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称为浮冰的较小碎片。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，因为更长的风吹增加了它们的能量和动量，海冰变得越来越薄。然而，波冰相互作用几乎没有包括在用于气候研究或业务Met-Ocean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，如果在数值模型中没有充分表示相关的物理机制，就很难了解其影响。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称的新数据集。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，无法分辨相关尺度。从波浪水槽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。该计划的目标是显着推进我们对波浪-冰相互作用的理解和模型，这些相互作用严重控制着季节性海冰。特别是，拟议的研究将集中在i）frazil动力学，ii）厚度和浮冰大小分布的演变，iii）在边缘冰区的波能和动量平衡和iv）波浪和浮冰大小对海冰流变学的影响。拟议的方法遵循一个迭代的假设驱动的方法，两个同样重要和协同作用的组成部分。第一个组成部分是一系列的现场实验，每年冬季在季节性冰覆盖的圣劳伦斯河口进行。延时摄影机、无人机、系泊设备和其他用冰独木舟部署在冰上的仪器将提供前所未有的完整数据集。观测将为波冰相互作用参数化的发展提供信息，这些参数化将在不同的模型配置中进行测试，具有不同的现实水平。最后，在数值模型中表示波冰耦合过程有可能大大提高短期业务预报、季节性和长期气候预测的性能。这项建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-海浪业务预报系统，有效地用于极地和次极地海洋环境中的业务安全规划。

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.