Seasonal decay and break-up of sea ice in the Arctic coastal domain

北极沿海地区海冰的季节性衰退和破裂

• 批准号: RGPIN-2020-05329
• 负责人: Ehn, Jens
• 金额: $ 1.82万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=740513
• 关键词: Seasonal; decay; break; up; sea

The decline of Arctic sea ice is one of the most prominent signals of climate change on Earth. Particularly the thick, multiyear ice is in rapid decline, indicating that the state of the Arctic Ocean is undergoing a shift towards a seasonal sea ice regime with new emerging open water areas. The landfast ice fringing the shores freezes up later, breaks up earlier, and is generally becoming less safe. Coastal communities around the Arctic have raised concern as they depend on the stability of the landfast ice for their subsistence hunting and travel. Less sea ice and more open water allows sunlight to heat the ocean and melt ice more rapidly, resulting in more open water - this is the well-known ice-albedo feedback loop. The Arctic Ocean is also receiving more freshwater from river runoff, glacier meltwater and precipitation. Thus, the Arctic marine environment is becoming both warmer and fresher, and the reduction in sea ice is linked to increased storminess, coastal erosion and permafrost melt. My research involves fieldwork in Arctic coastal communities, in ice camps, or onboard ships to observe and better understand the processes and climate feedbacks that control the seasonal and interannual change of Arctic sea ice. The focus of this research program is on the seasonally sea ice covered coastal and nearshore environment, or the so-called costal domain. The research objectives are to investigate: 1) the interplay between the components of the surface energy balance and the melt progression of the sea ice; 2) how ice melting affects the propagation of sunlight through the sea ice into the water column; and 3) how the seasonal decay and breakup of sea ice in the coastal and nearshore zone has changed over the last decades as a function of thermal decay (i.e., objectives 1 and 2) and external influences from the adjacent terrestrial (warm air advection, impurities, freshwater runoff) and marine domains (oceanic heat, waves, tides, storm surges). With these objectives, I will tackle phenomena that are at the heart of understanding the changing Arctic coastal sea ice environment, which is of particular concern to local residents and land users. Our ability to predict how the marine- and climate system in the Arctic will change, and how ecosystems will respond, rests on understanding the interactions between the sea ice, the ocean and the surrounding terrestrial system. The three objectives of this research program are interrelated, and as such designed as collaborative yet distinct individual projects for 6 PhD, 4 MSc and 5 BSc students. The outcome of this research will advance our knowledge of sea ice processes and climate feedbacks in the new emerging state of the Arctic Ocean, train students in Arctic marine research, involve northern residents in the research, and ultimately, benefit Northerners by improving climate predictions and process understanding that will help communities and various levels of government adapt to climate change.

北冰洋海冰的减少是地球上气候变化最突出的信号之一。尤其是厚厚的多年冰正在迅速减少，这表明北冰洋的状况正在向季节性海冰状况转变，出现了新的开放水域。海岸边缘的陆地冰结冰较晚，破裂较早，总体上变得不那么安全。北极各地的沿海社区提出了担忧，因为他们依赖陆冰的稳定性来维持自己的狩猎和旅行。更少的海冰和更多的开放水域使阳光能够更快地加热海洋并融化冰，从而产生更开放的水域--这就是众所周知的冰-反照率反馈回路。北冰洋还从河流径流、冰川融化和降水中获得更多淡水。因此，北极海洋环境正在变得更加温暖和新鲜，海冰的减少与暴风雨增加、海岸侵蚀和永久冻土融化有关。我的研究涉及到北极沿海社区、冰营或船上的实地工作，以观察和更好地了解控制北冰洋海冰季节性和年际变化的过程和气候反馈。这项研究计划的重点是季节性海冰覆盖的沿海和近岸环境，或所谓的滨海区。研究目的是调查：1)地表能量平衡各组成部分与海冰融化进程之间的相互作用；2)冰融化如何影响阳光透过海冰进入水柱；3)沿海和近岸地区海冰的季节性衰变和破裂是如何在过去几十年中因热衰变(即目标1和2)以及邻近陆地(暖空气平流、杂质、淡水径流)和海洋领域(海洋热、海浪、潮汐、风暴潮)的外部影响而发生变化的。有了这些目标，我将解决一些现象，这些现象是理解不断变化的北极沿海海冰环境的核心，这是当地居民和土地使用者特别关注的问题。我们预测北极的海洋和气候系统将如何变化，以及生态系统将如何响应的能力，取决于了解海冰、海洋和周围陆地系统之间的相互作用。这个研究项目的三个目标是相互关联的，因此被设计成面向6名博士、4名硕士和5名理科学生的协作而又不同的个人项目。这项研究的成果将增进我们对北冰洋这个新出现的国家的海冰过程和气候反馈的了解，培训北极海洋研究方面的学生，让北方居民参与研究，并最终通过改善气候预测和过程理解来造福北方人，这将有助于社区和各级政府适应气候变化。