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| Titel |
Snow accumulation and compaction derived from GPR data near Ross Island, Antarctica |
| VerfasserIn |
N. C. Kruetzmann, W. Rack, A. J. McDonald, S. E. George |
| 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 (2011-05-18), S.391-404 |
| Datensatznummer |
250002431
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| Publikation (Nr.) |
 copernicus.org/tc-5-391-2011.pdf |
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| Zusammenfassung |
| We present an improved method for estimating accumulation and compaction
rates of dry snow in Antarctica with ground penetrating radar (GPR). Using
an estimate of the emitted waveform from direct measurements, we apply
deterministic deconvolution via the Fourier domain to GPR data with a
nominal frequency of 500 MHz. This reveals unambiguous reflection horizons
which can be observed in repeat measurements made one year apart. At two
measurement sites near Scott Base, Antarctica, we extrapolate point
measurements of average accumulation from snow pits and firn cores to a
larger area by identifying a dateable dust layer horizon in the radargrams.
Over an 800 m × 800 m area on the McMurdo Ice Shelf (77°45´ S,
167°17´ E) the average accumulation is found to be 269 ± 9 kg m−2 a−1.
The accumulation over an area of 400 m × 400 m on Ross Island
(77°40´ S, 167°11´ E, 350 m a.s.l.) is found to be higher (404 ± 22 kg m−2 a−1) and shows increased variability related to
undulating terrain. Compaction of snow between 2 m and 13 m depth is
estimated at both sites by tracking several internal reflection horizons
along the radar profiles and calculating the average change in separation of
horizon pairs from one year to the next. The derived compaction rates range
from 7 cm m−1 at a depth of 2 m, down to no measurable
compaction at 13 m depth, and are similar to published values from
point measurements. |
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