文章基本信息

标题：Rock glaciers on the run – understanding rock glacier landform evolution and recent changes from numerical flow modeling
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作者：Johann Müller ; Andreas Vieli ; Isabelle Gärtner-Roer 等
期刊名称：The Cryosphere
印刷版ISSN：1994-0416
电子版ISSN：1994-0424
出版年度：2016
卷号：10
期号：6
页码：2865-2886
DOI：10.5194/tc-10-2865-2016
出版社：Copernicus Publications
摘要：Rock glaciers are landforms that form as a result of creeping mountain permafrost which have received considerable attention concerning their dynamical and thermal changes. Observed changes in rock glacier motion on seasonal to decadal timescales have been linked to ground temperature variations and related changes in landform geometries interpreted as signs of degradation due to climate warming. Despite the extensive kinematic and thermal monitoring of these creeping permafrost landforms, our understanding of the controlling factors remains limited and lacks robust quantitative models of rock glacier evolution in relation to their environmental setting. Here, we use a holistic approach to analyze the current and long-term dynamical development of two rock glaciers in the Swiss Alps. Site-specific sedimentation and ice generation rates are linked with an adapted numerical flow model for rock glaciers that couples the process chain from material deposition to rock glacier flow in order to reproduce observed rock glacier geometries and their general dynamics. Modeling experiments exploring the impact of variations in rock glacier temperature and sediment–ice supply show that these forcing processes are not sufficient to explain the currently observed short-term geometrical changes derived from multitemporal digital terrain models at the two different rock glaciers. The modeling also shows that rock glacier thickness is dominantly controlled by slope and rheology while the advance rates are mostly constrained by rates of sediment–ice supply. Furthermore, timescales of dynamical adjustment are found to be strongly linked to creep velocity. Overall, we provide a useful modeling framework for a better understanding of the dynamical response and morphological changes of rock glaciers to changes in external forcing.