Abstract
Abstract. Digital elevation models of Antarctic bed topography are smoothed and interpolated onto low-resolution ( > 1 km) grids as current observed topography data are generally sparsely and unevenly sampled. This issue has potential implications for numerical simulations of ice-sheet dynamics, especially in regions prone to instability where detailed knowledge of the topography, including fine-scale roughness, is required. Here, we present a high-resolution (100 m) synthetic bed elevation terrain for Antarctica, encompassing the continent, continental shelf, and seas south of 60° S. Although not identically matching observations, the synthetic bed surface – denoted as HRES – preserves topographic roughness characteristics of airborne and ground-based ice-penetrating radar data measured by the ICECAP (Investigating the Cryospheric Evolution of the Central Antarctic Plate) consortium or used to create the Bedmap1 compilation. Broad-scale ( > 5 km resolution) features of the Antarctic landscape are incorporated using a low-pass filter of the Bedmap2 bed elevation data. HRES has applicability in high-resolution ice-sheet modelling studies, including investigations of the interaction between topography, ice-sheet dynamics, and hydrology, where processes are highly sensitive to bed elevations and fine-scale roughness. The data are available for download from the Australian Antarctic Data Centre (doi:10.4225/15/57464ADE22F50).
Highlights
The largest source of uncertainty in projections of sea-level rise to the end of the 21st century is derived from poorly constrained estimates of mass loss from the Antarctic and Greenland ice sheets (Church et al, 2013)
Sentially identical; the difference between them (D = Bedmap2 − high-resolution synthetic bed topography dataset for Antarctica (HRES); Fig. 3c) is essentially a measure of the Cholesky decomposition roughness terrain (CDRT) roughness introduced in HRES
HRES was generated from a non-conditional simulation of the ICECAP/BC1 data that is unlikely to honour the exact values of the underlying data
Summary
The largest source of uncertainty in projections of sea-level rise to the end of the 21st century is derived from poorly constrained estimates of mass loss from the Antarctic and Greenland ice sheets (Church et al, 2013). Where an ice sheet rests on a bed topography that is below sea level and deepens towards the ice-sheet interior, marine ice-sheet instability (MISI) could occur, leading to increased ice flow, thinning, and rapid grounding line retreat (Weertman, 1974; Thomas et al, 2004; Schoof, 2007a; Durand et al, 2009; Goldberg et al, 2009; Favier et al, 2014; Joughin et al, 2014) It follows that bed elevation is one of the most important controls in modelling ice-sheet dynamics and constraining estimates of future sea-level rise.
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