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

不连续的永久冻土可以被认为是一个拼凑物，季节性冻结区和水体与长年冻土材料的斑块相互交织，这些冻土材料在大小、空间浓度、厚度、永久冻土深度和热状态方面各不相同。一些薄的永久冻土层的平均温度仅比0°C低百分之几，因此它们因近期和未来气候变暖而融化的速度可能相对较快。其他的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。该研究项目将在育空地区和拉布拉多地区沿样带的微观、局部和区域尺度上考察永久冻土分布和温度特征的变化，从孤立的斑块区（永久冻土下地形的1-10%）向北或向上延伸到连续永久冻土区（永久冻土下地形的1- 90%）。这些发现将解决有关地温以及永久冻土分布沿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式中更好地代表不连续的永久冻土。此外，它们将与永久冻土融化速度的预测有关，从而与由于储存的碳释放而在全球气候系统中产生正反馈的可能性有关。将结合现场监测、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来开展研究计划。这项工作将包括对几名研究生的培训，以及与联邦政府、省和地区研究人员以及社区的合作。研究结果将有助于评估冻土融化对冻土地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。

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.