Physics of seasonal sea ice (PSI)

人们早就知道，表面重力波可以在海冰覆盖范围内传播很远的距离，并有助于将其分解成更小的碎片，称为浮冰。在我们观察到的北极海冰迅速变化的背景下，随着时间的延长，海冰的能量和动量增加，海冰变薄，海浪发挥着越来越重要的作用。然而，无论是用于气候研究还是业务大洋预报的数值模型中，都几乎没有考虑到海浪与冰的相互作用。有许多涉及海浪和海冰的潜在反馈过程，如果没有在数值模式中充分表示相关的物理机制，这些过程的影响是困难的。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适应的新数据集。尽管在海冰和海浪的卫星遥感方面已经取得了巨大的进展，但时间频率和空间分辨率还不够高，无法分辨相关的尺度。在波浪水槽中进行的实验室实验结果是有用的，但它们对自然环境的适用性仍然有限。拟议中的计划的目标是显著提高我们对波浪-冰相互作用的理解和模型，这些相互作用在很大程度上控制着季节性海冰。特别是，拟议的研究将集中在1)碎屑动力学，2)厚度和浮冰大小分布的演变，3)边缘冰区的波能和动量平衡，4)波浪和浮冰大小对海冰流变性的影响。所提出的方法遵循迭代假设驱动的方法，具有两个同等重要和协同的组成部分。第一部分是每年冬季在季节性结冰的圣劳伦斯河口进行的一系列实地实验。与冰上独木舟一起部署在冰面上的延时相机、无人机、系泊设备和其他仪器将提供前所未有的完整性数据集。观测将为波浪-冰相互作用的参数化的发展提供信息，这些参数将在不同的模型配置中进行测试，具有不同的真实感水平。最终，在数值模式中表示波-冰耦合过程有可能显著提高短期业务预报、季节和长期气候预测的性能。这项提议的一个长期目标是在加拿大提供第一个完全耦合的大气-冰-海浪作业预报系统，该系统可有效地用于极地和亚极地海洋环境中作业的安全规划。

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.