Integrated surface-subsurface hydrologic modelling of fluid flow, solute and thermal transport

地下水和地表水系统中流体的流动和污染物或热能的传播模式受到水力参数、多组分化学反应过程和大气输入的空间变异性的强烈影响。地表和地下水流制度本身是相互耦合的，为预测陆上、河流和可变饱和的地下水流速率以及污染物和热能交换通量而设计的现实计算模型还必须适应复杂的地形、土地利用/土地覆盖的时空变化和阶段性或长期的强迫作用，所有这些都在分流域到分水岭到大陆的三维尺度上。我最近在处理涉及强耦合系统的问题的计算水文地质学/水文学方面取得的进展，使我们能够在数百至数千平方公里甚至更远的范围内，以前所未有的3D细节探索手头的许多突出问题。为了深入了解非均匀地表/地下水流系统中大气/地表/地下交换过程的行为，将对地表水和地下水科学家面临的各种当代问题进行高分辨率数值模拟，包括对监测良好的流域的模型应用。拟议的研究将集中在水量和水质问题上。我的研究小组一直在积极开发和应用新的3D数值求解策略，以在一个集成的地表/地下建模框架中求解描述流体流动、质量和热传输的高度非线性偏微分方程组。我们的3D全集成地表/地下模型--水地球球体是最先进的，被科学界广泛使用。由于现有气候模型不能反映饱和区地下水流动的动态和地表水的渗入/渗出的复杂模式，以及河流、湿地和水体之间的相关地下水相互作用，正在将一个平行版本的水文地球球体与几个众所周知的气候模型完全结合起来。

Fluid flow and spreading patterns of contaminants or thermal energy in groundwater and surface water systems are strongly influenced by the spatial variability of hydraulic parameters, multi-component chemical reaction processes and atmospheric inputs. In the context of surface and subsurface flow regimes, which are inherently coupled, realistic computational models designed to predict overland, stream and variably-saturated subsurface flow rates and contaminant and thermal energy exchange fluxes must also accommodate complex topography, spatial and temporal variations in land use/land cover and episodic or long-term forcing functions, all at the sub-watershed to watershed to continental scales in three dimensions. My recent strides in computational hydrogeology/hydrology to address problems involving strongly coupled systems have uniquely positioned us to explore many of the salient issues at hand in unprecedented detail in 3D at scales ranging from hundreds to thousands of square kilometres and beyond. In order to gain insight into the behaviour of atmospheric/surface/subsurface exchange processes in heterogeneous surface/subsurface flow systems, high-resolution numerical simulations of a variety of contemporary problems facing surface water and groundwater scientists, including model applications to well-monitored watersheds, will be performed. The proposed research will focus on both water quantity and quality issues. My research group has been actively developing and applying new 3D numerical solution strategies to solve the highly nonlinear partial differential equations describing fluid flow, mass and heat transport in an integrated surface/subsurface modelling framework. Our 3D fully-integrated surface/subsurface model HydroGeoSphere is state-of-the-art and is widely used by the scientific community. Full coupling of a parallel version of HydroGeoSphere to several well-known climate models is being performed because existing climate models fail to represent the dynamics of saturated-zone groundwater flow and the complex patterns of water infiltration/exfiltration over the land surface and related groundwater interactions between streams, wetlands and water bodies.