Global Positioning System Measurements of Crustal Motion in Antarctica

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9909467RaymondThis award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, provides funds for continuation of an effort, in collaboration with NASA, to develop autonomous, continuously operating Global Positioning System (GPS) stations in Antarctica. The objectives of the project for the coming year are to maintain operations at the two existing autonomous GPS stations, carry out further development work on the power and electronics systems for the stations, and analyze and publish existing data. The purpose of the Transantarctic Mountains (TAM) continuous GPS array is to measure vertical and horizontal displacement components resulting from glacial isostasy, viscoelastic, and elastic response to recent ice mass changes, and tectonic forces. The array will provide critical independent constraints on post-glacial rebound models, which in turn will improve the estimate of present-day ice mass balance from future satellite missions. These include the Gravity Recovery and Atmospheric Change Experiment (GRACE) dual satellite-to-satellite tracking gravity mission, and repeated measurements of the topography of the ice sheet to be made using the Geoscience Laser Altimeter System (GLAS) by the Ice, Cloud and land Elevation Satellite (ICESat) mission. During the next year, we propose to: (1) maintain operations at these two stations, by performing necessary repairs and maintenance; (2) perform maintenance at the wind generator test site at the McMurdo Transmitter Site; (3) perform static and dynamic finite element analysis (FEA) of a vertical axis wind turbine (same as is currently deployed at Mt Coates), and incorporate it into a system test-bed for end-to-end system testing at ambient and liquid nitrogen temperatures. The FEA will reveal the expected failure modes of the turbine to allow us to better understand the suitability of the unit to the harsh conditions expected, and also guide design modifications that may improve the design for the extreme conditions (winds in excess of 150 mph [66 m/s]). Finally, we will perform further in-depth data analysis to evaluate the results of our two sites and other permanent GPS sites in terms of existing predictions of post-glacial rebound induced deformation of the Antarctic plate.