Author: Marius Balthasar Philipp
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Author: National Research Council
Publisher: National Academies Press
ISBN: 0309301246
Category : Science
Languages : en
Pages : 171

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Permafrost is a thermal condition-its formation, persistence and disappearance are highly dependent on climate. General circulation models predict that, for a doubling of atmospheric concentrations of carbon dioxide, mean annual air temperatures may rise up to several degrees over much of the Arctic. In the discontinuous permafrost region, where ground temperatures are within 1-2 degrees of thawing, permafrost will likely ultimately disappear as a result of ground thermal changes associated with global climate warming. Where ground ice contents are high, permafrost degradation will have associated physical impacts. Permafrost thaw stands to have wide-ranging impacts, such as the draining and drying of the tundra, erosion of riverbanks and coastline, and destabilization of infrastructure (roads, airports, buildings, etc.), and including potential implications for ecosystems and the carbon cycle in the high latitudes. Opportunities to Use Remote Sensing in Understanding Permafrost and Related Ecological Characteristics is the summary of a workshop convened by the National Research Council to explore opportunities for using remote sensing to advance our understanding of permafrost status and trends and the impacts of permafrost change, especially on ecosystems and the carbon cycle in the high latitudes. The workshop brought together experts from the remote sensing community with permafrost and ecosystem scientists. The workshop discussions articulated gaps in current understanding and potential opportunities to harness remote sensing techniques to better understand permafrost, permafrost change, and implications for ecosystems in permafrost areas. This report addresses questions such as how remote sensing might be used in innovative ways, how it might enhance our ability to document long-term trends, and whether it is possible to integrate remote sensing products with the ground-based observations and assimilate them into advanced Arctic system models. Additionally, the report considers the expectations of the quality and spatial and temporal resolution possible through such approaches, and the prototype sensors that are available that could be used for detailed ground calibration of permafrost/high latitude carbon cycle studies.

Author: Intergovernmental Panel on Climate Change (IPCC)
Publisher: Cambridge University Press
ISBN: 9781009157971
Category : Science
Languages : en
Pages : 755

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Book Description
The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for assessing the science related to climate change. It provides policymakers with regular assessments of the scientific basis of human-induced climate change, its impacts and future risks, and options for adaptation and mitigation. This IPCC Special Report on the Ocean and Cryosphere in a Changing Climate is the most comprehensive and up-to-date assessment of the observed and projected changes to the ocean and cryosphere and their associated impacts and risks, with a focus on resilience, risk management response options, and adaptation measures, considering both their potential and limitations. It brings together knowledge on physical and biogeochemical changes, the interplay with ecosystem changes, and the implications for human communities. It serves policymakers, decision makers, stakeholders, and all interested parties with unbiased, up-to-date, policy-relevant information. This title is also available as Open Access on Cambridge Core.

Author: Daqing Yang
Publisher: Springer Nature
ISBN: 3030509303
Category : Science
Languages : en
Pages : 914

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This book provides a comprehensive, up-to-date assessment of the key terrestrial components of the Arctic system, i.e., its hydrology, permafrost, and ecology, drawing on the latest research results from across the circumpolar regions. The Arctic is an integrated system, the elements of which are closely linked by the atmosphere, ocean, and land. Using an integrated system approach, the book’s 30 chapters, written by a diverse team of leading scholars, carefully examine Arctic climate variability/change, large river hydrology, lakes and wetlands, snow cover and ice processes, permafrost characteristics, vegetation/landscape changes, and the future trajectory of Arctic system evolution. The discussions cover the fundamental features of and processes in the Arctic system, with a special focus on critical knowledge gaps, i.e., the interactions and feedbacks between water, permafrost, and ecosystem, such as snow pack and permafrost changes and their impacts on basin hydrology and ecology, river flow, geochemistry, and energy fluxes to the Arctic Ocean, and the structure and function of the Arctic ecosystem in response to past/future changes in climate, hydrology, and permafrost conditions. Given its scope, the book offers a valuable resource for researchers, graduate students, environmentalists, managers, and administrators who are concerned with the northern environment and resources.

Author: Min Liew
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Degradation and erosion of permafrost have induced irreversible damage to civil infrastructure across the Arctic. These unprecedented changes are now threatening indigenous Arctic communities, urging them to consider community-wide relocations. It is therefore important to understand the geotechnical implications of permafrost affected by the changing climate. In this dissertation, a comprehensive research framework is developed to understand the effects of permafrost degradation and permafrost coastal erosion and their potential impacts on civil infrastructure in the Arctic. This dissertation aims to facilitate a physics-informed, culturally relevant, and inclusive infrastructure planning process for the Arctic community by bridging the experience of indigenous Arctic communities and the expertise of multidisciplinary scientific communities. A community survey is first designed and conducted to understand the effects of permafrost degradation and coastal erosion on civil infrastructure. Observations were collected from residents in four Arctic coastal communities: Point Lay, Wainwright, Utqiaġvik, and Kaktovik. The types, locations, and periods of observed permafrost thaw and coastal erosion were elicited. Survey participants also reported the types of civil infrastructure being affected by permafrost degradation and coastal erosion and any damage to residential buildings. This study shows a useful approach to coproduce knowledge with Arctic residents to identify locations of permafrost thaw and coastal erosion at higher spatial resolution as well as the types of infrastructure damage of most concern to Arctic residents. Then, the state-of-practice of coastal erosion control measures in permafrost regions are synthesized. The study shows the challenges in constructing the current erosion control measures and the escalating cost of the measures over the last four decades. Emerging solutions and research gaps are also identified and discussed so that these measures may be upscaled for full-scale applications in the future. In this dissertation, the physical processes of permafrost degradation are synthesized and presented in a geotechnical context. Geophysical and geomechanical properties of permafrost that are critical for the assessment of foundation performance under permafrost degradation are identified, collected, and analyzed. While the data collected are highly scattered, regression analysis shows that most of the geomechanical and geophysical properties have strong associations with temperature. These associations highlight that the ongoing warming can greatly affect the performance of civil infrastructures in the Arctic. Finally, a three-dimensional fully coupled thermo-hydro-mechanical (THM) model is developed to simulate permafrost degradation. Physical processes such as heat conduction, phase change, thermal convection, fluid flow due to pore water pressure, elevation, and thermal gradient, and force equilibrium based on effective stress theory are considered in this model. The THM model is validated using thaw settlement results from the literature. A parametric study is also conducted to investigate the influences of various input parameters on the thermo-hydro-mechanical behaviors of permafrost with temperature.

Author: Benjamin M. Jones
Publisher: Frontiers Media SA
ISBN: 2889760243
Category : Science
Languages : en
Pages : 255

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Author: National Academies of Sciences, Engineering, and Medicine
Publisher: National Academies Press
ISBN: 0309492432
Category : Science
Languages : en
Pages : 29

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We live on a dynamic Earth shaped by both natural processes and the impacts of humans on their environment. It is in our collective interest to observe and understand our planet, and to predict future behavior to the extent possible, in order to effectively manage resources, successfully respond to threats from natural and human-induced environmental change, and capitalize on the opportunities â€" social, economic, security, and more â€" that such knowledge can bring. By continuously monitoring and exploring Earth, developing a deep understanding of its evolving behavior, and characterizing the processes that shape and reshape the environment in which we live, we not only advance knowledge and basic discovery about our planet, but we further develop the foundation upon which benefits to society are built. Thriving on Our Changing Planet: A Decadal Strategy for Earth Observation from Space (National Academies Press, 2018) provides detailed guidance on how relevant federal agencies can ensure that the United States receives the maximum benefit from its investments in Earth observations from space, while operating within realistic cost constraints. This short booklet, designed to be accessible to the general public, provides a summary of the key ideas and recommendations from the full decadal survey report.

Author: Roger John Michaelides
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Air temperatures in the Arctic are increasing at twice the global rate, making permafrost regions one of the most vulnerable ecosystems in a changing climate [Jorgenson et al., 2001]. Permafrost, or ground that remains frozen for two or more consecutive years, covers 24% of the Northern Hemisphere and contains 60% of the world's soil carbon [Turetsky et al., 2019a]. Large stores of soil carbon are bound in permafrost, predominantly as carbon dioxide (CO2) and methane (CH4); this bound soil carbon is susceptible to rapid decomposition and release into the atmosphere after thaw [Natali et al., 2019]. As air temperatures rise, permafrost regions experience i) seasonal thawing and freezing, and ii) permanent thaw and loss of frozen ground. These processes modify ecosystems, change land cover and surface hydrologic regimes, and release vast amounts of greenhouse gases into the atmosphere. Due to the amount of permafrost soil carbon susceptible to release into the atmosphere, there is a critical need to monitor permafrost status and vulnerability to change, as well as project future behavior of the permafrost system. The vast spatial extent of permafrost regions and their inaccessibility provides challenges to monitoring efforts. In situ methods of characterizing permafrost processes are spatially sparse, restricting regional studies of permafrost thaw status, and introducing uncertainties into climate models. Remote-sensing techniques are an attractive method for characterizing and monitoring permafrost systems on large scales. Interferometric Synthetic Aperture Radar (InSAR) is a geodetic technique for measuring temporal variations of the surface of the Earth, in which repeated synthetic aperture radar (SAR) images are acquired over a region of interest. These images are then interferometrically combined, and the resulting phase difference between SAR images quantifies surface topography and deformation of the surface of the Earth. InSAR, with its fine spatial resolution and broad coverage, presents an attractive method for regional characterization of permafrost thaw status and active layer thickness at fine resolution. However, in permafrost regions, variations in soil moisture, vegetation, snow cover, and phase changes of pore-bound water and ice all affect the observed deformation and can amplify signal decorrelation. This decorrelation can complicate, and in severe cases preclude, the estimation of surface deformation from InSAR phase observations. In this dissertation, we use the InSAR technique to observe permafrost processes in the discontinuous permafrost zone, with a case study in the Izaviknek Highlands region of the Yukon-Kuskokwim delta in Southwestern Alaska. We measure both centimetric seasonal deformation of permafrost associated with seasonal freeze/thaw processes, as well as long-term, interannual deformation associated with permafrost thaw and degradation. We find significant long-term deformation on the order of centimeters per year associated with a complex of wildfire burns in this region, which we relate to the age of wildfire events, and demonstrate that InSAR successfully captures permafrost dynamics induced by wildfire decades after the original burn. We also introduce a method of quantifying and removing decorrelation phase artifacts from InSAR observations by exploiting closure phase relations within a subset of SAR scenes. We show that decorrelation phase biases on the order of tens of degrees can be successfully characterized and re- moved from the original InSAR signal. Further, we investigate the impact of variable soil moisture on closure phase observations using a new SAR interferometric imaging model that explicitly accounts for signal decorrelation treating scattering surfaces as realizations of stochastic processes. Finally, we construct an algorithm that combines the SAR interferometric imaging model introduced above with direct closure phase observations to estimate changes in surface soil moisture state directly from InSAR phase measurements.

Author: Ernest de Koven Leffingwell
Publisher:
ISBN:
Category : Alaska
Languages : en
Pages : 312

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Author: National Research Council
Publisher: National Academies Press
ISBN: 0309301866
Category : Science
Languages : en
Pages : 240

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Once ice-bound, difficult to access, and largely ignored by the rest of the world, the Arctic is now front and center in the midst of many important questions facing the world today. Our daily weather, what we eat, and coastal flooding are all interconnected with the future of the Arctic. The year 2012 was an astounding year for Arctic change. The summer sea ice volume smashed previous records, losing approximately 75 percent of its value since 1980 and half of its areal coverage. Multiple records were also broken when 97 percent of Greenland's surface experienced melt conditions in 2012, the largest melt extent in the satellite era. Receding ice caps in Arctic Canada are now exposing land surfaces that have been continuously ice covered for more than 40,000 years. What happens in the Arctic has far-reaching implications around the world. Loss of snow and ice exacerbates climate change and is the largest contributor to expected global sea level rise during the next century. Ten percent of the world's fish catches comes from Arctic and sub-Arctic waters. The U.S. Geological Survey estimated that up to 13 percent of the world's remaining oil reserves are in the Arctic. The geologic history of the Arctic may hold vital clues about massive volcanic eruptions and the consequent release of massive amount of coal fly ash that is thought to have caused mass extinctions in the distant past. How will these changes affect the rest of Earth? What research should we invest in to best understand this previously hidden land, manage impacts of change on Arctic communities, and cooperate with researchers from other nations? The Arctic in the Anthropocene reviews research questions previously identified by Arctic researchers, and then highlights the new questions that have emerged in the wake of and expectation of further rapid Arctic change, as well as new capabilities to address them. This report is meant to guide future directions in U.S. Arctic research so that research is targeted on critical scientific and societal questions and conducted as effectively as possible. The Arctic in the Anthropocene identifies both a disciplinary and a cross-cutting research strategy for the next 10 to 20 years, and evaluates infrastructure needs and collaboration opportunities. The climate, biology, and society in the Arctic are changing in rapid, complex, and interactive ways. Understanding the Arctic system has never been more critical; thus, Arctic research has never been more important. This report will be a resource for institutions, funders, policy makers, and students. Written in an engaging style, The Arctic in the Anthropocene paints a picture of one of the last unknown places on this planet, and communicates the excitement and importance of the discoveries and challenges that lie ahead.