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: 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=657400
• 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的地方，季节性冻结的地区和水体与一片片的永久冻结的土壤物质相互交错，这些材料在大小、空间密度、厚度、到永久冻土表的深度和热状况方面都不同。一些薄薄的永久冻土带的平均温度只比0摄氏度低几百分之一度，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地发生。其他的可能需要几十年的时间才能在气候变暖后解冻，除非同时受到排水变化的影响。*这项研究计划将沿着育空和拉布拉多的横断面，从孤立的斑块地带(被永久冻土覆盖的地形的1%-10%)向北或向上延伸到连续永久冻土区(90%的地形被永久冻土覆盖)，在微观、局部和区域尺度上研究永久冻土分布和温度特征的变化。这些发现将解决有关地面温度以及永久冻土分布随气候梯度变化的基本问题。他们还将研究随着气候变暖，永久冻土分布是如何变化的。这些结果将有助于在全球和区域气候模型中更好地表示不连续的永久冻土。此外，它们将与对永久冻土融化速度的预测有关，从而与储存的碳释放在全球气候系统中产生正反馈的潜力有关。*将结合现场监测、地球物理技术、计算机模拟以及传统的航空照片解译和遥感来开展研究计划。这项工作将涉及几名研究生的培训，以及与联邦政府、省和地区研究人员以及社区的合作。预计研究结果将有助于评估多年冻土融化对多年冻土区水文和生态的影响，并有助于预测和减轻多年冻土退化对北方基础设施和资源开发的影响。