Evaluating and predicting the resiliency of lakes

湖泊正在因人类活动而发生变化。评估和预测湖泊对这些变化的恢复力对于制定缓解和管理战略至关重要。拟议的研究计划旨在开发诊断和预测工具，以评估湖泊对气候变化中人类影响的反应。该研究计划将侧重于湖泊物理输运过程，包括内波，冰下环流，以及热分层的季节和年际演变。与研究伙伴合作，这将扩大到评估和预测水质和生态影响，湖泊生态和水质取决于从湍流到年际的时间尺度和从个体生物到流域大小的空间尺度上的物理过程。取决于当地气候，热分层的季节性演变的典型特征是由短暂的完全混合期（几天到几周）分隔的长期（几个月）热分层。在加拿大的气候中，所有这些过程都是由雪和冰覆盖所介导的。每个湖泊的生态都适应并依赖于这些季节性混合事件的时间和频率，以及积雪和冰盖的持续时间和质量。然而，气候变化的影响，有时再加上直接的人为干预（通过连续排放或快速倾倒增加物质和能量），可能会大大改变混合、分层和冰雪覆盖期的时间和持续时间，这可能对居民生态和水质产生严重影响。拟议的研究将实地测量与数值水动力学建模相结合，以评估和预测湖泊弹性。在这方面，实地和数值方法为实地数据提供了重要的补充，实地数据在描述湖泊系统如何运作方面提供了“基本事实”，以及验证数值模型所需的基本数据，这些数据可用于：1）量化质量输运，2）过程研究（隔离关键过程），以及3）预测人类活动（意外或管理）和/或气候变暖的未来影响。拟议研究的最终结果将是更好地了解有冰和无冰湖泊和水库的环流和运输动力学，以及这些湖泊和水库的数值水动力学模型的开发和应用。从目标湖泊的结果将被推广，以提高数值流体动力学，水质和生态建模能力。

Lakes are changing in response to human activity. Evaluating and predicting lake resiliency to these changes is crucial to developing mitigation and management strategies. The proposed research program aims to develop diagnostic and prognostic tools to assess a lake's response to human impacts within a changing climate. The proposed research program will focus on lacustrine physical transport processes including internal waves, under-ice circulation, and seasonal and inter-annual evolution of thermal stratification. This, in collaboration with research partners will be extended to assess and predict water quality and ecological impacts.Lake ecology and hence water quality is dependent on physical processes at time scales ranging from turbulence to inter-annual, and spatial scales from individual organism to basin size. Depending on local climate, the seasonal evolution of thermal stratification is typically characterized by prolonged (months) thermal stratification separated by brief periods of complete mixing (days to weeks). In a Canadian climate all of these processes are mediated by snow and ice-cover. Each lake's ecology is adapted to and dependent on the timing and frequency of these seasonal mixing events, as well as duration and quality of snow and ice-cover. However, impacts of a changing climate, sometimes combined with direct human intervention (addition of material and energy through continuous discharge or rapid dumping), can drastically change the timing and duration of mixing, stratification, and snow/ice cover periods, which can have dire implications for resident ecology and water quality. The proposed research combines field measurements with numerical hydrodynamic modelling to evaluate and predict lake resiliency. In this regard, field and numerical methods provide an important complement to field data that provides "ground truth" in describing how a lake system functions, as well as essential data needed to validate numerical models, which can be used for 1) quantifying mass transport, 2) process studies (isolating critical processes), and 3) predicting the future impact of human activities (accidental or managed) and/or climate warming. The end result of the proposed research will be an improved understanding of the circulation and transport dynamics of ice-covered and ice-free lakes and reservoirs, as well as development and application of numerical hydrodynamic models of these lakes and reservoirs. Results from targeted lakes will be generalized to enhance numerical hydrodynamic, water quality and ecological modelling capabilities.