Abstract
ICESat has provided surface elevation measurements of the ice sheets
since the launch in January 2003, resulting in a unique data set 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. Four different methods for deriving
the elevation changes from the ICESat altimetry data set are used. This
multi method approach gives an understanding of the complexity
associated with deriving elevation changes from the ICESat altimetry
data set. The altimetry can not stand alone in estimating
the mass balance of the Greenland ice sheet. We find firn dynamics and
surface densities to be important factors in deriving the mass loss from
remote sensing altimetry. The volume change derived from ICESat data is
corrected for firn compaction, vertical bedrock movement and an
intercampaign elevation bias in the ICESat data. Subsequently, the
corrected volume change is converted into mass change by surface density
modelling. The firn compaction and density models are driven by a
dynamically downscaled simulation of the HIRHAM5 regional climate model
using ERA-Interim reanalysis lateral boundary conditions.
We find an annual mass loss of the Greenland ice sheet of 210 ±
21 Gt yr-1 in the period from October 2003 to March
2008. This result is in good agreement with other studies of the
Greenland ice sheet mass balance, based on different remote sensing
techniques.
Original language | English |
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Journal | The Cryosphere Discussions |
Volume | 4 |
Issue number | 4 |
Pages (from-to) | 2103-2141 |
ISSN | 1994-0432 |
DOIs | |
Publication status | Published - 1 Oct 2010 |