Equilibrium line altitudes along the Andes during the Last millennium: Paleoclimatic implications
Malone, Andrew G. O.
- 1Pontificia Universidad Catolica de Chile
- 2University System of Ohio
- 3Dartmouth College
- 4Utah System of Higher Education
- 5
- 6University of Chicago
Journal
Holocene
ISSN
0959-6836
1477-0911
Open Access
green
Volume
27
Start page
1019
End page
1033
Deciphering the climate changes that influenced the glacial fluctuations of the last millennium requires documenting the spatial and temporal patterns of these glacial events. Here, we estimate the change in equilibrium line altitudes (ELAs) between the most prominent glacial advance of the last millennium and the present for four alpine glaciers located in different climatic regimes along the Andes. For each glacier, we reconstruct scenarios of climatic conditions (temperature and precipitation anomalies) that accommodate the observed ELA changes. We focus on the following glaciers: an alpine glacier in the Cordillera Vilcanota (13 degrees S), Tapado glacier (30 degrees S), Cipreses glacier (34 degrees S), and Tranquilo glacier (47 degrees S). Our results show that the range of possible temperature and precipitation anomalies that accommodate the observed ELA changes overlap significantly at three of the four sites (i.e. Vilcanota, Cipreses, and Tranquilo). Only Tapado glacier exhibits a set of climate anomalies that differs from the other three sites. Assuming no change in precipitation, the estimated ELA changes require a cooling of at least 0.7 degrees C in the Cordillera Vilcanota, 1.0 degrees C at Tapado glacier, 0.6 degrees C at Cipreses glacier, and 0.7 degrees C at Tranquilo glacier. Conversely, assuming no change in temperature, the estimated ELA changes are explained by increases in precipitation exceeding 0.52 m yr(-1) (64% of the annual precipitation) in the Cordillera Vilcanota, 0.31 m yr(-1) (89%) at Tapado glacier, 0.22 m yr(-1) (27%) at Cipreses glacier, and 0.3 m yr(-1) (27%) at Tranquilo glacier. By mapping the ELA changes and modeling the potential climate forcing across diverse climate settings, we aim to contribute toward documenting the spatial variability of climate conditions during the last millennium, a key step to decipher the mechanisms underlying the glacial fluctuation that occurred during this period.
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