HR: 0800h
AN: C51A-0101    [Abstracts]
TI: A Comparison of Two Models That Predict the Tidal Influence on the Flow of the Ross Ice Shelf, Antarctica
AU: * Brunt, K M
EM: kbrunt@uchicago.edu
AF: University of Chicago, 5734 S. Ellis Ave, Department of Geophysics, Chicago, IL 60615, United States
AU: MacAyeal, D R
EM: drm7@midway.uchicago.edu
AF: University of Chicago, 5734 S. Ellis Ave, Department of Geophysics, Chicago, IL 60615, United States
AB: Three stations near the calving front of the Ross Ice Shelf, Antarctica, recorded GPS data through a full spring-to- neap tidal cycle in 2005 and yielded a tantalizing diurnal signal, similar to those observed in other ice shelves [Doake et al., 2002] and ice streams [Anandakrishnan et al., 2003 and Bindschadler et al., 2003 a and b]. Based on the steady timing of the signal, it was hypothesized that the signal was related to the tides, which are strongly diurnal in the Ross Sea. To assess the influence of the tide on the ice-shelf motion, two model experiments using ocean tidal fields provided by Padman et al. [2002] were conducted and the results were compared. The first, more general model approach satisfies the full non-linearity of the governing stress-balance equations using numerical techniques. The solution obtained suggests that the tidal influence is small (less than 10 percent of the mean) compared to the time-averaged flow of the ice shelf. The small size of this response suggests that a linearization of the problem may be a fruitful and a much simpler approach to the problem. Thus, the second model approach uses a linearization of the governing stress balance equations and provides a check on the initial approach. The main non-linearity in the governing equations is associated with the vertically averaged effective viscosity. To linearize the equations, viscosity is associated with that computed for an ice shelf in the absence of tidal forcing.
DE: 0550 Model verification and validation
DE: 0700 CRYOSPHERE (4540)
DE: 0728 Ice shelves
DE: 0730 Ice streams
DE: 0798 Modeling
SC: Cryosphere [C]
MN: 2007 Fall Meeting