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| Titel |
Event-driven deposition of snow on the Antarctic Plateau: analyzing field measurements with SNOWPACK |
| VerfasserIn |
C. D. Groot Zwaaftink, A. Cagnati, A. Crepaz, C. Fierz, G. Macelloni, M. Valt, M. Lehning |
| 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 ; 7, no. 1 ; Nr. 7, no. 1 (2013-02-27), S.333-347 |
| Datensatznummer |
250017934
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| Publikation (Nr.) |
 copernicus.org/tc-7-333-2013.pdf |
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| Zusammenfassung |
| Antarctic surface snow has been studied by means of continuous measurements
and observations over a period of 3 yr at Dome C. Snow observations
include solid deposits in form of precipitation, diamond dust, or hoar, snow
temperatures at several depths, records of deposition and erosion on the
surface, and snow profiles. Together with meteorological data from automatic
weather stations, this forms a unique dataset of snow conditions on the
Antarctic Plateau. Large differences in snow amounts and density exist
between solid deposits measured 1 m above the surface and deposition at the
surface. We used the snow-cover model SNOWPACK to simulate the snow-cover
evolution for different deposition parameterizations. The main adaptation of
the model described here is a new event-driven deposition scheme. The scheme
assumes that snow is added to the snow cover permanently only during periods
of strong winds. This assumption followed from the comparison between
observations of solid deposits and daily records of changes in snow height:
solid deposits could be observed on tables 1 m above the surface on 94 out
of 235 days (40%) while deposition at the surface occurred on 59 days
(25%) during the same period, but both happened concurrently on 33 days
(14%) only. This confirms that precipitation is not necessarily the
driving force behind non-temporary snow height changes. A comparison of
simulated snow height to stake farm measurements over 3 yr showed that we
underestimate the total accumulation by at least 33%, when the total
snow deposition is constrained by the measurements of solid deposits on
tables 1 m above the surface. During shorter time periods, however, we may
miss over 50% of the deposited mass. This suggests that the solid
deposits measured above the surface and used to drive the model, even though
comparable to ECMWF forecasts in its total magnitude, should be seen as a
lower boundary. As a result of the new deposition mechanism, we found a good
agreement between model results and measurements of snow temperatures and
recorded snow profiles. In spite of the underestimated deposition, the
results thus suggest that we can obtain quite realistic simulations of the
Antarctic snow cover by the introduction of event-driven snow deposition. |
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