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| Titel |
Seasonal changes of ice surface characteristics and productivity in the ablation zone of the Greenland Ice Sheet |
| VerfasserIn |
D. M. Chandler, J. D. Alcock, J. L. Wadham, S. L. Mackie, J. Telling |
| 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 ; 9, no. 2 ; Nr. 9, no. 2 (2015-03-06), S.487-504 |
| Datensatznummer |
250116765
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| Publikation (Nr.) |
 copernicus.org/tc-9-487-2015.pdf |
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| Zusammenfassung |
| Field and remote sensing observations in the ablation zone of the Greenland
Ice Sheet have revealed a diverse range of ice surface characteristics,
primarily reflecting the variable distribution of fine debris (cryoconite).
This debris reduces the surface albedo and is therefore an important control
on melt rates and ice sheet mass balance. Meanwhile, studies of ice sheet
surface biological processes have found active microbial communities
associated with the cryoconite debris, which may themselves modify the
cryoconite distribution. Due to the considerable difficulties involved with
collecting ground-based observations of the ice surface, our knowledge of
the physical and biological surface processes, and their links, remains very
limited. Here we present data collected at a field camp established in the
ice sheet ablation zone at 67° N, occupied for almost the entire
melt season (26 May–10 August 2012), with the aim of gaining a much more
detailed understanding of the physical and biological processes occurring on
the ice surface. These data sets include quadrat surveys of surface type,
measurements of ice surface ablation, and in situ biological oxygen demand
incubations to quantify microbial activity. In addition, albedo at the site
was retrieved from AVHRR (Advanced Very High Resolution Radiometer) remote sensing data. Observations of the areal
coverage of different surface types revealed a rapid change from complete
snow cover to the "summer" (summer study period) ice surface of patchy debris ("dirty ice") and
cryoconite holes. There was significant correlation between surface albedo,
cryoconite hole coverage and surface productivity during the melt season,
but microbial activity in "dirty ice" was not correlated with albedo and
varied widely throughout the season. While this link suggests the potential
for a remote-sensing approach to monitoring cryoconite hole biological
processes, very wide seasonal and spatial variability in net surface
productivity demonstrates the need for caution when extrapolating point
measurements of biological processes to larger temporal or spatial scales. |
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