Mass balance of the Greenland ice sheet (2003–2008) from ICESat data – the impact of interpolation, sampling and firn density 1Geodynamics Department, DTU Space, Juliane Maries vej 30, 2100 Copenhagen, Denmark
09 Mar 2011
2Planet and Geophysics, NBI, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen, Denmark
3Centre for Ice and Climate, NBI, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen, Denmark
4Danish Climate Centre, DMI, Lyngbyvej 100, 2100 Copenhagen, Denmark
5Geodesy Department, DTU Space, Juliane Maries vej 30, 2100 Copenhagen, Denmark
6Dipartimento di Scienze di Base e Fondamenti, Urbino University "Carlo Bo", Via Santa Chiara, 27, 61029 Urbino (PU), Italy
*These authors contributed equally to this work.
Received: 20 September 2010 – Published in The Cryosphere Discuss.: 15 October 2010 Abstract. ICESat has provided surface elevation measurements of the ice sheets
since the launch in January 2003, resulting in a unique dataset for
monitoring the changes of the cryosphere. Here, we present a novel
method for determining the mass balance of the Greenland ice sheet,
derived from ICESat altimetry data.
Revised: 01 February 2011 – Accepted: 10 February 2011 – Published: 09 March 2011
Three different methods for deriving elevation changes from the
ICESat altimetry dataset are used. This multi-method approach provides
a method to assess the complexity of deriving elevation
changes from this dataset.
The altimetry alone can not provide an estimate of the mass balance of the
Greenland ice sheet. Firn dynamics and surface densities are important
factors that contribute to the mass change derived from remote-sensing
altimetry. The volume change derived from ICESat data is corrected for
changes in firn compaction over the observation period, vertical bedrock
movement and an intercampaign elevation bias in the ICESat data.
Subsequently, the corrected volume change is converted into mass change by
the application of a simple surface density model, in which some of the ice
dynamics are accounted for. The firn compaction and density models are driven
by the HIRHAM5 regional climate model, forced by the ERA-Interim re-analysis
product, at the lateral boundaries.
We find annual mass loss estimates of the Greenland ice sheet in the range of
191 ± 23 Gt yr−1 to 240 ± 28 Gt yr−1 for the period
October 2003 to March 2008. These results are in good agreement with
several other studies of the Greenland ice sheet mass balance, based on
different remote-sensing techniques.
Citation: Sørensen, L. S., Simonsen, S. B., Nielsen, K., Lucas-Picher, P., Spada, G., Adalgeirsdottir, G., Forsberg, R., and Hvidberg, C. S.: Mass balance of the Greenland ice sheet (2003–2008) from ICESat data – the impact of interpolation, sampling and firn density, The Cryosphere, 5, 173-186, doi:10.5194/tc-5-173-2011, 2011.