Radio-echo sounding (RES) ice thickness data: LGB traverses 1990-95
Entry ID: LGB_RES_traverse

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Summary
Abstract: The Lambert Glacier Basin (LGB) series of five oversnow traverses were conducted from 1989-95. The ANARE 100 MHz digital ice radar operated from the second traverse (1990/91) and recorded ice thicknesses approximately every 10-15 m along three routes: the 2014 km main traverse track from LGB00 (68.6543 S, 61.1201 E) near Mawson to LGB72 (69.9209 S, 76.4933 E) near Davis; the 516 km upper western offset track (50 km parallel upslope from main route) from LGBUW485 (68.6458 S, 60.0272 E) to LGBUW000 (72.6508 S, 55.9275 E); and the 560 km south western offset track from LGBUW485 to LGBOS01 (76.5152 S, 63.9098 E). RES data for ice thickness measurements constituted a major component in the study of the mass budget and dynamics of the interior Lambert Glacier basin.

Raw data were stored in 200 kb binary files containing 200 x 1024 x 8 bit sample waveforms giving approximately 10 m spacing between ice thickness values, together with a header field describing relevant parameters associated with each 2 km long section of track. Processed data were stored as 2 km averaged ice thickness spreadsheet files (MS Excel), or 100 m spatial resolution EPS files for plotting signal profiles. The data available at the url below are stored in various formats.

Summary data (2 km spatial average) can be obtained from CRC Research Note No.27 'Ice Thicknesses and Surface and Bedrock Elevations from the Lambert Glacier Basin Traverses 1990-95'.

Documents providing archive details of the logbooks are available for download from the provided URL.

This work was completed as part of ASAC projects 3 and 2216.

Related URL
Link: GET DATA
Description: Download point for the data


Link: VIEW PROJECT HOME PAGE
Description: Public information for ASAC project 3


Link: VIEW PROJECT HOME PAGE
Description: Public information for ASAC project 2216


Link: VIEW RELATED INFORMATION
Description: Download point for the catalogue information for the logbooks


Link: VIEW RELATED INFORMATION
Description: Citation reference for this metadata record and dataset


Geographic Coverage
 N: -69.0 S: -77.0  E: 78.0  W: 54.0

Temporal Coverage
Start Date: 1990-11-01
Stop Date: 1995-02-28


Location Keywords
CONTINENT > ANTARCTICA > Lambert Glacier
GEOGRAPHIC REGION > POLAR


Science Keywords
CRYOSPHERE >GLACIERS/ICE SHEETS >GLACIERS    [Definition]
CRYOSPHERE >SNOW/ICE >ICE DEPTH/THICKNESS    [Definition]
SPECTRAL/ENGINEERING >RADIO WAVE    [Definition]


ISO Topic Category
GEOSCIENTIFIC INFORMATION
IMAGERY/BASE MAPS/EARTH COVER
INLAND WATERS


Platform
FIELD SURVEYS    [Information]


Quality
Small gaps in the data arose from loss of signal return in areas of extremely deep ice and/or internal reflections from complex structures within the ice. On a 2 km spatially averaged resolution these gaps have been compensated for by gravity interpolation of ice thicknesses. The ANARE Mk Vb 100 MHz ice radar produced peak power of 3 kW with a pulse duration of 250 ns and repetition rate of 10 kHz. An antenna array of 2 transmit and 4 receive yagis (1 driven element, 2 directors, 1 reflector) was used in 1990/91 and 1992/93, whilst an array of 1 transmit and 2 receive corner reflectors were used in 1993/94 and 1994/95. The radar unit operated from a sled-mounted van towed by a Caterpillar D7H tractor, moving at an average speed of 5 km/hr. Linear and logarithmic amplifier stages passed the return signal (using a 3 ms transmit pulse suppression technique) to a digital storage oscilloscope (DSO), which continuously averaged incoming pulses before transmitting to file every 5-10 s (as preset). The averaging resulted in a better than 20 dB signal-to-noise- ratio. Signal propagation delay times were converted to ice thicknesses assuming a velocity of 169 m/microsecond with no firn correction. A header section was attached to file containing information including navigational GPS (pseudo-range) positioning for each 10 m averaged data point. A semi- automated data processing routine produced RES profiles as EPS files for printing, or ASCII files for importing into spreadsheet programs (MS Excel) for further analysis. The data have been checked externally with 2 km spaced gravity readings and internally by repeat measurement over several sections of traverse track. Ice thickness values were accurate to within 20 m over 2000 m depth. Geographic locations for which ice thickness values applied were navigational GPS (30-100 m accuracy) constrained to overnight LGB station geodetic GPS fixes (1-5 m horizontal) every 30 km along the main traverse route, and of similar accuracy for the parallel offset lines.


Access Constraints
The data are available from the url given below. Documents providing archive details of the logbooks are also available for download from the provided URL.


Use Constraints
This data set conforms to the PICCCBY Attribution License
(http://creativecommons.org/licenses/by/3.0/).

Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=LGB_RES_... when using these data.


Keywords
ANTARCTICA
GLACIER
ICE THICKNESS


Data Set Progress
COMPLETE


Originating Center
AAD


Data Center
Australian Antarctic Data Centre, Australia    [Information]
Data Center URL: http://data.aad.gov.au

Data Center Personnel
Name: DATA OFFICER AADC
Phone: +61 3 6232 3244
Fax: +61 3 6232 3351
Email: metadata at aad.gov.au
Contact Address:
Australian Antarctic Division
203 Channel Highway
City: Kingston
Province or State: Tasmania
Postal Code: 7050
Country: Australia



Distribution
Distribution_Media: HTTP
Distribution_Size: 4435 KB
Fees: free

Distribution_Media: HTTP
Distribution_Size: 61 KB
Distribution_Format: pdf
Fees: free


Personnel
IAN ALLISON
Role: TECHNICAL CONTACT
Role: INVESTIGATOR
Phone: +61 3 6226 7648
Fax: +61 3 6226 7650
Email: ian.allison at aad.gov.au
Contact Address:
Australian Antarctic Division
203 Channel Highway
City: Kingston
Province or State: Tasmania
Postal Code: 7050
Country: Australia


DAVE J. CONNELL
Role: DIF AUTHOR
Phone: +61 3 6232 3244
Fax: +61 3 6232 3351
Email: dave.connell at aad.gov.au
Contact Address:
Australian Antarctic Division
203 Channel Highway
City: Kingston
Province or State: Tasmania
Postal Code: 7050
Country: Australia



Creation and Review Dates
DIF Creation Date: 1999-10-07
Last DIF Revision Date: 2014-01-10

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