Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Published Online May 29, 2008
Science DOI: 10.1126/science.1153894

Reports

Submitted on December 7, 2007
Accepted on May 7, 2008

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 Goodwin 4

1 Institute for Marine and Atmospheric Research, Utrecht University, Utrecht, Netherlands.
2 Royal Netherlands Meteorological Institute, 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, Australia.; Present address: Climate Risk CoRE and Department of Physical Geography, Macquarie University, NSW 2109, Australia.

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

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. Here we quantify the effects of temperature and accumulation variability on firn layer thickness, by simulating the 1980–2004 Antarctic firn depth variability. We demonstrate that, for most of Antarctica, firn depth changes are of comparable magnitude as 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) is increased by including firn depth fluctuations, while a large area of the East Antarctic ice sheet slowly grew due to increased accumulation.




To Advertise     Find Products

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