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Antarctic airborne gravity data

Free-Air Gravity Anomalies Over the Thwaites Glacier Catchment, West Antarctica

This airborne free-air gravity dataset over Thwaites Glacier in the Amundsen Sea Embayment of West Antarctica was collected and processed primarily by the Univeristy of Texas at Austin, Institute for Geophysics (UTIG) in the austral summer of 2004-2005. The survey was named AGASEA (Airborne Geophysics of the Amundsen Sea Embayment, Antarctica) and we used a Micro-G LaCoste Air/Sea II gravimeter. Five flights of data were collected during that same Antarctic field season by the British Antarctic Survey and are included in these gridded gravity anomalies and crossover differences. This dataset covers an irregularly-shaped area between Longitudes 135 deg W and 93 deg W and Latitudes 72 deg S and 82 deg S. The data lines were flown at an angle to the northing and easting lines of a polar stereographic projection with true scale at 71 deg S (called ps71). Flight line spacing was a 15 km regular grid with extra lines of data collected at angles to the grid as the opportunity arose (draped lines following glacier flow lines were flown but not included in this gravity dataset because gravity could not be recovered during draped flying).

Files available:

  1. Readme.txt: Documentation file.
  2. utig_agasea_freeairgrv.llg: -Data file of free-air gravity anomalies after standard data processing (Diehl et al., 2008a) and gridding in GMT.
  3. utig_agasea_freeairgrv_crossover_diffs.dat: Data file of crossover differences in the line-based free-air data, calculated before gridding for two points near each other on crossing lines (see Diehl et al. (2008a) for further information).
  4. utig_agasea_freeairgrv.jpg: JPEG image of the data from file #1, projected into polar stereographic 71.
  5. utig_agasea_freeairgrv_crossover_diffs.jpg: JPEG image of data from file #2, projected into polar stereographic 71 and plotted using the location of point 1 (ie. location in columns 1 and 2 and data in column 7). Contours are ice surface elevations from Liu et al. (2001).

Please cite the following reference when using these data:

Diehl, T. M., J. W. Holt, D. D. Blankenship, D. A. Young, T. A. Jordan, and P. Ferraccioli (2008), First airborne gravity results over the Thwaites Glacier catchment, West Antarctica, Geochem. Geophys. Geosyst., 9, Q04011, doi:10.1029/2007GC001878.

Collection and processing of this free-air gravity dataset was funded by the National Science Foundation grant OPP-0230197, the Jackson School of Geosciences and the Geology Foundation at the University of Texas at Austin, the G. Unger Vetleson Foundation, and the UK Natural Environment Research Council.

Contact the author for questions or electronic copies of the paper:

Theresa M. Diehl
Research Geodesist
NOAA- National Geodetic Survey (N/NGS4)
1315 East-West Highway, SSMC3
Silver Spring, MD 20910
Phone: 301-713-3187 x136