Permafrost degradation mechanisms in organic-covered terrains and linkages to runoff production

近年来，前所未有的变暖和人类干扰导致有机物覆盖的永久冻土地带的永久冻土大量退化，包括覆盖加拿大北部大片地区的北极和高山苔原、针叶林和北方地区。对永久冻土退化的机制和速度以及永久冻土退化对排水和蓄水模式及过程的影响仍然缺乏了解。因此，多年冻土融化过程中的径流动态预测是寒区水文学研究的一个重要课题。这突出表明，需要进行健全的科学研究，为北方水资源的知情和可持续管理提供知识。这项研究的目的是产生这些知识，并从它产生一套新的模型，用于预测多年冻土对气候变暖和人类干扰的响应，使流域径流可以更有信心地预测在融化的多年冻土的背景下。短期目标是：（1）记录研究区上半个世纪来冻土分布的变化;（2）建立关键水文过程的概念和数学模型，包括图尺度流量和主要地形类型之间的流量;（3）检查冻土对覆盖树冠变化的响应;（4）确定控制可能导致冻土退化的优先融化速率和模式的关键因素;（5）建立一个新的模型，模拟冻土对气候变暖和人为干扰的连续和不连续响应;将水文模型与冻土模型耦合，预测冻土的空间分布，以及气候变暖和人为干扰情景下的河流水流状况。这项研究将在西北地区斯科蒂溪的湿地主导的不连续永久冻土区进行，因为它有丰富的数据档案，基础设施和设备的高度集中，以及当地社区的兴趣和支持。广泛的成本分摊和数据共享机会与正在进行的免费研究项目也使斯科蒂溪一个合乎逻辑的研究网站。然而，该项目的结果是打算转移到其他广泛存在的有机覆盖的永久冻土地形类型。

Unprecedented warming and human disturbance has led to substantial permafrost degradation in recent years in organic-covered permafrost terrains, including the arctic and alpine tundra, taiga and boreal regions that characterise vast areas of Canada's north. There remains a lack of understanding of the mechanisms and rates of permafrost degradation, and the influence of the latter on water drainage and storage patterns and processes. As a result, a major challenge of cold regions hydrology lies in predicting runoff dynamically with permafrost thaw. This underscores the need for sound scientific research to provide the knowledge for informed and sustainable management of northern water resources. This research aims to generate this knowledge, and from it produce a new suite of models for predicting the response of permafrost to climate warming and human disturbance so that basin runoff can be more confidently predicted in the context of thawing permafrost. The short-term objectives are: 1) document the change in permafrost distribution over the last half century at the study site; 2) develop conceptual and mathematical models of key hydrological processes, including plot-scale flows and flows among the major terrain types; 3) examine the permafrost response to changes in the overlying tree canopy; 4) identify the key factors controlling the rates and patterns of preferential thaw that may lead to permafrost degradation; 5) develop a new model that simulates the discontinuous and continuous permafrost response to climate warming and human disturbance; and 6) couple the hydrological and permafrost models to predict the spatial distribution of permafrost, and the river flow regime under scenarios of climate warming and human disturbance. The study will be conducted in the wetland-dominated zone of discontinuous permafrost at Scotty Creek, NWT, because of its rich data archive, high concentration of infrastructure and equipment, and local community interest and support. Extensive cost-sharing and data-sharing opportunities with on-going complimentary research projects also make Scotty Creek a logical study site. However, the project results are intended to be transferable to other widely-occurring organic-covered permafrost terrain types.