Permafrost thaw: better understanding for better management

简介：永久冻土带存在于加拿大陆地面积的30-50%以下，其中越来越多的永久冻土带正在进入解冻状态（地下冰的缓慢损失），在大多数地区将持续数十年至数百年。该计划旨在通过提供新的见解、技术、方法和HQP来加强量化永久冻土融化的能力。这是及时的，因为温度，今天用来测量和描述永久冻土状态的主要量，本身不太适合在一个由实际或即将融化主导的环境中为决策和研究提供信息。***预期结果：该计划将产生一种新的测量方法，通过观察地下冰和水含量的变化，以及下一代计算机模拟工具和方法，将大气和地表的变化与永久冻土融化联系起来，从而量化永久冻土融化。这些能力有望更好地了解永久冻土融化过程及其在空间和时间上的自然变化，并直接转化为应用。******方法：该计划是建立在计算机模拟和永久冻土融化的实地测量的联合解释。为了在有关尺度上提供有关变量的数据，正在调整和发展若干测量方法。基于原位介电特性的测量，采用了一种原型传感器来定量测量地面冰和液态水的含量。重复地面激光扫描用于提供102至103平方米面积的精确表面积分，其差异用冰损失来解释。对于这些地区，为了参数化模拟，还在野外量化了地表和地下物质以及地形和植被的非均质性。温度和冰含量的变化是基于将大气再分析与地面测量联系起来的模拟框架计算的。意义：通过阐明地下冰和水动力学，本项目将为永久冻土科学提供关键贡献。在其对陆地生态系统、工程和气候变化影响的快速发展的研究中，更严格和正式的量化解冻将具有广泛的意义。该计划进一步为改善快速环境变化的管理提供了一个关键因素：基于工程或环境变化建立情景的能力（技术和HQP形式），并区分可能和不可能的未来状态。潜在用户包括设计、建造或运营基础设施的行业，以及运营基础设施或关注永久冻土区自然保护和环境监测的政府机构

INTRODUCTION: Permafrost is present beneath 30-50% of Canada's land area and more and more of this is entering a state of thaw (slow loss of subsurface ice) that in most parts will persist for decades to centuries. This program aims to strengthen the ability to quantify thawing permafrost by providing new insight, technology, methods, and HQP. This is timely because temperature, the main quantity used for measuring and describing the state of permafrost today, is by itself not well suited to inform decisions and research in an environment dominated by actual or impending thaw.***EXPECTED RESULTS: This program will result in a new class of measurements to quantify permafrost thaw by observing changes in the subsurface contents of ice and water as well as next generation computer simulation tools and methods linking changes in the atmosphere and at the ground surface with permafrost thaw. These capabilities are expected to provide better insight into the processes of permafrost thaw and their natural variability in space and time and to directly translate to application. ******METHODS: The program is built around the joint interpretation of computer simulations and field measurements of permafrost thaw. To provide data of relevant variables at relevant scales, a number of measurement methods are being adapted and developed. A prototype sensor is used to quantify ice and liquid water contents in the ground based on measuring in situ dielectric characteristics. Repeated terrestrial laser scanning is used to provide accurate surface integrals for areas of 102 to 103 m2, the difference of which is interpreted in terms of ice loss. For these areas, also the heterogeneity of surface and subsurface material as well as topography and vegetation are quantified in the field in order to parameterize simulations. Changes in temperature and ice content are computed based on a simulation framework linking atmospheric re-analyses with ground measurements.***SIGNIFICANCE: By elucidating subsurface ice and water dynamics this project will provide a key contribution to permafrost science. In the rapidly growing research on its effects on terrestrial ecosystems, engineering, and climate change, a more rigorous and formal quantification of thaw will be of broad significance. This program further contributes a key element to the improved management of rapid environmental change: The ability (technical and in the form of HQP) to build scenarios based on engineering or environmental change and to distinguish likely from unlikely future states. Potential users include industry that designs, builds, or operates infrastructure as well as government agencies operating infrastructure or concerned with nature protection and environmental monitoring in permafrost areas.**