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

近年来，在理想化的原状冻土基岩热模拟方面取得了重要成果。然而，大多数多年冻土岩壁继承了显着的积雪，往往主导多年冻土的演变和波动。气候变化会改变降雪的时间、持续时间和厚度，这些都会影响永久冻土的发展。我们的项目旨在破译陡峭的永久冻土岩石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，以调查雪强迫，2）雪影响量化的过程理解和3）未来的情况下，估计积雪变化的影响，在陡峭的永久冻土岩壁。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）测量来表征表面热量/水流。第1部分使用实验室校准的3D地球物理监测（电阻率和地震折射层析成像）以及对不稳定性和水力机械力的声学、水力和土工观察，研究雪对岩壁内部热和力学行为的地下影响。我们的目标是开发一个现实的模型，在陡峭的基岩（SNOWPACK）和耦合模型，揭示了水热和水力机械的影响，在破碎的基岩（UDEC）的雪融水渗透。模型结果将通过积雪、岩石表面和岩石地下（钻孔）的热和机械观测进行验证。模型对积雪变化情景的敏感性将为气候变化对潜在危险的永久冻土岩石表面的影响提供更全面的观点。

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.