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| Titel |
Utility of late summer transient snowline migration rate on Taku Glacier, Alaska |
| VerfasserIn |
M. Pelto |
| 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. 4 ; Nr. 5, no. 4 (2011-12-15), S.1127-1133 |
| Datensatznummer |
250002763
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| Publikation (Nr.) |
 copernicus.org/tc-5-1127-2011.pdf |
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| Zusammenfassung |
| On Taku Glacier, Alaska a combination of field observations of snow water
equivalent (SWE) from snowpits and probing in the vicinity of the transient
snowline (TSL) are used to quantify the mass balance gradient. The balance
gradient derived from the TSL and SWE measured in snowpits at 1000 m from
1998–2010 ranges from 2.6–3.8 mm m−1. Probing transects from 950 m–1100 m directly measure SWE and yield a slightly higher balance gradient of
3.3–3.8 mm m−1. The TSL on Taku Glacier is identified in MODIS and
Landsat 4 and 7 Thematic Mapper images for 31 dates during the 2004–2010
period to assess the consistency of its rate of rise and reliability in
assessing ablation for mass balance assessment. For example, in 2010, the
TSL was 750 m on 28 July, 800 m on 5 August, 875 m on 14 August, 925 m on
30 August, and 975 m on 20 September. The mean observed probing balance
gradient was 3.3 mm m−1, combined with the TSL rise of 3.7 m day−1 yields
an ablation rate of 12.2 mm day−1 from mid-July to mid-Sept, 2010. The TSL
rise in the region from 750–1100 m on Taku Glacier during eleven periods
each covering more than 14 days during the ablation season indicates a mean
TSL rise of 3.7 m day−1, the rate of rise is relatively consistent ranging
from 3.1 to 4.4 m day−1. This rate is useful for ascertaining the final ELA if
images or observations are not available near the end of the ablation
season. The mean ablation from 750–1100 m during the July–September period
determined from the TSL rise and the observed balance gradient is 11–13 mm day−1 on Taku Glacier during the 2004–2010 period. The potential for
providing an estimate of bn from TSL observations late in the melt
season from satellite images combined with the frequent availability of such
images provides a means for efficient mass balance assessment in many years
and on many glaciers. |
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