FOR 1083: Multi-Scale Interfaces in Unsaturated Soil (MUSIS)

非饱和带内的水分分布和动态决定了从土壤剖面到大陆响应尺度上陆-气界面的能量平衡和关键质量通量。土壤水分的再分布和交换，如与上面的大气边界层的界面处的渗透和蒸发，或与下面的地下水的排水和补给，通常涉及穿过土壤层和通过非均匀边界的流体前缘的位移。目前的建模概念是不足以描述这种复杂的位移过程，通过天然非均质土壤高度非线性流动机制参与，从而限制了他们的预测能力，因为水-气界面可能会形成一个稳定的位移前或可能分裂成手指和优先流域，导致水分布和相关的运输途径的模式大不相同。核心工作假设是，移动的水-气界面在异质土壤结构和相互作用的相互竞争的驱动力之间的小尺度物理引起了广泛的水和气体动力学的宏观模式不捕获标准的连续介质模型。该研究单元的主要目标是将水和气体分布的特征模式作为以下函数进行表征和量化：

Water distribution and dynamics within the unsaturated zone determine energy balance and key mass fluxes at the land-atmosphere interface at scales ranging from soil profile to continental response. Soil water redistribution and exchanges such as infiltration and evaporation at the interface with the atmospheric boundary layer above, or drainage and recharge with groundwater below often involve displacement of fluid fronts across soil layers and through heterogeneous boundaries. Current modelling concepts are inadequate for describing such complex displacement processes through naturally-heterogeneous soils with highly non-linear flow mechanisms involved, thus limiting their predictive capabilities simply because water-air interfaces may form a stable displacement front or may split into fingers and preferential flow domains, leading to vastly different patterns of water distribution and associated transport pathways. The central working hypothesis is that small-scale physics of moving water-air interfaces within heterogeneous soil structures and interplay among competing driving forces give rise to a wide array of macroscopic patterns of water and gas dynamics not captured by standard continuum models. The primary objective of this Research Unit is to characterise and quantify characteristic patterns of water and gas distributions as a function of