Seeing the forest for the trees: Interpreting and quantifying emergent catchment hydrology behavior

一个统一的理论描述主要控制山区流域水文响应继续逃避水文学家，尽管有价值的进展，定量建模和过程的理解，从漫流，通流，变量源区动态。这可能是由于自然系统的近乎无限的复杂性，我们无法充分测量必要的变量在空间和时间，以及在量化非线性流域过程和阈值介导的径流产生的困难。我们承认迄今为止在集水过程理解和建模方面取得的进展，并致力于扩大我们对系统行为理解的局限性，并开发混合概念（数学）模型，这些模型通过综合过程观察进行内部验证和测试。我们正在蒙大拿州中部小带山脉的嫩脚溪实验森林（TCEF）进行一系列的经验和建模研究，这些研究在七个相邻的不同流域和五年多的可变气候强迫中反复进行。我们具体解决以下问题的流域水文学的挑战：1）景观结构（形状）在水源山流域水文响应和水源水的贡献？后续：结构的相对重要性是否在变量强迫（气候变率）中发生变化？2)我们能否根据景观结构在流域响应中的作用的假设，开发新的流域行为的量化（模型）？后续：现场观察如何帮助推断特定的模型结构和参数，并限制预测的不确定性？3)基于景观结构的集水模型的有效性是否在多个集水区或不同的气候强迫下有所不同？后续：我们如何比较新模型概念化与基于地形控制、可变源区概念或简单水平衡表示的传统模型的可移植性？为了应对这些挑战，我们正在努力为研究和教育建立工具和基础设施。我们专注于流域科学的关键主题，通过新的过程概念化和模型结构来提高流域理解的可转移性和流域响应的可预测性。

A unifying theory describing primary controls on mountain catchment hydrologic response continues to elude hydrologists despite valuable advances in quantitative modeling and process understanding from overland flow, to throughflow, to variables source area dynamics. This may be attributed to the near infinite complexities of natural systems, our inability to measure necessary variables adequately in space and time, and difficulties in quantifying non-linear watershed processes and threshold mediated runoff generation. We acknowledge the advances to date in catchment process understanding and modeling and are engaged in activities focused on both expanding the limits of our system behavior understanding and developing hybrid conceptual (mathematical) models internally validated and tested with synthesized process observations. We are conducting a suite of empirical and modeling studies performed iteratively at the Tenderfoot Creek Experimental Forest (TCEF) in the Little Belt Mountains of central Montana, across seven adjacent diverse watersheds and more than five years of variable climatic forcings. We specifically address the following challenges in catchment hydrology:1) What is the role of landscape structure (shape) in headwater mountain catchment hydrologic response and source water contributions? Follow-on: Does the relative importance of structure change across variable forcing (climatic variability)?2) Can we develop new quantifications (models) of watershed behavior based on hypotheses about the role of landscape structure in watershed response? Follow-on: How do field observations help infer specific model structures and parameters, and constrain predictive uncertainty?3) Does the effectiveness of catchment models based on landscape structure vary across multiple watersheds or under different climatic forcing? Follow-on: How do we compare the transferability of new model conceptualizations to traditional models based on topographic controls, variable source area concepts, or simple water balance representations?To address these challenges we are working to build tools and infrastructure for research and education. We focus on themes critical to watershed science to improve transferability of watershed understanding and predictability of watershed response via new process conceptualizations and model structures.