Metadata Report for BODC Series Reference Number 1173749

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

Data Description

Data Category

Bathythermograph -expendable

Instrument Type

Name	Categories
Lockheed Martin Sippican T-5 XBT probe	bathythermographs; water temperature sensor; Expendable bathythermographs

Instrument Mounting

research vessel

Originating Country

United Kingdom

Originator

Dr Robert Larter

Originating Organization

British Antarctic Survey

Processing Status

banked

Online delivery of data

Download available - Ocean Data View (ODV) format

Project(s)

GRADES

Data Identifiers

Originator's Identifier	T5_00002
BODC Series Reference	1173749

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm)	2008-03-20 17:17
End Time (yyyy-mm-dd hh:mm)	-
Nominal Cycle Interval	1.0 metres

Spatial Co-ordinates

Latitude	67.06112 S ( 67° 3.7' S )
Longitude	105.73501 W ( 105° 44.1' W )
Positional Uncertainty	0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth	1.4 m
Maximum Sensor or Sampling Depth	1830.5 m
Minimum Sensor or Sampling Height	2864.72 m
Maximum Sensor or Sampling Height	4693.83 m
Sea Floor Depth	4695.23 m
Sea Floor Depth Source	GEBCO1901
Sensor or Sampling Distribution	Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor or Sampling Depth Datum	Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum	Chart reference - Depth extracted from available chart

Parameters

BODC CODE	Rank	Units	Title
ACYCAA01	1	Dimensionless	Sequence number
DEPHCV01	1	Metres	Depth (spatial coordinate) relative to water surface in the water body by computation from probe free-fall time using unspecified algorithm
SVELCV01	1	Metres per second	Sound velocity in the water body by computation from temperature and salinity by unspecified algorithm
TEMPET01	1	Degrees Celsius	Temperature of the water body by expendable bathythermograph (XBT)

Definition of Rank
Rank 1 is a one-dimensional parameter Rank 2 is a two-dimensional parameter Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

Problem Reports

No Problem Report Found in the Database

Quality report for James Clark Ross cruise JR20080221 (JR179) XBT data

All casts were screened and M flags applied to cycles where suspect data were identified. The following series/cycles were flagged:

Series reference	Cycles	Comments
46400	2202-2903	Constant/suspect values
46700	1433-2903	Constant/suspect values

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

BODC processing document for XBT data

BODC Processing

The files were sent to BODC in .EDF format, which can be opened with a text editor. No processing was carried out at BODC.

The files were converted to BODC internal format (QXF) using BODC established procedures. There was no need to apply unit conversions as the originator's units were equivalent to the units stored on BODC's vocabulary dictionary.

The following table shows how the variables within the originator's files were mapped to appropriate BODC parameter codes:

Originator's Parameter Name	Units	Description	BODC Parameter Code	Units
Depth	m	Depth below surface of the water body by computation from probe free-fall time using unspecified algorithm	DEPHCV01	m
Temperature	°C	Temperature of the water body by expendable bathythermograph (XBT)	TEMPET01	°C
Sound Velocity	m s^-1	Sound velocity in the water body by computation from temperature and salinity by unspecified algorithm	SVELCV01	m s^-1

Reformatted XBT data were visualised using the in-house graphical editor EDSERPLO. Quality control flags were applied to data as necessary.

Originator's processing document for JR20080221 (JR179) XBT data

A total of four expendable bathymetry thermographs (XBT) were launched, at pre-defined positions, during cruise JR20080221 (JR179) whilst the ship was sailing. The data were transferred to a PC via a USB interface that provided the communication with the XBT launcher.

The data were obtained with T5 Sippican probes and were not processed or calibrated by the originator.

Project Information

Glacial Retreat in Antarctica and Deglaciation of the Earth System (GRADES)

Introduction

GRADES was designed to investigate the state and stability of the Antarctic ice sheet, and its results will contribute to a better prediction of how the WAIS contributes to sea level rise.

Throughout the project ice-sheet models will be developed and tested using newly acquired ice-sheets histories. These models will use satellite data, reconstruct ions of past states of the ice sheet and new data assimilation techniques.

This project has three components:

IMAGE: Inverse Modelling of Antarctica and Global Eustasy
TIGRIS: TargetIngs Glacial Retreat and Ice-stream Systems
QWAD: Quaternary West Antarctic Deglaciations

GRADES has links to other BAS programs like GEACEP, CACHE, ACES and COMPLEXITY.

Objectives:

Understand the role of ice sheet disintegration in global climate change
Assess what is causing the current imbalance in the WAIS
Search for evidence of previous periods of rapid ice loss in the WAIS
Determine the contribution of the WAIS to future sea level change

Data Availability

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

Acronyms used in the text:

WAIS- West Antarctic Ice Sheet
GEACEP- Greenhouse to ice-house: Evolution of the Antarctic Cryosphere and Palaeoenvironment
CACHE- Climate and Chemistry: forcings , feedbacks and phasings in the Earth System
ACES- Antarctic Climate and the Earth System
COMPLEXITY- Natural Complexity Programme

Data Activity or Cruise Information

Cruise

Cruise Name	JR20080221 (JR179)
Departure Date	2008-02-21
Arrival Date	2008-04-11
Principal Scientist(s)	Peter Enderlein (British Antarctic Survey), Robert D Larter (British Antarctic Survey)
Ship	RRS James Clark Ross

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:

Flag	Description
Blank	Unqualified
<	Below detection limit
>	In excess of quoted value
A	Taxonomic flag for affinis (aff.)
B	Beginning of CTD Down/Up Cast
C	Taxonomic flag for confer (cf.)
D	Thermometric depth
E	End of CTD Down/Up Cast
G	Non-taxonomic biological characteristic uncertainty
H	Extrapolated value
I	Taxonomic flag for single species (sp.)
K	Improbable value - unknown quality control source
L	Improbable value - originator's quality control
M	Improbable value - BODC quality control
N	Null value
O	Improbable value - user quality control
P	Trace/calm
Q	Indeterminate
R	Replacement value
S	Estimated value
T	Interpolated value
U	Uncalibrated
W	Control value
X	Excessive difference

SeaDataNet Quality Control Flags