Preliminary Determination of Ice Flow Velocity in West Antarctica Using High Precision GPS Measurements

Xin Chen, Robert A. Bindschadler and Patricia L. Vornberger

Abstract:	In order to study the ice dynamics of ice stream D in West Antarctica, a grid of 385 GPS survey points has been established in a 160 km x 60 km area at a nominal spacing of 5 km. The first survey was car- ried out in December 1995. The grid was divided into 11 blocks, each having a central local base sta- tion collecting static GPS data for typically two days, while other points were measured in either rapid-static or stopand-go mode. In addition, a continuous run- ning base station at Byrd station collected data for 26 days. A second survey is planned for November 1996. Although most objectives of this project can only be achieved after the second survey, we have obtained ac- curate velocity estimates for those base stations by taking advantage of the continuously collected static data, and obtained approximate velocity estimates for the block boundary points which were occupied more than once with respect to different local bsse stations. The GPS data are post-processed using GIPSY soft- ware and JPL precise orbital products. The magni- tude of these velocity estimates is in a range from 11 m/a to 84 m/a, with errors of 0.1 m/a for Byrd sta- tion, a few m/a for the local base stations, and up to a few tens of m/a for the boundary points. For the base stations, the RMS errors from the linear fit of the solutions, which in general represent the precisions of the GPS solutions, are at centimeter or sub-centimeter level in the horizontal and the few centimeter level in the vertical. For other points, the RMS errors are at a few centimeter level in the horizontal. Glaciological aspects of the survey area, data acquisition, and data processing strategy are also presented in this paper.
Published in:	Proceedings of the 9th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1996) September 17 - 20, 1996 Kansas City, MO
Pages:	1853 - 1861
Cite this article:	Chen, Xin, Bindschadler, Robert A., Vornberger, Patricia L., "Preliminary Determination of Ice Flow Velocity in West Antarctica Using High Precision GPS Measurements," Proceedings of the 9th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1996), Kansas City, MO, September 1996, pp. 1853-1861.
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