Characteristics and evolution of discontinuous permafrost in northern Canada at multiple spatial scales

加拿大北部不连续多年冻土多空间尺度特征及演化

• 批准号: RGPIN-2014-04084
• 负责人: Lewkowicz, Antoni
• 金额: $ 2.19万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=587594
• 关键词: Characteristics; evolution; discontinuous; permafrost; northern

Discontinuous permafrost can be thought of as a patchwork, with seasonally frozen areas and water bodies interfingering with patches of perennially frozen earth materials that vary in size, spatial concentration, thickness, depth to the permafrost table, and thermal regime. Some thin permafrost patches have mean temperatures just a few hundredths of a degree below 0°C, so their thaw due to recent and future climate warming may occur relatively rapidly. Others may take many decades to thaw following climatic warming unless affected simultaneously by changes in drainage. This research program will examine the variation in permafrost distribution and temperature characteristics at micro-, local and regional scales along transects in the Yukon and Labrador, extending from the zone of isolated patches (1-10% of the terrain underlain by permafrost) northward, or upward, to the zone of continuous permafrost (>90% of the terrain underlain by permafrost). The findings will address fundamental questions about the way ground temperature, and hence permafrost distribution, varies along climatic gradients. They will also examine how permafrost distribution changes as the climate warms. The results will assist in better representing discontinuous permafrost in global and regional climate models. In addition, they will be pertinent to predictions of the rate of thaw of permafrost and hence to the potential for positive feedback in the global climate system due to stored carbon release. A combination of field monitoring, geophysical techniques, computer modeling as well as traditional aerial photo interpretation and remote sensing will be used to carry out the research program. The work will involve the training of several graduate students, as well as collaboration with federal government, provincial and territorial-based researchers, and communities. The results are expected to be relevant to assessing the impacts of thawing permafrost on the hydrology and ecology of permafrost regions, as well as helping predict and mitigate the impacts of permafrost degradation on northern infrastructure and resource development.

不连续的永久冻土可以被认为是一个拼凑物，季节性冻结的地区和水体与大小，空间集中度，厚度，永久冻土表的深度和热状况不同的常年冻土材料的补丁相互交织。一些薄的永久冻土块的平均温度仅低于0°C的百分之几度，因此由于最近和未来的气候变暖，它们的融化可能会相对较快。其他地区可能需要几十年才能在气候变暖后解冻，除非同时受到排水变化的影响。 该研究方案将审查沿育空地区和拉布拉多的小尺度、局部尺度和区域尺度的沿着样带的多年冻土分布和温度特征的变化，这些样带从孤立的斑块区（1-10%的地面为多年冻土）向北或向上延伸到连续的多年冻土区（90%以上的地面为多年冻土）。这些发现将解决有关地面温度以及永久冻土分布沿着气候梯度变化的基本问题。他们还将研究永久冻土分布如何随着气候变暖而变化。 研究结果将有助于在全球和区域气候模型中更好地代表不连续的永久冻土。此外，它们将与永冻层融化速率的预测有关，因此也与储存的碳释放在全球气候系统中产生积极反馈的潜力有关。 将采用野外监测、地球物理技术、计算机建模以及传统的航空照片判读和遥感相结合的方法来开展研究计划。这项工作将包括培训几名研究生，以及与联邦政府、省和地区研究人员以及社区合作。预计研究结果将有助于评估冻土融化对冻土区水文和生态的影响，并有助于预测和减轻冻土退化对北方基础设施和资源开发的影响。