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| Titel |
A new method for deriving glacier centerlines applied to glaciers in Alaska and northwest Canada |
| VerfasserIn |
C. Kienholz, J. L. Rich, A. A. Arendt, R. Hock |
| 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 ; 8, no. 2 ; Nr. 8, no. 2 (2014-03-25), S.503-519 |
| Datensatznummer |
250116082
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| Publikation (Nr.) |
 copernicus.org/tc-8-503-2014.pdf |
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| Zusammenfassung |
| This study presents a new method to derive centerlines for the main branches
and major tributaries of a set of glaciers, requiring glacier outlines and a
digital elevation model (DEM) as input. The method relies on a "cost grid–least-cost route approach" that comprises three main steps. First, termini
and heads are identified for every glacier. Second, centerlines are derived
by calculating the least-cost route on a previously established cost grid.
Third, the centerlines are split into branches and a branch order is
allocated. Application to 21 720 glaciers in Alaska and northwest Canada
(Yukon, British Columbia) yields 41 860 centerlines. The algorithm performs
robustly, requiring no manual adjustments for 87.8% of the glaciers. Manual
adjustments are required primarily to correct the locations of glacier heads
(7.0% corrected) and termini (3.5% corrected). With corrected heads and
termini, only 1.4% of the derived centerlines need edits. A comparison of
the lengths from a hydrological approach to the lengths from our longest
centerlines reveals considerable variation. Although the average length ratio
is close to unity, only ~ 50% of the 21 720 glaciers have the two
lengths within 10% of each other. A second comparison shows that our
centerline lengths between lowest and highest glacier elevations compare well
to our longest centerline lengths. For > 70% of the 4350 glaciers with
two or more branches, the two lengths are within 5% of each other. Our final
product can be used for calculating glacier length, conducting length change
analyses, topological analyses, or flowline modeling. |
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