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| Titel |
The seasonal cycle and interannual variability of surface energy balance and melt in the ablation zone of the west Greenland ice sheet |
| VerfasserIn |
M. R. Broeke, C. J. P. P. Smeets, R. S. W. Wal |
| 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 ; 5, no. 2 ; Nr. 5, no. 2 (2011-05-16), S.377-390 |
| Datensatznummer |
250002430
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| Publikation (Nr.) |
 copernicus.org/tc-5-377-2011.pdf |
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| Zusammenfassung |
| We present the seasonal cycle and interannual variability of the surface
energy balance (SEB) in the ablation zone of the west Greenland ice sheet,
using seven years (September 2003–August 2010) of hourly observations from
three automatic weather stations (AWS). The AWS are situated along the 67° N
latitude circle at elevations of 490 m a.s.l. (S5), 1020 m a.s.l. (S6) and 1520 m a.s.l. (S9)
at distances of 6, 38 and 88 km from the ice sheet margin. The
hourly AWS data are fed into a model that calculates all SEB components and
melt rate; the model allows for shortwave radiation penetration in ice and
time-varying surface momentum roughness. Snow depth is prescribed from
albedo and sonic height ranger observations. Modelled and observed surface
temperatures for non-melting conditions agree very well, with RMSE's of
0.97–1.26 K. Modelled and observed ice melt rates at the two lowest sites
also show very good agreement, both for total cumulative and 10-day
cumulated amounts. Melt frequencies and melt rates at the AWS sites are
discussed. Although absorbed shortwave radiation is the most important
energy source for melt at all three sites, interannual melt variability at
the lowest site is driven mainly by variability in the turbulent flux of
sensible heat. This is explained by the quasi-constant summer albedo in the
lower ablation zone, limiting the influence of the melt-albedo feedback, and
the proximity of the snow free tundra, which heats up considerably in
summer. |
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