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Originally published in Science Express on 29 May 2008
Science 20 June 2008:
Vol. 320. no. 5883, pp. 1626 - 1629
DOI: 10.1126/science.1153894
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Reports

Elevation Changes in Antarctica Mainly Determined by Accumulation Variability

Michiel M. Helsen,1* Michiel R. van den Broeke,1 Roderik S. W. van de Wal,1 Willem Jan van de Berg,1 Erik van Meijgaard,2 Curt H. Davis,3 Yonghong Li,3 Ian Goodwin4{dagger}

Antarctic Ice Sheet elevation changes, which are used to estimate changes in the mass of the interior regions, are caused by variations in the depth of the firn layer. We quantified the effects of temperature and accumulation variability on firn layer thickness by simulating the 1980–2004 Antarctic firn depth variability. For most of Antarctica, the magnitudes of firn depth changes were comparable to those of observed ice sheet elevation changes. The current satellite observational period (~15 years) is too short to neglect these fluctuations in firn depth when computing recent ice sheet mass changes. The amount of surface lowering in the Amundsen Sea Embayment revealed by satellite radar altimetry (1995–2003) was increased by including firn depth fluctuations, while a large area of the East Antarctic Ice Sheet slowly grew as a result of increased accumulation.

1 Institute for Marine and Atmospheric Research, Utrecht University, 3584 CC Utrecht, Netherlands.
2 Royal Netherlands Meteorological Institute, 3732 GK De Bilt, Netherlands.
3 Department of Electrical and Computer Engineering, University of Missouri, Columbia, MO 65211, USA.
4 School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia.

{dagger} Present address: Climate Risk CoRE and Department of Physical Geography, Macquarie University, NSW 2109, Australia.

* To whom correspondence should be addressed. E-mail: m.m.helsen{at}uu.nl

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Science. ISSN 0036-8075 (print), 1095-9203 (online)