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| Titel |
Atmospheric warming at a high-elevation tropical site revealed by englacial temperatures at Illimani, Bolivia (6340 m above sea level, 16°S, 67°W) |
| VerfasserIn |
Adrien Gilbert, Patrick Wagnon, Christian Vincent, Patrick Ginot, Martin Funk |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250076374
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| Zusammenfassung |
| In June 1999, a deep (138.7 m) ice core was extracted from the summit glacier of Illimani,
Bolivia (6340 m above sea level, 16°39’S, 67°47’W), and an englacial temperature
profile was measured in the borehole. Using on-site and regional meteorological
data as well as ice core stratigraphy, past surface temperatures were reconstructed
with a heat flow model. The englacial temperature measurements exhibit a profile
that is far from a steady state, reflecting an increasing atmospheric temperature
over several years and nonstationary climatic conditions. Englacial temperature
interpretation,using air temperature data, borehole temperature inversion, and melting rate
quantification based on ice core density, shows two warming phases from 1900 to 1960
(+0.5 ± 0.3 K starting approximately in 1920-1930) and from 1985 to 1999 (+0.6
± 0.2 K), corresponding to a mean atmospheric temperature rise of 1.1 ± 0.2 K
over the 20th century. According to various climate change scenarios, the future
evolution of englacial temperatures was simulated to estimate when and under what
conditions this high-elevation site on the Illimani summit glacier could become
temperate in the future. Results show that this glacier might remain cold for more
than 90 years in the case of a +2 K rise over the 21st century but could become
temperate in the first 20 m depth between 2050 and 2060 if warming reaches +5 K. |
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