Metadata Report for BODC Series Reference Number 1903588

• 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

BIOFLAME Cruise RRS James Clark Ross JR20080221 (JR178, JR179) Underway Navigation Data Quality Document

Bathymetry

The multi-beam bathymetry channel (MBANSWCB) is of better quality than the single beam (MBANZZ01). Suspect (M) flags were applied to all instances where dropouts or reflection were identified in the data.

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

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.

BIOFLAME Cruise RRS James Clark Ross JR20080221 (JR178, JR179) Underway Navigation Instrumentation Document

Navigation data were obtained through different instruments, but as the Seatex provides the position information for the multibeam system, it is considered by the originator, as a primary source of data so, unlike the other positioning streams, this stream was processed. Unprocessed data from the different navigation streams is available upon request.

The following table presents the instruments that collected data during the cruise:

BIOFLAME Cruise RRS James Clark Ross JR20080221 (JR178, JR179) Underway Navigation Processing Procedures Document

Originator's Data Processing

Four files with processed data and one file with raw data were received at BODC. Data collection started on 17 February 2008 20:30 hours and ended on 11 April 2008 13:14 hours, however the cruise only started on 21 February 2008. The extra days of data collection before the cruise started will not be included in the final file.

The originator's procedures implemented 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 ships 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.

The processing procedures carried out by the originator include:

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

Files delivered to BODC

* Note that although the filename is EM120, the instrument is actually a EM122

BODC Data Processing

Parameter codes defined in BODC's parameter dictionary were assigned to originator's variables. No unit conversion was applied as the originator's units are equivalent to the units defined on the BODC vocabulary. Data were loaded into BODC's database using established data banking procedures.

jr179_seatex_exactsec

jr179_gyro_exactsec

em120

Position

Processing and screening procedures including checks on positional channels. Speed fails were identified and after flagging the affected data, the positions were interpolated as per BODC's established procedures . Once ALATGP01 and ALONGP01 were considered good, screening was performed on the remainder navigation channels.

Distance run

Distance travelled data were rederived from the position channels.

Ship's velocities

Northward and eastward velocities were derived from ALATGP01 and ALONGP01 and during screening procedures, M flags were applied to anomalous data and N flags to null cycles.

Ship's orientation

HEADCM01 was screened and M flags applied to cycles were sudden changes in ship's orientation were considered anomalous.

Bathymetry

Both bathymetry channels were screened and N flags applied to absent data. M flags were applied to all instances where dropouts or reflection were identified in the data. The multibeam channel (MBANSWCB) was considered of higher quality therefore the single beam channel was not included in the final file.

Project Information

BIOFLAME- Biodiversity, Function, Limits and Adaptation from Molecules to Ecosystems

Introduction

This project is part of the BAS GSAC five year research programme. It was funded by NERC and covered a period from 2005 to 2009.

BIOFLAME will study the DNA "fingerprints " of biological evolution to trace the way species adapt to environmental extremes. The methods include high-volume, high-throughput molecular biological approaches, especially DNA sequencing, DNA libraries and micro-array technology on representative samples from the terrestrial and marine ecosystems on and around Antarctica.

BIOFLAME has two components: BIOPEARL (Biodiversity dynamics: Phylogeography, Evolution and Radiation of life) and BIOREACH (Biological Responses to Extreme Antarctic Conditions and Hyper-Extremes) and links with projects and programmes like ACES, CACHE, DISCOVERY2010 and GEACEP.

Scientific Objectives

The main objectives are:

• Understand how the genomes of different species influence their responses to environmental variation and change at the level of individuals, populations, communities and ecosystems
• Find out how the climate change influences biodiversity and affects important ways the ecosystem functions within the Antarctic and globally
• Determine the role of Antarctica and extreme environments in evolutionary change and the development of global biodiversity

Data Availability

Data sets collected during this project are available to the academic community.

Acronyms used in this text:

BAS- British Antarctic Survey

GSAC- Global Science in an Antarctic Context

NERC- Natural Environment Research Council

ACES- Antarctic Climate and the Earth System

CACHE- Climate and Chemistry: forcings, feedbacks and phasings in the Earth System

DISCOVERY2010- Integrating Southern Ocean Ecosystems into the Earth System

GEACEP- Greenhouse to ice-house: Evolution of the Antarctic Cryosphere and Paleoenvironment

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: