Metadata Report for BODC Series Reference Number 1905534

• 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

Kongsberg Seatex Seapath 200 GPS and Gyrocompass

The Seapath 200 is a highly accurate, real-time heading, attitude and position information system that integrates the best signal characteristics of Inertial Measurement Units (IMU) and Global Positioning System (GPS), using a differential GPS method to acquire this data.

The high-rate motion data is obtained from the Seatex MRU5 inertial sensor and two fixed baseline GPS carrier-phase receivers. The raw data is integrated in a Kalman filter in the Seapath Processing Unit. The IMU contains an accurate linear accelerometer and Bosch Coriolis force angular rate gyros (CFG).

This system is equipped to utilise up to six different DGPS reference stations, it checks for consistency within measurements from the different sensors to ensure reliability and rejects noisy data or reports its inaccuracy. The data is available through various output protocols, RS-232, RS-422 and Ethernet.

This instrument is no longer in production; the main characteristics are presented below, and the specification sheet can be accessed here Kongsberg Seatex Seapath 200 .

Specifications

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.

BAS Polar Science for Planet Earth RRS James Clark Ross Cruise JR20091202 (JR230) Underway Navigation Instrumentation Document

Although the ship has four positioning systems, the Seatex GPS provides the input latitude and longitude for the multibeam positioning, and is considered as the primary source of data. The following scientific systems were fitted:

BAS Polar Science for Planet Earth RRS James Clark Ross Cruise JR20091202 (JR230) Underway Navigation Processing Procedures Document

Originator's Data Processing

The processing procedures, throughout the cruise, consisted of data retrieval from the previous 24h and logging those into subdirectories on the ship's intranet system.

Navigation instruments were located on the ship's monkey island, above the bridge.

Data processing was carried out at BAS on selected data streams. The ship has four positioning systems, but as the Seatex GPS provides the input latitude and longitude for the multibeam positioning, it is considered as a primary source of data, so processing was carried out on this stream but not on the others. These procedures included:

• check for duplicate dates and times
• standardising time
• check for gaps in data
• check data against defined thresholds
• interpolation and flagging
• unit conversion

The originator sent two files with processed ship's heading and position data.

Files delivered to BODC

Bathymetry data were not processed by the originator, however raw data were also transferred and during visualisation, it was clear that the streams did not contain valid data for the cruise period.

BODC Data Processing

The files mentioned above were selected for data banking as they contain the best version of processed position and heading. 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:

jr228_230_seatex_exactsec

jr228_230_gyro_exactsec

BODC's procedures included the transfer of originator's parameters into BODC codes and visual screening in Edserplo. N flags were applied to absent values during the data transfer.

Position

Checks were performed on the position data and no gaps were found in the data. T flags were identified in the originator's data, no further flags were applied as no anomalous values were identified.

Ship's eastward and northward velocities were calculated from the main latitude and longitude channels. M flags were identified on position cycles flagged T by the originator. No further flags were applied.

Distance Run

Distance run was calculated from the main latitude and longitude channels, starting from the beginning of the cruise period. M flags were identified on position cycles flagged T by the originator. No further flags were applied.

Bathymetry

Bathymetry data from both the multibeam and echosounder were loaded and visualised. It was found that the cruise period did not contain valid bathymetry data, therefore this channel was not included in the final file.

Project Information

Polar Science for Planet Earth (PSPE)

Introduction

The PSPE programme is the British Antarctic Survey strategic science framework that extends from April 2009 to March 2013. This programme was created to respond to the Natural Environment Research Council (NERC) strategy from 2007 to 2012, and contributes to a major environmental research programme, Living with Environmental Change (LWEC), which comprises a 10 year partnership between the UK's main organisations that fund, carry out and use environmental research and observations and will improve the country's tools and knowledge to build resilience, mitigate problems and adapt to environmental change.

The PSPE programme will focus on key questions that can be answered by research requiring access to the polar regions, developing research and long term monitoring and survey programmes in the Antarctic but also pursuing new bi-polar and Arctic research opportunities. The support given to the research programmes includes: investment in training, development of scientific skills and expertise, maintenance of the existing research infrastructures (research stations, ships, aircraft and laboratories), development of new techniques to collect, transfer, curate and visualize data from and relating to the polar regions.

PSPE consists of 6 programmes:

• Climate: atmospheric science and processes, including climate modelling
• Chemistry and past climate: quaternary climate including ice cores, lake, sediments, marine sediments and tropospheric chemistry
• Ecosystems: dynamics of polar ecosystems in response to the impacts of climate and fisheries
• Environmental Change and Evolution: the Earth system; geological to upper atmosphere, complexities and scales of interactions, controls on biological evolution
• Ice sheets: ice sheet evolution and flow, ice sheet changes and sea level rise
• Oceans: role of the polar oceans in controlling and influencing the Earth system

Data Availability

The data produced during this project are available to the academic community.

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: