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Glacier sensitivity along the Andes: implication for paleoclimatic reconstructions of the Little Ice Age

Sagredo, Esteban A.

Abstract Details

2012, PhD, University of Cincinnati, Arts and Sciences: Geology.

Accompanying the drastic increase of global temperatures observed since the end of the nineteenth century, and particularly during the last decades, glaciers worldwide have experienced rapid retreating trend. Considering the magnitude of the climate change projected for the next decades, and the potential impacts of glacier retreat on human livelihood, a thorough comprehension of climate-glacier interaction is critical in order to i) predict the response of glaciers to the different scenarios of climate change and ii) reconstruct the climatic conditions associated with former glacial fluctuations, which in turn could provide important background information for the study of both natural cycles and human impacts on climate change. This study explores the magnitude of response of the equilibrium line altitude (ELA) to different scenarios of climate change, along the climatically diverse Andes range, and its applicability to reconstruct paleoclimates.

A statistical analysis of the climatic conditions at 234 glacier sites permits to classify the climate that host present-day Andean glaciers into seven groups. These groups have a distinctive geographical distribution. It has been suggested that glaciers located in different climates could respond with different magnitude to similar climatic perturbations. Here, a full-surface energy and mass balance (SEMB) model was applied to quantify the ELA sensitivity to climate across glaciated Andean regions. The results suggest that there is spatial variability in the magnitude of response of the ELA to uniform changes in temperature and precipitation, and that the spatial pattern of this variability has a general correspondence with the climatic groups identified along the Andes. The most sensitive areas to changes in temperature are the inner tropics, whereas precipitation sensitivities are relatively greater in the subtropics and northernmost mid-latitudes.

It is suggested that the variability in the ELA sensitivity has implications for the reconstruction of paleoclimates across large areas. Based on an approach that combine the geomorphic reconstruction of ELA of Andean glaciers and the application of the SEMB model, different scenarios of climatic conditions for the maximum glacial advance occurred during the Little Ice Age (LIA, sensu lato AD 1300-1850) are suggested. To conduct this experiment, three glacial sites (located in different climatic regimes) were selected: Cordillera Vilcanota (13¿¿¿¿S), Cipreses glacier (34¿¿¿¿S) and Tranquilo glacier (47¿¿¿¿S). The results consist of a set of combination of temperature and precipitation anomalies that can account for ELA changes from the maximum glacial advance that occurred during the LIA to the present for each site. Assuming no changes in precipitation, the ELA fluctuation since the LIA could be explained by a cooling of at least: -0.7¿¿¿¿C at Vilcanota, -0.5¿¿¿¿C at Cipreses and -1.3¿¿¿¿C at Tranquilo glacier. Assuming no changes in temperature, on the other hand, the ELA changes could be explained by an increase in the precipitation greater than 63% at Vilcanota, 21% at Cipreses and 62% at Tranquilo glacier. Finally, it is expected that the integration of these analysis provides a framework to understand former episodes of glacial fluctuation, as well as to predict the response of glacier to different scenarios of climate change.

Thomas Lowell, PhD (Committee Chair)
Michael Kaplan, PhD (Committee Member)
Patricio Moreno, PhD (Committee Member)
Warren Huff, PhD (Committee Member)
Lewis Owen, PhD (Committee Member)
109 p.

Recommended Citations

Citations

  • Sagredo, E. A. (2012). Glacier sensitivity along the Andes: implication for paleoclimatic reconstructions of the Little Ice Age [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1342103681

    APA Style (7th edition)

  • Sagredo, Esteban. Glacier sensitivity along the Andes: implication for paleoclimatic reconstructions of the Little Ice Age. 2012. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1342103681.

    MLA Style (8th edition)

  • Sagredo, Esteban. "Glacier sensitivity along the Andes: implication for paleoclimatic reconstructions of the Little Ice Age." Doctoral dissertation, University of Cincinnati, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1342103681

    Chicago Manual of Style (17th edition)