Status and evolution of the cryosphere in the Andes of Santiago (Chile, 33.5°S.)

被引:57
作者
Bodin, X. [1 ,2 ]
Rojas, F. [1 ,2 ]
Brenning, A. [2 ]
机构
[1] Pontificia Univ Catolica Chile, Inst Geog, Santiago, Chile
[2] Univ Waterloo, Dept Geog & Environm Management, Waterloo, ON N2L 3G1, Canada
基金
加拿大自然科学与工程研究理事会;
关键词
Rock glacier; Debris-covered glacier; Thermokarst; Downwasting; Mountain permafrost; Ground temperature monitoring; ROCK-GLACIERS; INTERNAL STRUCTURE; PERMAFROST; MENDOZA; CLIMATE; ROCKGLACIER; MOUNTAINS; CREEP;
D O I
10.1016/j.geomorph.2010.02.016
中图分类号
P9 [自然地理学];
学科分类号
0705 ; 070501 ;
摘要
In the context of a general retreat of glaciers in the dry Andes, this study focuses on the state and recent evolution of debris-covered glaciers and permafrost-related landforms, especially rock glaciers, in the semiarid to semihumid Laguna Negra catchment, a part of the Andes of central Chile at 33.5 degrees S, that is a key contributor of drinking water for the city of Santiago. We conducted catchment-scale geomorphological mapping, diachronic analysis of 1955 and 1996 orthophotographs and digital elevation models (DEMs), and the analysis of ground temperatures and their sensitivity to climate variation. Rock glaciers dominate spatially and in terms of water storage over glaciers (area ratio: 1.7:1; ratio of water equivalents: 1.5:1). An intense downwasting has affected both debris-covered and exposed glacier components in the Punta Negra subcatchment, a process that is associated with the growth of numerous thermokarst depressions. The altitudinal transect of ground temperature suggest that permafrost is widespread above similar to 4000 m asl, although it can also occur at lower elevations on sheltered footslopes and within rock glaciers. The sensitivity analysis indicates that the near-surface ground thermal regime at high altitudes is strongly influenced by the snow cover disappearance date, which may therefore constitute an important control on the effect of climatic warming. (C) 2010 Elsevier B.V. All rights reserved.
引用
收藏
页码:453 / 464
页数:12
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