Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
The Cryosphere, 9, 805-819, 2015
http://www.the-cryosphere.net/9/805/2015/
doi:10.5194/tc-9-805-2015
© Author(s) 2015. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
30 Apr 2015
Simultaneous solution for mass trends on the West Antarctic Ice Sheet
N. Schoen1, A. Zammit-Mangion1,2, J. C. Rougier2, T. Flament3, F. Rémy3, S. Luthcke4, and J. L. Bamber1 1Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, UK
2Department of Mathematics, University of Bristol, UK
3LEGOS, Toulouse, France
4NASA, Greenbelt, MD, USA
Abstract. The Antarctic Ice Sheet is the largest potential source of future sea-level rise. Mass loss has been increasing over the last 2 decades for the West Antarctic Ice Sheet (WAIS) but with significant discrepancies between estimates, especially for the Antarctic Peninsula. Most of these estimates utilise geophysical models to explicitly correct the observations for (unobserved) processes. Systematic errors in these models introduce biases in the results which are difficult to quantify. In this study, we provide a statistically rigorous error-bounded trend estimate of ice mass loss over the WAIS from 2003 to 2009 which is almost entirely data driven. Using altimetry, gravimetry, and GPS data in a hierarchical Bayesian framework, we derive spatial fields for ice mass change, surface mass balance, and glacial isostatic adjustment (GIA) without relying explicitly on forward models. The approach we use separates mass and height change contributions from different processes, reproducing spatial features found in, for example, regional climate and GIA forward models, and provides an independent estimate which can be used to validate and test the models. In addition, spatial error estimates are derived for each field. The mass loss estimates we obtain are smaller than some recent results, with a time-averaged mean rate of −76 ± 15 Gt yr−1 for the WAIS and Antarctic Peninsula, including the major Antarctic islands. The GIA estimate compares well with results obtained from recent forward models (IJ05-R2) and inverse methods (AGE-1). The Bayesian framework is sufficiently flexible that it can, eventually, be used for the whole of Antarctica, be adapted for other ice sheets and utilise data from other sources such as ice cores, accumulation radar data, and other measurements that contain information about any of the processes that are solved for.

Citation: Schoen, N., Zammit-Mangion, A., Rougier, J. C., Flament, T., Rémy, F., Luthcke, S., and Bamber, J. L.: Simultaneous solution for mass trends on the West Antarctic Ice Sheet, The Cryosphere, 9, 805-819, doi:10.5194/tc-9-805-2015, 2015.
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Short summary
This paper provides a proof of concept approach for combining multiple observations and inferences to provide rigorous, error-bounded estimates of mass trends and surface processes for the Antarctic ice sheet. Here we apply the method to West Antarctica, using a time-invariant solution by way of proof of concept. Subsequent work will utilise a time evolving approach to the whole ice sheet.
This paper provides a proof of concept approach for combining multiple observations and...
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