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


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dfritsch [ at ] awi-potsdam.de

Abstract

<jats:title>Abstract</jats:title><jats:p>Extensive observations on Nivlisen, an ice shelf on Antarctica’s Atlantic coast, are analyzed and combined to obtain a new 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 utilizing precise sea surface information) and ice-flow velocity (from ERS-1/-2 SAR interferometry and GPS measurements). Accuracy assessments are 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 to ≈16m) which we attribute to the transition from an ablation area to 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 kg m<jats:sup>–2</jats:sup> a<jats:sup>–1</jats:sup>, which suggests bottom melting processes 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 question of temporal changes remains open from the data at hand, and we recommend further observations and analyses for its solution.</jats:p>



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ISI/Scopus peer-reviewed
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Eprint ID
10564
DOI https://www.doi.org/10.3189/172756506781828953

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Horwath, M. , Dietrich, R. , Baessler, M. , Nixdorf, U. , Steinhage, D. , Fritzsche, D. , Damm, V. and Reitmayr, G. (2006): 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 , Journal of Glaciology, 52 (176), pp. 17-30 . doi: https://www.doi.org/10.3189/172756506781828953


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