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

尽管北极气候的变暖趋势和相应的永久冻土温度升高有充分的证据，但关于连续永久冻土系统对气候变化的响应仍然存在巨大的不确定性。一些基于模型的研究表明，广泛的地形不稳定、永久冻土融化和消失，而最近基于实地的研究表明，永久冻土系统可能比模拟情景所暗示的更具弹性。关于永久冻土对气候变化的反应的概括可能导致对碳通量、景观变化和基础设施问题的估计出现错误。为了更好地约束模拟活动，迫切需要对活动层和永久冻土上部的热湿通量进行经验观测。

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.