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| Titel |
Simulating the growth of supraglacial lakes at the western margin of the Greenland ice sheet |
| VerfasserIn |
A. A. Leeson, A. Shepherd, S. Palmer, A. Sundal, X. Fettweis |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 6, no. 5 ; Nr. 6, no. 5 (2012-10-02), S.1077-1086 |
| Datensatznummer |
250003788
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| Publikation (Nr.) |
 copernicus.org/tc-6-1077-2012.pdf |
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| Zusammenfassung |
| We present a new method of modelling the growth of supraglacial lakes at the
western margin of the Greenland ice sheet, based on routing runoff estimated
by a regional climate model across a digital elevation model (DEM) of the
ice sheet surface. Using data acquired during the 2003 melt season, we
demonstrate that the model is 19 times more likely to correctly predict the
presence (or absence) of lakes than it is to make incorrect predictions,
within an elevation range of 1100 to 1700 metres above sea level (m a.s.l.),
when compared with MODIS satellite imagery. Of the 66% of observed lake
locations which the model correctly reproduces, the simulated lake onset day is
found to be correlated with that observed with a Pearson correlation
coefficient of 0.76. Our model accurately simulates maximum cumulative lake
area with only a 1.5% overestimate. However, because our model does not
simulate processes leading to lake stagnation or decay, such as refreezing
or drainage, at present we do not simulate absolute daily lake area. We find
that the maximum potential lake-covered ice sheet area is limited by
topography to 6.4%. We estimate that this corresponds to a volume of
1.49 km3, 12% of the runoff produced in 2003. This can be taken as
an upper bound given uncertainty in the DEM. This study has proved a good
first step towards capturing the variability of supraglacial lake evolution
with a numerical model. These initial results are promising and suggest that
the model is a useful tool for use in analysing the behaviour of
supraglacial lakes on the Greenland ice sheet in the present day and
potentially beyond. |
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