Permafrost thaw: better understanding for better management

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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.**