Influences of snow cover on thermal and mechanical processes in steep permafrost rock walls: internal response

最近在理想的未受干扰的永久冻土基岩的热模拟方面取得了重大成就。然而，大多数多年冻土岩壁继承了显著的积雪积累，这往往主导了多年冻土的演变和波动。气候变化改变了降雪的时间、持续时间和厚度，这些都影响了永久冻土的发展。我们的项目旨在破译陡峭的永久冻土中的积雪控制及其对气候变化的敏感性。我们的目标是开发1)一种新的方法/建模框架来研究雪强迫，2)对雪影响量化的过程理解，以及3)估计陡峭的永久冻土岩壁积雪变化影响的未来情景。第2部分侧重于使用连续积雪量化、地面激光扫描（TLS）、物理雪特性（雪坑）校准和表面岩石温度（温度记录仪）测量的地表热/水流特征。第1部分使用实验室校准的三维地球物理监测（电阻率和地震折射层析成像）以及不稳定和水机械力的声学、水力和岩土观测，研究了雪对岩壁内部热力学行为的地下影响。我们的目标是建立一个陡峭基岩中积雪覆盖和融雪的真实模型（SNOWPACK）和一个揭示裂隙基岩中融雪渗透的水热和水力学效应的耦合模型（UDEC）。模型结果将通过在积雪层、岩石表面和岩石地下（钻孔）的热和力学观测进行验证。这些模型对改变的降雪情景的敏感性将为气候变化对潜在危险的永久冻土岩面的影响提供更全面的看法。

Significant achievements have recently been made for thermal modelling of idealised undisturbed permafrost bedrock. However, most permafrost rock walls inherit significant snow accumulation, which often dominate permafrost evolution and fluctuation throughout time. Climate change alters snow timing, duration and thickness which all influence permafrost development. Our project aims at deciphering snow control in steep permafrost rocks and its sensitivity to climate change. We target at developing 1) a novel methodological/modelling framework to investigate snow forcing, 2) process understanding for snow impact quantification and 3) future scenarios for estimating the impact of snow cover changes in steep permafrost rock walls. Part 2 focuses on surface heat/water flow characterization using continuous snow cover quantification, terrestrial laser scanning (TLS), the calibration of physical snow properties (snow pits) and surface rock temperature (temperature loggers) measurements. Part 1 investigates the subsurface impact of snow on the thermal and mechanical behaviour inside rockwalls using laboratory-calibrated 3D geophysical monitoring (electrical resistivity and seismic refraction tomography) as well as acoustic, hydraulic and geotechnical observation of instability and hydro-mechanical forcing. We aim at developing a realistic model for snow cover and snow melt in steep bedrock (SNOWPACK) and a coupled model that reveals hydro-thermal and hydro-mechanical effects of snow melt infiltration in fractured bedrock (UDEC). Model results will be validated using thermal and mechanical observation in the snow cover, at the rock surface and in the rock subsurface (borehole). The sensitivity of the models to altered snow scenarios will provide a more holistic view on climate change impacts on potentially hazardous permafrost rock faces.