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| Titel |
Multi-century lake area changes in the Southern Altiplano: a tree-ring-based reconstruction |
| VerfasserIn |
M. S. Morales, J. Carilla, H. R. Grau, R. Villalba |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 11, no. 9 ; Nr. 11, no. 9 (2015-09-15), S.1139-1152 |
| Datensatznummer |
250117401
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| Publikation (Nr.) |
 copernicus.org/cp-11-1139-2015.pdf |
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| Zusammenfassung |
| Size fluctuations in endorheic lakes in northwestern Argentina (NWA) and
southwestern Bolivia (SWB) are very sensitive to basin hydrological balances,
and consequently, very vulnerable to deleterious effects from climatic
changes. The management of these water resources and their biodiversity
requires a comprehensive knowledge of their natural variability over multiple
timescales. In this study, we present a multi-century reconstruction of past
lake-area fluctuations in NWA and SWB. The evidence used to develop and
validate this reconstruction includes satellite images and a century-long
tree-ring record from P. tarapacana. Inter-annual fluctuations in
lake area of nine lakes were quantified based on Landsat satellite images
over the period 1975 to 2009. A regional P. tarapacana tree-ring
chronology, composite from two sampling sites, was used as predictors in a
regression model to reconstruct the mean annual (January–December) lake area
from the nine lakes. The reconstruction model captures 62 % of the total
variance in lake-area fluctuations and shows adequate levels of
cross-validation. This high-resolution reconstruction covers the past
601 years
and characterizes the occurrence of annual to multi-decadal lake area
fluctuations and its main oscillation modes of variability. Our
reconstruction points out that the late 20th century decrease in lake area
was exceptional over the period 1407–2007; a persistent negative trend in
lake area is clear in the reconstruction and consistent with glacier retreat
and other climate proxies from the Altiplano and the tropical Andes. Since
the mid 1970s, the Vilama-Coruto lake system recorded an accelerated decrease
in area consistent with an increasing recurrence of extremely small lake-area
events. Throughout the 601 years, the reconstruction provides valuable
information about spatial and temporal stabilities of the relationships
between changes in lake area, ENSO, and PDO, highlighting the Pacific
influence over most modes of lake area variability. Global and regional
climate models for the Altiplano project a marked reduction in precipitation
to the end of the 21st century, exacerbating presently dry conditions. These
results provide a baseline for the historical range of variability in lake
fluctuations and thus should be considered for the management of biodiversity
and water resources in the Central Andes during the next decades. |
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