Role of radiative forcing on the sea ice melt-growth cycle in a changing Arctic marine environment

不断变化的北极海洋环境中辐射强迫对海冰融化生长循环的作用

• 批准号: 435373-2013
• 负责人: Ehn, Jens
• 金额: $ 2.04万
• 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: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=649955
• 关键词: Role; radiative; forcing; sea; ice

The Arctic sea ice cover is in rapid decline due to global warming with yet another new record low reached in September 2012. The diminishing ice cover is having a discernible impact on the polar marine environment. However, the extent of this impact on future changes to climate, carbon cycling and ecosystems remains uncertain. At the root is how surface radiative forcing affects changes in sea ice properties, and how these changes in turn modulate the forcing. Such interactions form the base of complex climate feedbacks operating in the Arctic. Considering the vastness of the area of sea ice (~10 million km2 or roughly the size of Canada) that forms and then melts each year, the importance of a comprehensive understanding of the processes driving this cycle cannot be overstated.** Given this, the objectives to be addressed in the proposed research are to investigate 1) the reciprocal feedbacks between radiative forcing and the melt evolution of the sea ice surface, 2) how small-scale interactions with the porous sea ice structure and imbedded impurities affect radiative transfer within the sea ice interior, and 3) the importance of variable under-ice radiation fields and optical properties on water column heating and sea ice melt rates.** These three objectives will help answer questions about how sea ice melt is partitioned between surface, interior and bottom, and how much heat is retained in the upper ocean layers where it can cause a delay in the fall freeze-up. Our ability to predict future climate rests on understanding these processes. The objectives are interrelated, yet individually provide suitable and distinct projects for both MSc and PhD studies. This research will advance our knowledge of sea ice processes and climate feedbacks, train new students in Arctic environmental research and ultimately, benefit northerners by improving climate predictions that will help communities and various levels of government adapt to climate change.******

由于全球变暖，北冰洋海冰覆盖率正在迅速下降，2012年9月又创下了新的纪录低点。不断减少的冰盖正在对极地海洋环境产生明显的影响。然而，这种对气候、碳循环和生态系统未来变化的影响程度仍不确定。根本是表面辐射强迫如何影响海冰性质的变化，以及这些变化如何反过来调节强迫。这种相互作用构成了北极复杂气候反馈的基础。考虑到每年形成并随后融化的海冰面积(约1000万平方公里或大致相当于加拿大的大小)，全面了解推动这一循环的过程的重要性怎么强调都不为过。**鉴于此，拟议中的研究目标是调查1)辐射强迫和海冰表面融化演变之间的相互反馈，2)与多孔海冰结构和嵌入的杂质的小规模相互作用如何影响海冰内部的辐射传输，3)可变的冰下辐射场和光学性质对水柱加热和海冰融化速率的重要性。**这三个目标将有助于回答以下问题：海冰融化如何在表面、内部和底部之间分配，以及在可能导致秋季冻结延迟的上层海洋中保留了多少热量。我们预测未来气候的能力取决于对这些过程的理解。这些目标是相互关联的，但各自为硕士和博士研究提供了合适的和不同的项目。这项研究将提高我们对海冰过程和气候反馈的知识，培训北极环境研究的新学生，并最终通过改进气候预测来造福北方人，这将有助于社区和各级政府适应气候变化。