Evaluating the impact of the Central Chile Mega Drought on debris cover, broadband albedo, and surface drainage system of a Dry Andes glacier

TL;DR

This study analyzes how the Central Chile Mega Drought has affected Universidad Glacier in the Dry Andes, revealing increased debris cover, glacier retreat, and changes in surface drainage, with implications for regional water resources.

Contribution

It introduces a novel spectral index for mapping surface rock material and provides detailed analysis of glacier surface changes during a major drought event.

Findings

Debris cover on the glacier's tongue has expanded and reached higher elevations.

The glacier's retreat is most pronounced at the margins and secondary accumulation cirques.

Stream density increases indicate enhanced melting and water supply.

Abstract

In recent years, Chile has experienced an extraordinary drought that has had significant impacts on both the livelihoods of people and the environment, including the Andean glaciers. This study focuses on analyzing the surface processes of Universidad Glacier, a benchmark glacier for the Dry Andes. Multiple remote sensing datasets are used alongside a novel spectral index designed for mapping of rock material located on the glacier's surface. Our findings highlight the precarious state of the glacier, which serves as a crucial water source for the region. The glacier exhibits locally varied debris accumulation and margin retreat. The most significant impacts are observed on the tongue and secondary accumulation cirques, with the latter at risk of disappearing. Debris cover on the tongue expands, reaching higher elevations, and is accompanied by glacier retreat, especially at higher altitudes. The equilibrium line is rapidly shifting upglacier, although mid-season snow cover tends to reach the 2013 equilibrium line even by 2020. Changes in stream density on the glacier's tongue indicate an increased water supply in this area, likely due to enhanced melting of glacial ice. These observed processes align well with meteorological data obtained from models. The behavior of dust and debris is influenced by precipitation amount, while the rate of retreat is linked to air temperature.