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. 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.
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Cryosphere |
| Vol/bind | 5 |
| Udgave nummer | 1 |
| Sider (fra-til) | 173-186 |
| ISSN | 1994-0416 |
| Status | Udgivet - 1 mar. 2011 |
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