[Parameters: Topic='LAND SURFACE', Term='TOPOGRAPHY', Variable_Level_1='CONTOURS']
Analysis of East Antarctic drainage basins with altimetric, interferometric, gravity and GPS techniques to determine their state of fluxEntry ID: ASAC_2788
Abstract: Metadata record for data from ASAC Project 2788
See the link below for public details on this project.
This project will reassess the mass balance of Law Dome and a large sector of the Antarctic ice sheet south of Casey by exploiting the time history of change that can be obtained by resurveying historical surface elevation and gravity networks, started in the 1960s. The changes in ... position and gravity from these terrestrial traverses act as important constraints and, in some cases, calibration for recent satellite altimeter missions. Such a reassessment and model improvement should see a significant drop in the current uncertainty of the contribution of the Antarctic ice sheet to global sea level rise.
Historical and recent data over Law Dome has been successfully re-reduced and integrated with recent satellite data over a period spanning 1962 to 2005. These data show that the surface elevation of Law Dome decreased from 1962 to about 1971 and then generally increased till 2005 indicating that ice volumes have recently varied over decadal time spans. The variations that are present within our gravity data set are in agreement with the deep core stratigraphy results from the Law Dome summit. Since our data cover the full extent of Law Dome, we are able to state with good confidence that the changes we see are consistent with climate-related signals where increased precipitation is due to increased atmospheric water vapour. This phenomenon has been reported in the Norwegian Arctic. The detection of these localised complex changes, over decadal time scales , highlights problems associated with interpreting relatively short time scale altimetric measurements.
Start Date: 2007-10-01Stop Date: 2009-03-31
ISO Topic Category
Quality The Dates provided in temporal coverage are approximate only, and represent the beginning and end of the 2007 - 2009 Antarctic seasons.
The latitudes and longitudes provided in spatial coverage are approximate only.
Objective 1 - all available gravity data over a 40yr period has been verified, checked, ... calibrated and adjusted so that we have the most complete reduced gravity dataset for the Law Dome area. All available GPS data has been reduced from that data collected during 2004-05 field season. All available GPS data collected during 2004-05 field season has been reduced. A significant portion of the GPS data has been validated and inter compared using different reduction techniques in order to understand errors particularly in L1 pseudo range data.
This objective is now some 70% complete. The remaining work refers to the deep south lines, generally south of 70 degrees south. The gravity data have been adjusted but not yet navigated for precise position, that is, assigned WGS84 coordinates. The data entry from paper records is the current hurdle.
Objective 2 - A re-occupation of earlier survey control lines was done using GPS in season 2004-05(limited by logistical support), attempts to get back into the field in later seasons have not been possible (priority to the aircraft/runway). Attempts were made in season 07-08 to revisit some of our GPS sites to located and extend poles to save the value of the science for future seasons. This was not possible and/or not successful so if we do future work, the surveys will have to start again as past information is lost. This objective has not been possible due to the lack of field support after the first season. We are now fearful of losing all scientific value from the 2004-2005 data as the deep holes placed to determine horizontal/vertical change are now buried and are likely never to be recovered as the precision of real time location is about 2 meters and their depth will be in excess of 2 meters. The possible exception for recovery may be the 100m borehole placed by the ice core group for us
Objective 3 - a paper has been submitted to the Australian Journal of Earth Sciences (Bailey, Morgan, Lackie) and is currently in review. This paper has now been rejected, principally due to GPS positioning results which were deemed to be too good to be true. We are seeking an alternative journal.
See documentation within the download file for further information.
Access Constraints These data are publicly available for download from the provided URL.
Use Constraints This data set conforms to the PICCCBY Attribution License
Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=ASAC_2788 when using these data.
Data Set Progress
Distribution Media: HTTP
Distribution Size: 420 MB
Distribution Format: text, excel, binary
Role: TECHNICAL CONTACT
Phone: +61 3 6226 2108
Fax: +61 3 6224 0282
Email: Richard.Coleman at utas.edu.au
Centre for Spatial Information Science School of Geography and Environmental Studies University of Tasmania Private Bag 76
Province or State: Tasmania
Postal Code: 7001
Role: DIF AUTHOR
Phone: +61 3 6232 3244
Fax: +61 3 6232 3351
Email: dave.connell at aad.gov.au
Australian Antarctic Division 203 Channel Highway
Province or State: Tasmania
Postal Code: 7050
Watson C., Tregoning P., Coleman R. (2006), Impact of solid Earth tide models on GPS coordinate and tropospheric time series, Geophysical Research Letters, 33, L08306, doi:doi:10.1029/2005GL025538
Extended Metadata Properties
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Creation and Review Dates
DIF Creation Date: 2006-07-27
Last DIF Revision Date: 2014-08-29