Alpine permafrost environments are highly vulnerable and sensitive to changes in regional and global climate trends. Thawing and degradation of permafrost has numerous adverse environmental, economic, and societal impacts. Mathematical modeling and numerical simulations provide powerful tools for predicting the degree of degradation and evolution of subsurface permafrost as a result of global warming. A particularly significant characteristic of alpine environments is the high variability in their topography and geomorphology which drives large lateral thermal and fluid fluxes. Additionally, harsh winds, extreme weather conditions, and various degrees of saturation have to be considered. The combination of large lateral fluxes and unsaturated ground makes alpine systems markedly different from Arctic permafrost environments and general geotechnical ground freezing applications, and therefore, alpine permafrost demands its own specialized modeling approaches. In this research work, we present a multi-physics permafrost model tailored to alpine regions. In particular, we resolve the ice-water phase transitions, unsaturated conditions, and capillary actions, and account for the impact of the evolving pore volume on fluid-matrix interactions. Moreover, the approach is multi-dimensional, and therefore, inherently resolves fluxes along topographic gradients. Through numerical cases studies based on the elevation profiles of the two prominent peaks of the Zugspitze (DE) and the Matterhorn (CH), we show the strong influence of topography driven thermal and fluid fluxes on active layer dynamics and the distribution of permafrost.

翻译：Alpine permafrost环境非常脆弱,而且对区域和全球气候趋势的变化十分敏感。永久冻土的变化和退化对环境、经济和社会产生了许多不利的影响。数学模型和数字模拟为预测全球变暖导致表层下永久冻土退化和演变的程度提供了强有力的工具。高山环境的一个特别显著的特点是其地形和地貌形态的高度变异性导致大量的横向热流和流体通量。此外,还必须考虑到严酷的风、极端的天气条件和不同程度的饱和。大型的横向通量和不饱和地表的结合使得高山系统与北极的永久冻土环境及一般地铁冻结应用明显不同,因此,高山地冻土需要其自身的专门建模方法。在这一研究工作中,我们展示了一个适合高山地区的多物理永久冻土模型模型。特别是,我们解决了冰水阶段的转变、不饱和条件以及不同程度的饱和饱和程度。大量横向流动的土壤动态和地表层变化过程,从而展示了不断演化的平流性变化。