The Nivlisen, an Antarctic ice shelf in Dronning Maud Land: geodetic-glaciological results from a combined analysis of ice thickness, ice surface height and ice flow observations

• Main Authors: Horwath, M., Dietrich, R., Baessler, M., Nixdorf, Uwe, Steinhage, Daniel, Fritzsche, Diedrich, Damm, V., Reitmayr, G.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2006
• Subjects: Antarctic; Dronning Maud Land; Nivlisen; Antarc*; Ice Shelf; Journal of Glaciology
• Online Access: https://epic.awi.de/id/eprint/10564/; https://epic.awi.de/id/eprint/10564/1/Wie2005a.pdf; https://hdl.handle.net/10013/epic.21041; https://hdl.handle.net/10013/epic.21041.d001

Extensive observations on Nivlisen, an ice shelf at Antarctica's Atlantic coast, are analysed and combined to achieve a new-quality description of its complex glaciological regime. We generate models of ice thickness (primarily from ground-penetratingradar), ellipsoidal ice surface height (primarily from ERS-1 satellite altimetry), freeboard height (by utilising precise sea surface information), and ice flow velocity(from ERS-1/2 SAR interferometry and GPS measurements). Accuracy assessmentsare included. Exploiting the hydrostatic equilibrium relation we infer the 'apparent air layer thickness' as a useful measure for a glacier's density deviation from a pure ice body. This parameter exhibits a distinct spatial variation (ranging from 2 m to 16 m) which we attribute to the transition from an ablation areato an accumulation area. We compute mass flux and mass balance parameters on a local and areally integrated scale. The combined effect of bottom mass balance and temporal change averaged over an essential part of Nivlisen is -654±170 kgm2a-1 which suggests bottom melting processes to dominate. We discuss our results in view of temporal ice mass changes (including remarks on historical observations),basal processes, near-surface processes, and ice-flow dynamical features. The questionfor temporal changes remains open from the data at hand, and we recommendfurther observations and analyses for its solution.