Metadata Report for BODC Series Reference Number 1902211

• 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

DISCOVERY 2010 Cruise RRS James Clark Ross JR20071230 (JR177, JR205, JR207) Underway Navigation Data Quality Document

Position

A gap in ALATGP01 and ALONGP01 was identified from 15 February 2008 20:43 hours to 15 February 2008 20:45 hours. These cycles were flagged and positions were recomputed by linear interpolation with NAVINT. Position data spans from 30 December 2007 00:00 hours to 15 February 2008 23:58 hours.

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 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

Furuno GPS/WAAS Navigator GP32

The GP32 is an advanced GPS navigator with a Wide Area Augmentation System (WAAS) receiver which can receive up to 12 discrete GPS channels, all-in-view, and also has DGPS capabilities.

The WAAS applies correction data by means of geostationary satellites. The reference stations on earth monitor the GPS constellation and route GPS error data to the WAAS satellite via the master earth station.

This equipment is comprised of a compact unit designed for coastal activities with several display modes, e.g. Plotter, Nav Data, Steering, Highway, Speedometer and two other costumisable modes. The data can be viewed in WGS-84 or other geodetic systems.

Specifications

The equipment's specification sheet can be accessed Furuno GP32

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.

DISCOVERY 2010 Cruise RRS James Clark Ross JR20071230 (JR177, JR205, JR207) Underway Navigation Instrumentation Document

The following scientific navigational and bathymetry systems were fitted:

DISCOVERY 2010 Cruise RRS James Clark Ross JR20071230 (JR177, JR205, JR207) Underway Navigation Processing Procedures Document

Originator's Data Processing

Data processing was done by the originator in Unix and Matlab using modified versions of programs developed by Mike Meredith (BAS) and then read over into netCDF format. Procedures included data loading and visual checks for the positioning streams.

The originator sent 94 files with processed data, including: ship's position, north and eastward velocities, course and speed made good, travelled distance, echosounder bathymetry and ship's heading.

Files delivered to BODC

BODC Data Processing

The files mentioned 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 final file contains data from 30 December 2007 18:04 to 16 December 2007 00:00.

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

bestnav001 to bestnav047

The file also contained vn, ve, cmg, smg, dist_run v_minus_1, however these parameters were not transferred as they were derived by the originator or could be extracted from a more accurate source.

gyro001 to gyro047

JR177_alldataCal_1min

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

A gap in ALATGP01 and ALONGP01 was identified from 15 February 2008 20:43 hours to 15 February 2008 20:45 hours. These cycles were flagged and positions were recomputed by linear interpolation with NAVINT. Position data spans from 30 December 2007 00:00 hours to 15 February 2008 23:58 hours.

Original travelled distance data had a gap so a new channel was created with NAVINT from ALATGP01 and ALONGP01. N flags were applied to null data in HEADCM01 and MBANSWCB. M flags were applied to several cycles in APDAGP01 when changes in course were considered anomalous.

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 cruise period.

Bathymetry

Bathymetry data from the multibeam were loaded and screened. No other flags were applied to the data during screening.

Project Information

DISCOVERY 2010

DISCOVERY 2010 will investigate and describe the response of an ocean ecosystem to climate variability, climate change and commercial exploitation. The programme builds on past studies by BAS on the detailed nature of the South Georgia marine ecosystem and its links with the large-scale physical and biological behaviour of the Southern Ocean.

The aim is to identify, quantify and model key interactions and processes on scales that range from microscopic life forms to higher predators (penguins, albatrosses, seals and whales), and from the local to the circumpolar.

Objectives

Assess the links between the status of local marine food webs and variability and change in the Southern Ocean. Develop a linked set of ecosystem models applying relevant marine physics and biology over scales from the local to that of the entire Southern Ocean.

Relevance to Global Science

Ocean ecosystems play a crucial role in maintaining biodiversity, in depositing carbon into the deep ocean, and as a source of protein for humans. However, fishing and climate change are having significant and often detrimental effects. To predict the future state of ocean ecosystems we must develop computer models capable of simulating biological and physical processes on a range of scales from the local to an entire ocean. Developing such predictive models is crucial to the sustainable management of world fisheries and requires integrated analyses of the way whole ecosystems work. DISCOVERY 2010 aims to take this work forward and at the same time help manage the South Georgia and South Sandwich Islands maritime zone. We will do this through providing information on the state of the ecosystem to the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), the international body that manages sustainable fishing in the Southern Ocean.

Delivering the Results

DISCOVERY 2010 will undertake an integrated programme of shipboard and land-based field studies of the marine food web, combined with modelling. We will pay particular attention to critical phases in the life cycles of key species, and to examining interactive effects in food webs. Interacting biological and physical processes will be modelled across a range of spatial scales to significantly improve our representation of the ocean ecosystem, upon which sustainable management and the prediction of future climate change can be based. DISCOVERY 2010 will link to BIOFLAME, ACES, and COMPLEXITY, two international programmes, and to a collaborative programme with the University of East Anglia on the role of the Southern Ocean in the global carbon cycle.

Component Projects

• DISCOVERY-OEM: Ocean Ecosystems and Management
• DISCOVERY-FOOD-WEBS: Scotia Sea FOOD-WEBS
• DISCOVERY-FLEXICON: FLEXIbility and CONstraints in life histories
• DISCOVERY-CEMI: Circumpolar Ecosystems; Modelling and Integration

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: