Basal friction of Ice Stream E, West Antarctica

• Published in: Journal of Glaciology
• Main Authors: MacAyeal, Douglas R., Bindschadler, Robert A., Scambos, Theodore A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1995
• Subjects: Earth-Surface Processes; Antarc*; Antarctic; Antarctica; Ice Stream E; Journal of Glaciology; West Antarctica
• Online Access: http://dx.doi.org/10.1017/s0022143000016154; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000016154

Abstract We use surface velocity derived from sequential Landsat imagery and a control method to estimate the basal-friction distribution of a major West Antarctic ice stream. The area-averaged basal stress is approximately 1.4 × 10 4 Pa, or about 29% of the area-averaged driving stress of 4.9 × 10 4 Pa. Uncertainty of the derived area-averaged basal stress is difficult to assess and depends primarily on spatial variation of the flow-law rate factor in the constitutive law. Spatial variation associated with depth-averaged temperature variation gives an uncertainty of approximately ±10 3 Pa. Approximately 60% of the ice stream has a basal-stress magnitude less than 10 4 Pa, and approximately 30% has less than 10 3 Pa. These characteristics suggest the presence of a mechanically weak, water-charged subglacial till. Small-scale sticky spots where basal friction exceeds the area-averaged driving stress are scattered irregularly across the subglacial regime and comprise approximately 15% of the ice-stream area. Sticky spots cluster in regions where Landsat imagery suggests structural features in the underlying bedrock.