Prediction of Dynamic Ice Processes in Complex River Systems

河流冻结和解冻过程中的冰过程可以是非常动态的，极大地影响河流系统的水文、形态和生态过程。一个这样的过程是锚冰的演变，当湍急的水冷却到略低于0°C时，锚冰就会在河床上形成，这往往是短暂的，可能对鱼类栖息地和水资源基础设施(如水电设施)产生不利影响。另一个动态过程是冰塞的形成。冰塞是厚厚的碎冰堆积，压缩了河流的流动，因此经常与高洪水风险有关。多渠道系统，如河流三角洲和汇流，特别容易发生冰堵。例如，最近的麦克默里堡洪水是由于阿萨巴斯卡-克利尔沃特河汇合处形成的冰堵造成的。冰与水流和河流形态相互作用的复杂方式，使得观测和预报这些动态冰事件变得非常困难。关于多航道系统中锚冰演化和冰塞形成的过程，仍有许多悬而未决的问题。提高我们对这些动态冰事件的预测能力是非常有必要的。气候变化使这一问题变得更加紧迫，因为预计这些冰川事件的时间、频率和严重程度都将发生变化。基于物理的数值模型提供了强大的预测工具，当与良好的实验室和现场数据一起使用时，也可以为这些复杂的过程提供更好的见解。因此，我正在提出一项研究计划，通过开发基于物理的建模方法、进行实验室实验和/或利用现场数据来解决与冰塞和锚冰过程相关的知识空白。长期目标是显著提高我们对复杂河流环境中动态冰川过程的理解和预测能力。短期目标是：(1)调查河流三角洲在冰川堵塞期间发生的动态过程。(2)开发预报易冰堵多航道系统洪水风险的业务模型。(3)确定控制锚冰形成和释放机制的气象水文因素。(4)评估和改进现有河冰模型的锚冰算法。拟议的研究计划将提高对冰塞和锚冰事件的理解和预测能力。它将极大地有利于水利基础设施的开发和运营，并通过减少这些冰情的不利影响而具有重大的经济价值。它将提供可靠的洪水预报工具，减少洪水损失，从而立即造福于公众安全。这项研究将产生一个增强的、基于物理的河冰数值模式，它将为评估人类活动或气候变化对北方河流冰情的影响提供必要的工具。该项目还将为研究生和本科生团队提供高质量的培训。

Ice processes during river freeze-up and breakup can be very dynamic, greatly affecting the hydrological, morphological, and ecological processes in river systems. One such process is the evolution of anchor ice, which forms on the riverbeds when turbulent water cools to just below 0°C. It is often ephemeral and can adversely impact fish habitat and water resources infrastructure (e.g. hydropower facilities). Another dynamic process is the formation of ice jams. Ice jams are thick accumulations of broken ice that constrict river flow and thus are often associated with high flood risks. Multi-channel systems such as river deltas and confluences are particularly prone to ice jams. For example, the recent Fort McMurray flood was due to an ice jam formed at the Athabasca-Clearwater River confluence. The complex ways that ice interacts with the flow and river morphology, makes observing and forecasting these dynamic ice events very difficult. There are still many unanswered questions regarding the processes of anchor ice evolution and ice jam forming in multi-channel systems. There is a great need for improving our predictive ability of these dynamic ice events. Climate change makes this even more urgent as the timing, frequency and severity of these ice events are all expected to change. Physics-based numerical models provide powerful forecasting tools, and when used with good laboratory and field data, can also provide great insights into these complex processes. Therefore, I am proposing a research program to address the knowledge gaps related to ice jam and anchor ice processes by developing physics-based modelling methods, conducting laboratory experiments, and/or utilizing field data. The long-term goal is to significantly improve our understanding of, and ability to predict, dynamic ice processes in complex river environments. The short-term objectives are to:     (1)Investigate the dynamic processes occurring in river deltas during ice jamming.     (2)Develop an operational model for predicting flood risk of ice jam prone multi-channel systems.     (3)Determine the meteo-hydrological factors controlling anchor ice formation and release mechanisms.     (4)Assess and improve anchor ice algorithms of existing river ice models. The proposed research program will lead to improved understanding and predictive ability of ice jam and anchor ice events. It will greatly benefit the development and operation of water resources infrastructure and have significant economic value by reducing the adverse impacts of these ice events. It will immediately benefit public safety by providing reliable flood forecasting tool and reducing flood damage. The research will produce an enhanced, physics-based river ice numerical model, which will provide an essential tool to assess the impacts of human activities or climate change on ice regime of northern rivers. This program will also provide high-quality training to a team of graduate and undergraduate students.