Improving process representation and numerics for integrated hydrological modeling at the subsurface/land surface/atmosphere interface

研究重点是地下/地表/大气界面模拟模式的开发与应用。目标将是从物理（过程表示和参数化）和数值（鲁棒性，准确性和效率）的角度推进综合水文和生态水文建模的最新技术。这项工作将基于少数几个公认的、完全分布的、基于物理的耦合水文模型之一，该模型使用先进的计算算法来解决地表和地下水流和溶质运输的控制质量守恒方程。工作的主要主题，也将成为个人博士和博士后研究项目的基础，将包括：不同复杂性的传质和传输现象；将额外的生态水文过程纳入现有模式；适当解决不同子系统之间的交换或耦合项；将模型现有的用于数据同化的集成框架扩展到参数估计和灵敏度分析；并将该模型应用于从农田到流域的多尺度和嵌套尺度。将解决集成的、基于过程的水文建模中的挑战，包括异质性、网格分辨率效应、相互竞争的子模型或参数化方案、强非线性和边界条件。模型的性能将根据不同的状态变量进行评估，包括流量和排放口的溶质浓度、系统总储水量和溶质质量、地下水总补给等综合措施，以及沿传感器网络不同点的土壤湿度、质量浓度和交换通量等分布式响应。该项目将依赖于来自试验山坡和流域尺度研究地点的详细、多元观测数据的可用性。该研究将在国际层面上进行高度合作，并将包括参与多学科实地实验和模型相互比较和基准研究。研究界对可靠的、可扩展的、开放的源代码有很高的需求，这些代码可以解决基于一致和严格的物理（和化学/生物）、数学和数值原理的综合生态水文过程。拟议的研究将导致改进模拟模型，以帮助我们加深对复杂自然现象的理解，不同过程如何相互作用，以及这些系统如何受到人为压力和其他因素的影响。

The proposed research will focus on the development and application of simulation models at the subsurface/land surface/atmosphere interface. The objective will be to advance the state of the art in integrated hydrological and ecohydrological modeling from both physical (process representation and parameterization) and numerical (robustness, accuracy, and efficiency) perspectives. The work will be based on one of only a handful of accepted, fully-distributed, physically-based, coupled hydrological models that use advanced computational algorithms to resolve the governing mass conservation equations for surface and subsurface water flow and solute transport. The main themes of the work, which will also be the bases for individual PhD and postdoctoral research projects, will include: mass transfer and transport phenomena of varying complexity; incorporation of additional ecohydrological processes into the existing model; proper resolution of exchange or coupling terms between different subsystems; extension of the model’s existing ensemble framework, implemented for data assimilation, to parameter estimation and sensitivity analysis; and applications of the model across multiple and nested scales, from field plot to river basin. Challenges in integrated, process-based hydrological modeling related to heterogeneity, grid resolution effects, competing submodel or parameterization schemes, strong nonlinearities, and boundary conditions will be addressed. Model performance will be assessed for different state variables, both integrated measures such as flow rate and solute concentration at the discharge outlet, total system water storage and solute mass, and total groundwater recharge, and distributed responses such as soil moisture, mass concentration, and exchange fluxes at different points along a sensor network. The project will rely on the availability of detailed, multivariate observation data from experimental hillslope and watershed scale study sites. The research will be highly collaborative at an international level and will include participation in multidisciplinary field experiments and model intercomparison and benchmarking studies. There is high demand in the research community for reliable, extendable, open source codes that can resolve integrated ecohydrological processes based on consistent and rigorous physical (and chemical/biological), mathematical, and numerical principles. The proposed research will result in improved simulation models to help us deepen our understanding of complex natural phenomena, of how different processes interact, and of how these systems can be impacted by anthropogenic stresses and other factors.