Abstract
Abstract. Since 2003, a monitoring program has been conducted on several glaciers and glacierets in the Pascua-Lama region of the Chilean Andes (29° S/70° W; 5000 m a.s.l.), permitting the study of glaciological processes on ice bodies in a subtropical, arid, high-elevation area where no measurements were previously available. In this paper we present: (1) six years of glaciological surface mass balance measurements from four ice bodies in the area, including a discussion of the nature of the studied glaciers and glacierets and characterization of the importance of winter mass balance to annual mass balance variability; and (2) changes in surface area of twenty ice bodies in the region since 1955, reconstructed from aerial photographs and satellite images, which shows that the total glaciated surface area reduced by ~29% between 1955 and 2007, and that the rate of surface area shrinkage increased in the late 20th century. Based on these datasets we present a first interpretation of glacier changes in relation with climatic parameters at both local and regional scales.
Highlights
In the arid to semi-arid subtropical region of Chile and Argentina (27◦ S to 33◦ S), the evolution of the cryosphere is a major concern for local populations due to the impact on wa-ter resources
The winter mass balance is calculated in early spring from: (1) snow depth and density measurements obtained by a combination of snow cores and probing at each stake site on the ice bodies; (2) stake emergence measurement; and (3) one or two snow pits are sampled on each glacier(et) depending on the size of the ice body
We present and discuss results of the mass balance monitoring to characterize the climate-glacier relationship in semi-arid climate conditions
Summary
In the arid to semi-arid subtropical region of Chile and Argentina (27◦ S to 33◦ S), the evolution of the cryosphere (including glaciers, rock glaciers and seasonal snow cover) is a major concern for local populations due to the impact on wa-ter resources. Glaciers in Pascua-Lama region are generally small, and the term “glacieret” is often adapted. This term defines a very small ice body, typically less than 0.25 km in extent, with no marked flow pattern visible at the surface, usually occupying sheltered parts of the landscape and formed primarily by drifting snow and avalanches (Cogley et al, 2011). Climate conditions are considerably drier in the Pascua-Lama region than those observed 450 km south on Echaurren Glacier or on the Argentinian side of the Andean divide on Piloto Glacier (Falvey and Garreaud, 2007; Favier et al, 2009). Glaciological processes are likely to be different in this transition zone and studying the glaciers of this region is crucial to understand the role of glaciers in the hydrological cycle.
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