Annals rifGlaciology 24 1997 © International Glaciological Society Large-scale rheology of the Ross Ice Shelf, Antarctica, computed by a control method

• Main Author: Vincent R Ommelaere
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Ross Ice Shelf; Antarc*; Antarctica; Ice Shelf; Ice Stream A
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.466.5805; http://www.igsoc.org:8080/annals/24/igs_annals_vol24_year1997_pg43-48.pdf

logical Survey (RIGGS, 1973-78) are used to determine the large-scale rheological condi-tions of the Ross Ice Shelf, Antarctica. Our method includes a numerical ice-shelf model based on the stress-equi librium equations and control theory. We additionally perform a few tests on simplified geometries to investigate the precision of our method. Our resu lts consist of a map of the depth-averaged viscosity of the central part of the Ross Ice Shelf to within an uncertainty of 20%. We find that the viscosity variations are consistent with Glen's flow law. Application of a more realistic flow law in our study provides little en-hancement of ice-shelf model accuracy until uncertainties associated with basal melting conditions and with temperature proG les at inflow boundaries are addressed. Finally, our results suggest a strong viscosit y anomaly in the west-central part of the ice shelf, which is interpreted to be associated with changes in the dynamics of Ice Stream A or B at least 1000 years ago. This feature conforms to the prevai ling notion that the West Antarctic ice streams are unsteady.