Metadata Report for BODC Series Reference Number 1890251

• 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 XBT: Data Quality Report

XBT depth profiles extended to the full length of the wire of 1830.5m for Lockheed Martin Sippicon T-5 probes.

Flags were applied where the instrument kept recording data values beyond the bottom seafloor. Bottom seafloor depths have been determined where possible by comparing GEBCO baythmetry chart readings and echosounder readings available from the cruise underway data to aid decision making. Additional flags were applied to noisy data. Please use the flagged data series below with caution.

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

Instrument description

Lockheed Martin Sippican T-5 XBT Probe

The Expendable Bathythermograph system uses a sea water ground. As soon as an electrode within the nose of the expendable probe makes contact with the water, the circuit is complete and temperature or sound velocity data can be telemetered to the ship-board data processing equipment. The T-5 XBT Probe can be used within a maximum depth of 1830 m, with a rated ship speed of 6 knots and has a vertical resolution of 65 cm.

Manufacturer specifications can be found here

RRS James Clark Ross Cruise JR17002 XBT: BODC Processing

BODC Processing

Files were submitted to BODC in .edf format, which can be opened in a text editor. The .edf file contained depth, temperature, sound velocity and resistance data. Additional metadata was also stored in the header of the file such as deployment time, latitude, longitude, probe type, terminal depth, depth coefficients, constant salinity value used to derive sound velocity.

Files were reformatted to BODC internal NetCDF file format using established procedures and were screened for quality control purposes using internal software Edserplo. No conversions were applied to originator data values. Originator variable were mapped to appropriate BODC parameter codes for standardisation purposes, the below table summarises this.

Original dataset which includes the resistance data channel is available upon request.

RRS James Clark Ross Cruise JR17002 XBT: Originator's Processing

Originator's Sampling Protocol

A total of 25 Lockheed Martin Sippican T-5 Expendable Bathythermographs (XBTs) were deployed to profile the water column on transects at predefined location which has been done on previous surveys in the Western Core Box (WCB).

Each deployment was made using a launcher in which the expendable probe was mounted before deployment. When the probe was locked in position, an electrical connection was made between the probe and recorder. An operator then confirmed that the ship-based recording programme was ready for launch. Following the launch of the probe, copper wire de-reeled from inside the launch canister as well as inside the probe to compensate for ship movement. As the probe descended through the water column, depth and temperature data were recorded and displayed in real time (the design of the probe with precision weighting and spin-stabilisation allows a predictable rate of descent and therefore a depth accuracy of 2%). When the probe reached the sea floor (if shallower than the length of wire), the wire was cut. In deeper water the wire de-reeled to its full length, then dropped into the water column or cut.

Originator's Processing

Data were recorded and displayed in real-time using Sea-Air Systems software WinMK21 v2.13, MIK21COEF v2.9.1, MK21AL v2.14.1. Pre-launch of XBT deployments, metadata were entered into the software and checks were made to ensure the PC time was synced to ship time (GMT). Output files were stored in .edf format, an ASCII output of profile 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.