Articles | Volume 4, issue 4
The Cryosphere, 4, 467–474, 2010
The Cryosphere, 4, 467–474, 2010

Research article 02 Nov 2010

Research article | 02 Nov 2010

Spatially extensive estimates of annual accumulation in the dry snow zone of the Greenland Ice Sheet determined from radar altimetry

S. de la Peña1, P. Nienow1, A. Shepherd2, V. Helm3, D. Mair4, E. Hanna5, P. Huybrechts6, Q. Guo7, R. Cullen8, and D. Wingham9 S. de la Peña et al.
  • 1School of Geosciences, University of Edinburgh, Drummond St. EH8 9XP, UK
  • 2School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
  • 3Alfred Wegener Institute, Am Handelshafen 12, 27570, Bremerhaven, Germany
  • 4Department of Geography and Environment, University of Aberdeen, Elphinstone Road, Aberdeen , AB24 3UF, UK
  • 5Department of Geography, University of Sheffield, Sheffield, S10 2TN, UK
  • 6Earth System Sciences, Department of Geography, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel, Belgium
  • 7School of Engineering, University of California Merced, 5200 North Lake Rd., Merced, CA 95343, USA
  • 8European Space Agency ESTEC, Keplerlaan 1, Postbus 299, 2200 AG Noordwijk, The Netherlands
  • 9Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK

Abstract. We present estimates of accumulation rate along a 200 km transect ranging in elevation from 2750 to 3150 m in the dry snow zone on the western slope of the Greenland Ice Sheet. An airborne radar altimeter is used to estimate the thickness of annual internal layers and, in conjunction with ground based snow/firn density profiles, annual accumulation rates between 1998 and 2003 are derived. A clear gradient in the thickness of each layer observed by the radar altimeter and in the associated estimates of annual accumulation is seen along the transect, with a 33.6% ± 16% mean decrease in accumulation from west to east. The observed inter-annual variability is high, with the annual mean accumulation rate estimated at 0.359 m.w.e. yr−1 (s.d. ± 0.049 m.w.e. yr−1). Mean accumulation rates modelled using meteorological models overestimate our results by 16% on average, but by 32% and 42% in the years 2001 and 2002. The methodology presented here demonstrates the potential to obtain accurate and spatially extensive accumulation rates from radar altimeters in regions of ice sheets where field observations are sparse, and accumulation rates greater than several tens of cm.