Vulnerability and resiliency of continuous permafrost in a changing climate: Thresholds of non-recoverable change.

气候变化中连续永久冻土的脆弱性和恢复力：不可恢复变化的阈值。

• 批准号: RGPIN-2017-04030
• 负责人: Pollard, Wayne
• 金额: $ 2.84万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=687466
• 关键词: Vulnerability; resiliency; continuous; permafrost; changing

Despite the well-documented warming trend in Arctic climate and a corresponding increase in permafrost temperatures there remains tremendous uncertainty about the response of continuous permafrost systems to climate change. Several model-based studies suggest widespread terrain instability, melting and disappearance of permafrost, while recent field-based studies indicate that permafrost systems may be more resilient than modelling scenarios imply. Generalizations concerning permafrost response to climate change can result in errors in estimates of carbon flux, landscape change and infrastructure problems. There is an urgent need for empirical observation of heat and moisture fluxes for the active layer and the upper part of permafrost to better constrain modeling activities. ***The primary goal of this research is to assess the vulnerability of key high Arctic permafrost systems to climate change by focusing on thermodynamic processes in the active layer and at the active layer permafrost interface. ******Field sites on Ellesmere and Axel Heiberg Islands will include areas characterized by ice wedge systems, wetlands, and tundra landscapes underlain by ground ice. ******Methods By making detailed measurements of boundary layer climate, surface temperature, temperatures, and mass and energy fluxes through the active layer and at the permafrost table coupled with observations on seasonal snow depth and distribution, vegetation, and local topographic changes for specific geo-ecosystems this research will contribute a better understanding about the dynamic relationship between climate inputs and permafrost response. By looking at permafrost as a complex adaptive system this study will identify various feedback processes that contribute to system resiliency and potential tipping points. It is well understood that once widespread thermokarst begins permafrost systems become highly unstable and the normal self regulating processes often require decades to re-establish a new equilibrium. By coupling measurements of CO2 and CH4 flux to these observations this study not only defines the thresholds of change but potential feedbacks to the climate system. ******Applied research This study will assess the potential impact of changing active layer conditions on contaminated soils. There are many sites throughout the high Arctic of past and present fuel storage in steel drums that are notorious for leaking and fuel transfer processes that lead to spills. This study will assess the extent of residual contamination and potential remobilization of contaminants under scenarios of increased active layer depth and melting ground ice. This research involves the use of a wide range in research tools; in addition to site specific monitoring systems and subsurface mapping tools like GPR and Resistivity this research will use an unmanned aerial vehicle (UAV) to map small scale changes and identify thaw hotspots.

尽管北极气候中有充分记录的变暖趋势和多年冻土温度的相应升高，但连续多年冻土系统对气候变化的响应仍然存在极大的不确定性。一些基于模型的研究表明，永久冻土的广泛地形不稳定性，熔化和消失，而最近的基于现场的研究表明，多年冻土系统可能比建模场景暗示的更具弹性。关于对气候变化的多年冻土反应的概括会导致碳通量，景观变化和基础设施问题的估计错误。迫切需要对活性层的热量和水分通量进行经验观察，以便更好地约束建模活动。 ***这项研究的主要目的是通过关注活动层中的热力学过程和在活性层永久冻土界面中，评估关键高北极冻土系统与气候变化的脆弱性。 ****** Ellesmere和Axel Heiberg群岛上的现场将包括以冰楔系统，湿地和苔原景观为特征的区域，并由地面冰覆盖。 ******Methods By making detailed measurements of boundary layer climate, surface temperature, temperatures, and mass and energy fluxes through the active layer and at the permafrost table coupled with observations on seasonal snow depth and distribution, vegetation, and local topographic changes for specific geo-ecosystems this research will contribute a better understanding about the dynamic relationship between climate inputs and permafrost response.通过将永久冻土视为一种复杂的自适应系统，该研究将确定各种有助于系统弹性和潜在倾斜点的反馈过程。众所周知，一旦广泛的Thermokarst开始永久冻土系统变得高度不稳定，并且正常的自我调节过程通常需要数十年才能重新建立新的平衡。通过将CO2和CH4通量的测量与这些观察结果耦合，本研究不仅定义了变化的阈值，而且定义了对气候系统的潜在反馈。 ******应用研究本研究将评估改变活动层条件对受污染土壤的潜在影响。在过去和现在的燃油存储中，有许多地点在钢鼓中存储，这些燃油存储因泄漏和燃油传输过程而导致溢出物而臭名昭著。这项研究将评估在活动层深度增加和熔化地面冰的情况下，污染物的残留污染程度和潜在的污染物重新化程度。这项研究涉及在研究工具中使用广泛的范围。除了特定于现场监控系统和地下映射工具之外，此研究还将使用无人机（UAV）来绘制小规模更改并识别融化热点。