HR: 14:40h
AN: C43A-05    [Abstracts]
TI: Tidal Modulation of the Flow of Rutford Ice Stream, West Antarctica
AU: * Adalgeirsdottir, G
EM: g.adalgeirsdottir@swan.ac.uk
AF: Department of Geography University of Wales Swansea, Singleton Park, Swansea, SA2 8PP United Kingdom
AU: Murray, T
EM: t.murray@swan.ac.uk
AF: Department of Geography University of Wales Swansea, Singleton Park, Swansea, SA2 8PP United Kingdom
AU: Smith, A
EM: amsm@bas.ac.uk
AF: Physical Sciences Division, British Antarctic Survey, Cambridge, CB3 0ET United Kingdom
AU: Nicholls, K
EM: kwni@bas.ac.uk
AF: Physical Sciences Division, British Antarctic Survey, Cambridge, CB3 0ET United Kingdom
AU: Makinson, K
EM: kmak@bas.ac.uk
AF: Physical Sciences Division, British Antarctic Survey, Cambridge, CB3 0ET United Kingdom
AU: King, M
EM: m.a.king@ncl.ac.uk
AF: School of Civil Engineering and Geosciences, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU United Kingdom
AU: Behar, A
EM: alberto.behar@jpl.nasa.gov
AF: Robotic Vehicles Group, NASA-JPL, Pasadena, CA 91109 United States
AB: Ice from the interior of Antarctica is delivered to the ice shelves and the oceans through fast flowing ice streams and glaciers. The ice streams flow up to two orders of magnitude faster than the surrounding ice and are the most dynamic components of the ice sheet system. As a part of the RABID project an array of 5 GPS receivers, was operated continuously on the Rutford Ice stream, West Antarctica, from 28 December 2004 - 3 February 2005, about 40 km upstream from the grounding line. The chosen sampling rate was 10 sec, which gives high resolution data on the ice stream motion. A base station was deployed on rock in the Ellsworth Mountains, ~30 km from the array, providing a fixed control for the ice stream network. The data are processed with rigorous kinematic methods. The measured velocity of the ice stream is about 1 m per day. After removing the mean velocity along the ice stream from the measurement the residual of the horizontal displacement shows periodicity of ~15 days, which is related to the spring-neap tides. The variation in velocity is about 5%. Highest velocity is measured during the transition from spring to neap tide, with the largest increase in speed during spring tide and decrease during neap tides. A weak diurnal signal is visible during spring tides. The amplitude of the diurnal signal decreases during neap tides.
DE: 0730 Ice streams
DE: 0774 Dynamics
SC: Cryosphere [C]
MN: Fall Meeting 2005