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| Titel |
Specific surface area of snow at Dome C, Antarctica. Rates of change for timescales from 1 day to 60 years |
| VerfasserIn |
J.-C. Gallet, L. Arnaud, F. Domine |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250022755
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| Zusammenfassung |
| The specific surface area (SSA) is a central variable to characterize porous media
such as snow. Moreover, snow SSA is required to understand the chemical and
climatic impact of the snow cover. At present, almost no data is available on the
SSA of snow of the largest snow expanse on Earth: the Antarctic ice cap. We have
measured the SSA of snow at Dome C, Antarctica (75˚ S, 123˚ E, 3250 m elevation)
using infrared reflectance at 1310 nm and an integrating sphere. The method has an
accuracy of 10%. Several hundred measurements were made to study its spatial
and temporal variations. Surface values reach 53 m2 kg-1 and show some slight
diurnal variations explained by the formation of surface hoar at “night” and its
sublimation in the “day”. SSA vertical profiles down to 5 m were performed, and the
lowest value observed is 7.8 m2 kg-1. Given the low accumulation rates at Dome C,
these latter data allow the test of SSA rate laws for regimes where the curvature
distribution of snow crystals can be expected to be at steady state. In particular, the
applicability of Ostwald ripening theories is tested for snows that are up to 60 years old. |
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