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Titel |
Air temperature variability over three glaciers in the Ortles–Cevedale (Italian Alps): effects of glacier fragmentation, comparison of calculation methods, and impacts on mass balance modeling |
VerfasserIn |
L. Carturan, F. Cazorzi, F. Blasi, G. Dalla Fontana |
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. 3 ; Nr. 9, no. 3 (2015-05-27), S.1129-1146 |
Datensatznummer |
250116805
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Publikation (Nr.) |
copernicus.org/tc-9-1129-2015.pdf |
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Zusammenfassung |
Glacier mass balance models rely on accurate spatial calculation of input
data, in particular air temperature. Lower temperatures (the so-called
glacier cooling effect) and lower temperature variability (the so-called
glacier damping effect) generally occur over glaciers compared to ambient
conditions. These effects, which depend on the geometric characteristics of
glaciers and display a high spatial and temporal variability, have been
mostly investigated on medium to large glaciers so far, while
observations on smaller ice bodies (< 0.5 km2) are scarce. Using
a data set from eight on-glacier and four off-glacier weather stations,
collected in the summers of 2010 and 2011, we analyzed the air temperature
variability and wind regime over three different glaciers in the
Ortles–Cevedale. The magnitude of the cooling effect and the occurrence of
katabatic boundary layer (KBL) processes showed remarkable differences among
the three ice bodies, suggesting the likely existence of important
reinforcing mechanisms during glacier decay and fragmentation. The methods
proposed by Greuell and Böhm (1998) and Shea and Moore (2010) for
calculating on-glacier temperature from off-glacier data did not fully
reproduce our observations. Among them, the more physically based procedure
of Greuell and Böhm (1998) provided the best overall results where the
KBL prevails, but it was not effective elsewhere (i.e., on smaller ice bodies
and close to the glacier margins). The accuracy of air temperature
estimations strongly impacted the results from a mass balance model which was
applied to the three investigated glaciers. Most importantly, even small
temperature deviations caused distortions in parameter calibration, thus
compromising the model generalizability. |
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