Title

Short-Term Climate Cycles, Recent Climate Changes, and Volcano-Ice Hazards : Nevado Coropuna, Arequipa, Peru

Date of Award

5-22-2016

Document Type

Honors Thesis

Department

Earth Sciences

Language

English

Abstract

The glacier body atop Nevado Coropuna Peru is the largest body of ice in the tropics. The surrounding area is home to ~100,000 people and is vital for agricultural production in southern Peru. Not only does the ice cap provide a water resource to Peruvians in the area, but it also poses a potential hazard if the volcano erupts. The location and physiography of Coropuna make it an excellent location to understand local climate over a variety of timescales in the ice and snow. Using 258 Landsat scenes, to measure snow and ice extent at Coropuna since 1980, this study has suggested a more accurate measure of glacial shrinking on Coropuna. During fieldwork in 2015, we collected nitrogen and diatom samples, made observations of millennial scale lava flows, and collected century scale lake sediment cores. In additional, this study uses photographs of ice retreat for historic comparison, and measured ice thickness at an outcrop.

An analysis of 20 Landsat images from 1980 to 2014 to measure aerial changes in the ice cap at the Nevado Coropuna volcanic complex, Peru suggests ice loss to be 0.41 km2 yr-1. Even though previous studies have reported ice loss rates of 1.4 km2/yr. Analysis of 258 Landsat scenes determined annual snow minimums using the Normalized Difference Snow Index. Field photographs estimate that a western outcrop of ice is 37 meters, and provide useful supplemental information to work by others including Peduzzi et al (2010) and Birkos (2009). While testing of N during the 2015 field season was inconclusive, preliminary diatom analysis is promising and in progress. Although some predict that Coropuna will be a non-contributor to water supply by 2025, my results suggest that this will not be the case and that the ice-cap could survive at present rates for the remainder of this century and beyond. My results have significant implications for hazard assessment and resource water planning in southern Peru, which relies heavily on glacial meltwater for year round agricultural production and domestic use.

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