HR: 0800h
AN: C21B-1100    [Abstracts]
TI: 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
AU: Horwath, M
EM: horwath@ipg.geo.tu-dresden.de
AF: Institut für Planetare Geodäsie, Technische Universität Dresden, Helmholtzstr. 10, Dresden, 01062 Germany
AU: Dietrich, R
EM: dietrich@ipg.geo.tu-dresden.de
AF: Institut für Planetare Geodäsie, Technische Universität Dresden, Helmholtzstr. 10, Dresden, 01062 Germany
AU: * Baessler, M
EM: baessler@ipg.geo.tu-dresden.de
AF: Institut für Planetare Geodäsie, Technische Universität Dresden, Helmholtzstr. 10, Dresden, 01062 Germany
AU: Nixdorf, U
EM: unixdorf@awi-bremerhaven.de
AF: Alfred Wegener Institute for Polar and Marine Research, P.O. Box 120161, Bremerhaven, 27515 Germany
AU: Steinhage, D
EM: dsteinhage@awi-bremerhaven.de
AF: Alfred Wegener Institute for Polar and Marine Research, P.O. Box 120161, Bremerhaven, 27515 Germany
AU: Fritzsche, D
EM: dfritsch@awi-potsdam.de
AF: Alfred Wegener Institute for Polar and Marine Research, P.O. Box 600149, Potsdam, 14473 Germany
AU: Damm, V
EM: volkmar.damm@bgr.de
AF: Federal Institute for Geosciences and Natural Resources, P.O. Box 510153, Hannover, 30631 Germany
AU: Reitmayr, G
EM: reitmayr@bgr.de
AF: Federal Institute for Geosciences and Natural Resources, P.O. Box 510153, Hannover, 30631 Germany
AB: 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-penetrating radar), 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). 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 area to an accumulation area. We compute mass flux and mass balance parameters. The combined effect of bottom mass balance and temporal change averaged over an essential part of Nivlisen is -654± 170 kg m^-2a^-1 which suggests bottom melting processes to dominate. We discuss our results, in particular in view of temporal ice mass changes and basal processes.
DE: 0728 Ice shelves
DE: 0730 Ice streams
DE: 0758 Remote sensing
DE: 0762 Mass balance (1218, 1223)
DE: 0776 Glaciology (1621, 1827, 1863)
SC: Cryosphere [C]
MN: Fall Meeting 2005