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| Titel |
Glacial areas, lake areas, and snow lines from 1975 to 2012: status of the Cordillera Vilcanota, including the Quelccaya Ice Cap, northern central Andes, Peru |
| VerfasserIn |
M. N. Hanshaw, B. Bookhagen |
| 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 (2014-03-03), S.359-376 |
| Datensatznummer |
250116073
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| Publikation (Nr.) |
 copernicus.org/tc-8-359-2014.pdf |
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| Zusammenfassung |
| Glaciers in the tropical Andes of southern Peru have received limited
attention compared to glaciers in other regions (both near and far), yet
remain of vital importance to agriculture, fresh water, and hydropower
supplies of downstream communities. Little is known about recent glacial-area
changes and how the glaciers in this region respond to climate changes, and,
ultimately, how these changes will affect lake and water supplies. To remedy
this, we have used 158 multi-spectral satellite images spanning almost 4
decades, from 1975 to 2012, to obtain glacial- and lake-area outlines for the
understudied Cordillera Vilcanota region, including the Quelccaya Ice Cap.
Additionally, we have estimated the snow-line altitude of the Quelccaya Ice
Cap using spectral unmixing methods. We have made the following four key
observations: first, since 1988 glacial areas throughout the Cordillera
Vilcanota (1988 glacial area: 361 km2) have been declining at a rate of
3.99 ± 1.15 km2 yr−1 (22 year average, 1988–2010, with
95% confidence interval (CI), n = 8 images). Since 1980, the Quelccaya
Ice Cap (1980 glacial area: 63.1 km2) has been declining at a rate of
0.57 ± 0.10 km2 yr−1 (30 year average, 1980–2010, with
95% CI, n = 14). Second, decline rates for individual glacierized
regions have been accelerating during the past decade (2000–2010) as
compared to the preceding decade (1988–1999) with an average increase from
37.5 to 42.3 × 10−3 km2 yr−1 km−2 (13%).
Third, glaciers with lower median elevations are declining at higher rates
than those with higher median elevations. Specifically, glaciers with median
elevations around 5200 m a.s.l. are retreating to higher elevations at a
rate of ~1 m yr−1 faster than glaciers with median elevations
around 5400 m a.s.l. Fourth, as glacial regions have decreased, 77% of
lakes connected to glacial watersheds have either remained stable or shown a
roughly synchronous increase in lake area, while 42% of lakes not
connected to glacial watersheds have declined in area (58% have remained
stable). Our new and detailed data on glacial and lake areas over 37 years
provide an important spatiotemporal assessment of climate variability in this
area. These data can be integrated into further studies to analyze
inter-annual glacial and lake-area changes and assess hydrologic dependence
and consequences for downstream populations. |
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