altitude parameters, however these were not transferred as they are related to satellite data quality and are not navigation variables.

gyro_all

ea600

All 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.

Position

A check was run on the position data and no gaps were identified.

Ship's velocities

Ship's eastward and northward velocities were calculated from the main latitude and longitude channels.

Distance Run

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

Bathymetry

Missing data were identified throughtout the bathymetry data. These gaps were created by the originator and related to quality control procedures implemented during processing.

Project Information

Ocean Regulation of Climate by Heat and Carbon Sequestration and Transports (ORCHESTRA)

The Ocean Regulation of Climate by Heat and Carbon Sequestration and Transports (ORCHESTRA) is a £8.4 million, five year (2016-2021) research programme funded by the Natural Environment Research Council (NERC). The aim of the research is to to advance the understanding of, and capability to predict, the Southern Ocean's impact on climate change via its uptake and storage of heat and carbon. The programme will significantly reduce uncertainties concerning how this uptake and storage by the ocean influences global climate, by conducting a series of unique fieldwork campaigns and innovative model developments.

Background

ORCHESTRA represents the first fully-unified activity by NERC institutes to address these challenges, and will draw in national and international partners to provide community coherence, and to build a legacy in knowledge and capability that will transcend the timescale of the programme itself.

It brings together science teams from six UK research institutions to investigate the role that the Southern Ocean plays in our changing climate and atmospheric carbon draw-down. It is led by British Antarctic Survey, in partnership with National Oceanography Centre, British Geological Survey, Plymouth Marine Laboratory, the Centre for Polar Observation and Modelling and the Sea Mammal Research Unit.

The oceans around Antarctica play a critical a key role in drawing down and storing large amounts of carbon and vast quantities of heat from from the atmosphere. Due to its remoteness and harsh environment, the Southern Ocean is the world's biggest data desert, and one of the hardest places to get right in climate models. The ORCHESTRA programme will make unique and important new measurements in the Southern Ocean using a range of techniques, including use of the world-class UK research vessel fleet, and deployments of innovative underwater robots. The new understanding obtained will guide key improvements to the current generation of computer models, and will enhance greatly our ability to predict climate into the future.

The scope of the programme includes interaction of the Southern Ocean with the atmosphere, exchange between the upper ocean mixed layer and the interior and exchange between the Southern Ocean and the global ocean.

Further details are available on the ORCHESTRA page.

Participants

Six different organisations are directly involved in research for ORCHESTRA. These institutions are:

• British Antarctic Survey (BAS)
• National Oceanography Centre (NOC)
• Plymouth Marine Laboratory (PML)
• British Geological Survey (BGS)
• Centre for Polar Observation and Modelling (CPOM)
• Sea Mammal Research Unit (SMRU)

GO-SHIP are a third party organisation that, although not directly involved with the programme, will conduct ship based observations that will also be used by ORCHESTRA.

Research details

Three Work Packages have been funded by the ORCHESTRA programme. These are described in brief below:

• Work Package 1: Interaction of the Southern ocean with the atmosphere
  WP1 will use new observations of surface fluxes and their controlling parameters in order to better constrain the exchanges of heat and carbon loss across the surface of the Southern Ocean.

• Work Package 2: Exchange between the upper ocean mixed layer and the interior.
  This work package will combine observationally-derived data and model simulations to determine and understand the exchanges between the ocean mixed layer and its interior.

• Work Package 3: Exchange between the Southern Ocean and the global ocean .
  This WP will use budget analyses of the hydrographic/tracer sections to diagnose the three-dimensional velocity field of the waters entering, leaving and recirculating within the Southern Atlantic sector of the Southern ocean.

• Fieldwork and data collection

  The campaign consists of 12 core cruises on board the NERC research vessels RRS James Clark Ross and RRS James Cook and will include hydrographic/tracer sections conducted across Drake Passage (SR1b), the northern Weddell Sea/Scotia Sea (A23), the northern rim of the Weddell Gyre (ANDREXII) and across the South Atlantic (24S). Section I6S will be performed by GO-SHIP Project Partners. Measurements will include temperature, salinity, dissolved oxygen, velocity, dissolved inorganic carbon, total alkalinity, inorganic nutrients, oxygen and carbon isotopes, and underway meteorological and surface ocean observations including pCO₂.

  Tags will be deployed on 30 Weddel seals and these will provide temperature and salinity profiles that can be used alongside the Argo data.

  Autonomous underwater ocean gliders will conduct multi-month missions and will deliver data on ocean stratification, heat content, mixed layer depth and turbulent mixing over the upper 1 km, with previously-unobtainable temporal resolution. These gliders will be deployed in the Weddell Gyre and the ACC.

  Field campaigns with the MASIN meteorological aircrafts will be conducted flying out of Rothera and Halley research stations and the Falkland Islands. These campaigns will deliver information on key variables relating to air-sea fluxes (surface and air temperature, wind, humidity, atmospheric CO₂, radiation, turbulent fluxes of heat, momentum and CO₂), in different sea ice conditions and oceanic regimes.

  Eart Observation datasets will be used to inform the programme on the properties of the ocean, sea ice and atmosphere and on interactions between them.

  A cluster of 6 deep ocean moorings in the Orkney Passage will collect year round series of AABW temperatre and transport. This work connects to the NERC funded project Dynamics of the Orkney Passage Outflow (DYNOPO).

  The UK Earth System model (UKESM) and underlying physical model will be used to conduct analyses of heat and carbon uptake and transport by the Southern Ocean and their links to wider climate on decadal timescales.

  An eddy-resolving (1/12°) sector model of the ocean south of 30°S with 75 vertical levels, will be built using the NEMO model coupled to the Los Alamos sea ice (CICE) model. The improvements on the ocean boundary layer will be based from the results from the NERC-funded OSMOSIS project and the inclusion of tides.

  20-5 year runs of an adjoint model will be conducted to determine how key forcings and model states affect the uptake and subduction of heat and carbon by 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: