Physics of seasonal sea ice (PSI)

众所周知，表面重力波可以在海冰盖内传播很长的距离，并导致海冰破碎成更小的碎片，称为浮冰。在我们观察到的北极海冰快速变化的背景下，波浪发挥着越来越重要的作用，因为更长的距离增加了波浪的能量和动量，而海冰变得越来越薄。然而，波冰相互作用几乎没有包含在用于气候研究或业务气象海洋预报的数值模型中。有许多涉及波浪和海冰的潜在反馈过程，如果没有在数值模型中充分表示相关物理机制，其影响是很困难的。然而，为了在模型方面取得进展，人们认识到需要与我们想要理解和建模的过程相匹配的新数据集。尽管海冰和波浪的卫星遥感已经取得并尚未取得巨大进展，但时间频率和空间分辨率还不够高，无法解析相关尺度。在波浪池中进行的实验室实验获得的结果是有用的，但它们对自然环境的适用性仍然有限。拟议计划的目标是显着推进我们对波冰相互作用的理解和模型，波冰相互作用在很大程度上控制季节性海冰。特别是，拟议的研究将集中在i）冰晶动力学，ii）厚度和浮冰尺寸分布的演变，iii）边缘冰区的波浪能量和动量平衡以及iv）波浪和浮冰尺寸对海冰流变学的影响。所提出的方法遵循迭代假设驱动的方法，具有两个同等重要且协同的组成部分。第一个组成部分是每年冬季在季节性冰雪覆盖的圣劳伦斯河口进行一系列现场实验。随冰独木舟部署在冰上的延时摄影机、无人机、系泊装置和其他仪器将提供前所未有的完整数据集。观测结果将为波冰相互作用参数化的开发提供信息，以便在具有不同真实程度的各种模型配置中进行测试。最终，在数值模型中表示耦合的波冰过程有可能显着提高短期业务预测、季节性和长期气候预测的性能。该提案的长期目标是在加拿大提供第一个完全耦合的大气-冰-海洋波业务预报系统，该系统可有效用于极地和次极地海洋环境中业务的安全规划。

It is long known that surface gravity waves can propagate significant distances within the sea ice cover and contribute to its break-up into smaller pieces called floes. In the context of the rapid changes that we observe in Arctic sea ice, waves play an increasingly important role as longer fetch increase their energy and momentum and sea ice gets thinner. Yet, wave-ice interactions are barely included in numerical models used either for climate studies or operational met-ocean forecasting. There are numerous potential feedback processes involving waves and sea ice, the impact of which is difficult without adequate representation of the relevant physical mechanisms in numerical models. In order to make progress with models, however, there is a recognized need for new datasets that are commensurate with processes we want to understand and model. Despite the enormous progress realized and yet to come in satellite remote sensing of sea ice and waves, the temporal frequency and the spatial resolution isn't high enough to resolve the relevant scales. Results obtained form laboratory experiments performed in wave tanks are useful, but their applicability to natural environments remains limited. The proposed program's goal is to significantly advance our understanding and models of wave-ice interactions that heavily control seasonal sea ice. In particular, the proposed research will focus on i) frazil dynamics, ii) the evolution of the thickness and floe size distribution, iii) the wave energy and momentum balance in the marginal ice zone and iv) the influence of waves and floe size on sea ice rheology. The proposed methodology follows an iterative hypothesis-driven approach with two equally important and synergistic components. The first component is a series of field experiments to be carried annually during winter in the seasonally ice-covered St. Lawrence Estuary. Time-lapse cameras, drones, moorings and other instruments deployed on the ice with an ice canoe will provide datasets of unprecedented completeness. Observations will inform the development of parameterizations of wave-ice interactions to be tested in various model configurations, with different levels of realism. Ultimately, representing coupled wave-ice processes in numerical models has the potential to significantly increase the performance of short-term operational forecasting, seasonal and long-term climate projections. A long-term goal of this proposal is to deliver, in Canada, the first fully coupled atmosphere-ice-ocean-wave operational forecasting system that is effectively used for the safe planning of operations in polar and subpolar marine environments.