Metadata Report for BODC Series Reference Number 1816162

• 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

RRS James Clark Ross cruise JR17002 navigation quality control report

Bathymetry

The channel has been flagged throughout the cruise where noise in the channel moves away from the baseline bathymetry. Drop outs of zero values were converted to the absent data value. (BODC assessment)

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

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

RRS James Clark Ross cruise JR17002 navigation 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.

RRS James Clark Ross Cruise JR17002 Navigation and Bathymetry Processing Procedures Document

Originator's Data Processing

The navigation and bathymetric data were measured by several different instruments and the data were logged every second to the SCS system and stored in comma separated ACO format. Each instrument logged data to one individual file and the associated header information is stored in TPL files.

The originator's data files exhibited the same common format for the first four columns: Year (yyyy), Julian day.day fraction (days), Julian day (days), day fraction (days). The remaining columns contain the actual data values.

The table below shows the original files delivered to BODC that contained the data in the final data series, along with start and end dates and times of each file.

BODC Data Processing

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

All the reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag.

Position

A check was run on positional data to identify gaps and improbable values (through the calculation of speed). Improbable values were identified where the speed check failed (23/12/2017 22:31:00 and 23/12/2017 23:29:00). They were subsequently removed and the gap interpolated.

Ship velocities

Ship velocities were calculated from the main latitude and longitude channels using standard BODC procedures.

Distance Run

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

GEBCO

GEBCO bathymetry was added to the file using the main latitude and longitude channels.

Bathymetry

Bathymetry data were screened independently as well as against GEBCO bathymetry measurements.

Calibration

No sample calibrations were applied to these data.

Project Information

BAS Long Term Monitoring and Survey

Introduction

The Long Term Monitoring and Survey project (LTMS) has been running since the British Antarctic Survey (BAS) was created. This project is one of the BAS core projects, with several groups of scientists collecting various types of data e.g biological, geological, atmospheric, among others.

Data collection is achievable through a wide scope of instruments and platforms, e.g. the Antarctic research stations, autonomous instrument platforms deployed on or from BAS research ships, BAS aircrafts, satellite remote sensing and others.

Scientific Objectives

This project was implemented in order to measure change and variability in the Earth system. Its long term duration allows for the monitoring of processes that could be missed in shorter term studies and experiments. The data collected is also used to check and improve the reliability of models used to stimulate and predict the behavior of the Earth system.

The main objectives are:

• Topographic survey
• Geosciences survey
• Biological survey and monitoring
• Atmospheric and oceanographic monitoring

Data Availability

The data sets obtained through this project are available to the academic community.

Data Activity or Cruise Information

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Western Core Box

The British Antarctic Survey undertakes cruises to determine krill biomass as part of the ongoing assessment of the status of the marine ecosystem in the region of South Georgia. This unique time series, known as the Western Core Box, which has taken place since 1996 is funded by Natural Environment Research Council (NERC) British Antarctic Survey Long Term Monitoring programme.

The survey area is located in an on and off shelf survery area (figure.1), which comprises of an acoustic grid survey of 8 transects each of 80 km in length. Standard data collection includes underway biological echosounder acoustic transaects, CTD profiles, stratified and targetted RMT8 hauls of macrozooplankton and micronekton and a set of moorings which provide temporal coverage and a year round set of observations.

The specific aims of the WCB are:

• To quantify the interannual variability and long-term change in the mesoscale distribution and abundance of Antarctic krill.
• To quantify the the interannual variability and long-term change in the mesoscale distribution and abundance of other plankton/micronekton.
• To examine interannual varaibility in the context of environmental variability (climate variability).
• To examine prey availiability in the context of predator and fishery demand.

Figure 1. Western Core Box Survey Area (BAS, 2017).

A list of Western Core Box cruises are shown below.

References

British Antarctic Survey (2017). POETS-WCB. Available at: https://www.bas.ac.uk/project/poets-wcb/ [Accessed 2017].

Related Fixed Station activities are detailed in Appendix 1

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:

Appendix 1: Western Core Box

Related series for this Fixed Station are presented in the table below. Further information can be found by following the appropriate links.

If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.