Metadata Report for BODC Series Reference Number 1743945

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 Jon Watkins

Originating Organization

British Antarctic Survey

Processing Status

banked

Online delivery of data

Download available - Ocean Data View (ODV) format

Project(s)

Data Identifiers

Originator's Identifier	T5_00029
BODC Series Reference	1743945

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm)	2009-12-27 07:07
End Time (yyyy-mm-dd hh:mm)	-
Nominal Cycle Interval	0.7 metres

Spatial Co-ordinates

Latitude	54.15172 S ( 54° 9.1' S )
Longitude	38.46467 W ( 38° 27.9' W )
Positional Uncertainty	0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth	0.0 m
Maximum Sensor or Sampling Depth	293.6 m
Minimum Sensor or Sampling Height	-
Maximum Sensor or Sampling Height	-
Sea Floor Depth	-
Sea Floor Depth Source	-
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	Unspecified -
Sea Floor Depth Datum	-

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

Data Quality Report

During visual screening procedures M flags were applied to suspect values identified on the following series:

Series Reference	Comments
1743632	From cycle 2238 to end of cast
1743644	From cycle 2062 to end of cast
1743681	From cycle 1264 to end of cast
1743693	From cycle 526 to end of cast
1743700	From cycle 623 to end of cast
1743761	From cycle 733 to end of cast
1743797	From cycle 802 to end of cast
1743804	From cycle 336 to end of cast
1743816	From cycle 788 to end of cast
1743828	From cycle 329 to end of cast
1743841	From cycle 176 to end of cast
1743853	From cycle 1531 to end of cast
1743921	From cycle 1257 to end of cast
1743933	From cycle 305 to end of cast
1743957	Flagged cycles 44-152, 187-401 and from 641 to end of cast
1743969	From cycle 2092 to end of cast
1743970	Flagged the whole cast
1743994	Flagged the whole cast
1744008	Flagged the whole cast
1744021	Flagged the whole cast
1744033	Flagged the whole cast
1744045	From cycle 371 to end of cast
1744057	From cycle 333 to end of cast
1744069	From cycle 1803 to end of cast

Possible causes for the anomalous data can be due to wire snapping or probe hitting the sea floor. The originator reported that 5 XBT's collected data despite not being deployed, this was due to a malfunction in the XBT gun.

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

Originator's processing document for JR20091212 (JR228) XBT data

Sampling strategy

39 Sippican T5 Expendable Bathythermographs probes (XBT) were launched whilst the ship was sailing at 6 knots. The data were transferred to a PC via a USB interface that provided the communication with the XBT launcher.

Data Processing

When data were exported, a noise reduction procedure was applied. The noise threshold was of 3.0. Sound Velocity was calculated by assuming the following salinities:

Series Reference	Salinity
1743632	33.95
1743644	34
1743656	33.88
1743668	33.86
1743681	33.9
1743693	33.84
1743700	33.85
1743712	33.85
1743724	33.85
1743736	33.96
1743748	33.97
1743761	33.97
1743773	34
1743785	33.8
1743797	33.84
1743804	33.83
1743816	33.82
1743828	33.82
1743841	33.8
1743853	33.84
1743865	33.96
1743877	33.96
1743889	33.87
1743890	33.95
1743908	33.85
1743921	33.77
1743933	33.78
1743945	33.83
1743957	33.83
1743969	33.8
1743970	33.78
1743982	33.78
1743994	33.8
1744008	33.8
1744021	33.8
1744033	33.8
1744045	33.8
1744057	33.8
1744069	31.9

Processing by BODC of RRS James Clark Ross JR20091212 (JR228) XBT data

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

The reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag, and missing data by setting the data to an appropriate value and applying the quality control flag.

Project Information

No Project Information held for the Series

Data Activity or Cruise Information

Cruise

Cruise Name	JR20091211 (JR228)
Departure Date	2009-12-11
Arrival Date	2009-12-30
Principal Scientist(s)	Jonathan L Watkins (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