92,685 research outputs found

    Arctic in Rapid Transition (ART) : science plan

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    The Arctic is undergoing rapid transformations that have brought the Arctic Ocean to the top of international political agendas. Predicting future conditions of the Arctic Ocean system requires scientific knowledge of its present status as well as a process-based understanding of the mechanisms of change. The Arctic in Rapid Transition (ART) initiative is an integrative, international, interdisciplinary pan-Arctic program to study changes and feedbacks among the physical and biogeochemical components of the Arctic Ocean and their ultimate impacts on biological productivity. The goal of ART is to develop priorities for Arctic marine science over the next decade. Three overarching questions form the basis of the ART science plan: (1) How were past transitions in sea ice connected to energy flows, elemental cycling, biological diversity and productivity, and how do these compare to present and projected shifts? (2) How will biogeochemical cycling respond to transitions in terrestrial, gateway and shelf-to-basin fluxes? (3) How do Arctic Ocean organisms and ecosystems respond to environmental transitions including temperature, stratification, ice conditions, and pH? The integrated approach developed to answer the ART key scientific questions comprises: (a) process studies and observations to reveal mechanisms, (b) the establishment of links to existing monitoring programs, (c) the evaluation of geological records to extend time-series, and (d) the improvement of our modeling capabilities of climate-induced transitions. In order to develop an implementation plan for the ART initiative, an international and interdisciplinary workshop is currently planned to take place in Winnipeg, Canada in October 2010

    A total environment of change: exploring social-ecological shifts in subsistence fisheries in Noatak and Selawik, Alaska

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    Thesis (M.S.) University of Alaska Fairbanks, 2012Arctic ecosystems are undergoing rapid changes as a result of global climate change, with significant implications for the livelihoods of arctic peoples. In this thesis, I use ethnographic research methods to detail prominent environmental changes observed and experienced over the past few decades and to document the impact of these changes on subsistence fishing practices in the Inupiaq communities of Noatak and Selawik in northwestern Alaska. Using in-depth key informant interviews, participant observation, and cultural consensus analysis, I explore local knowledge and perceptions of climate change and other pronounced changes facing the communities of Noatak and Selawik. I find consistent agreement about a range of perceived environmental changes affecting subsistence fisheries in this region, including lower river water levels, decreasing abundances of particular fish species, increasingly unpredictable weather conditions, and increasing presence of beaver, which affect local waterways and fisheries. These observations of environmental changes are not perceived as isolated phenomena, but are experienced in the context of accompanying social changes that are continually reshaping rural Alaska communities and subsistence economies. Consequently, in order to properly assess and understand the impacts of climate change on the subsistence practices in arctic communities, we must also consider the total environment of change that is dramatically shaping the relationship between people, communities, and their surrounding environments.U.S. Fish and Wildlife Service, Office of Subsistence Management, Project Number 10-152, Research Work Order number G10AC00473 from the U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, U.S. National Park Service, George Wright Melendenz Climate Change Fellowship, Alaska NSF EPSCoR ProgramIntroduction : arctic climate change and research approach -- Research methods and data analysis -- Noatak and Selawik : patterns of change and continuity -- Observations of climate change and impacts on subsistence fishing -- Climate change in the context of a total environment of change -- Assessing agreement about observations and perceptions of climate change -- Synthesis and future directions -- References -- Appendix

    Emerging Technologies and Approaches for In Situ, Autonomous Observing in the Arctic

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    Understanding and predicting Arctic change and its impacts on global climate requires broad, sustained observations of the atmosphere-ice-ocean system, yet technological and logistical challenges severely restrict the temporal and spatial scope of observing efforts. Satellite remote sensing provides unprecedented, pan-Arctic measurements of the surface, but complementary in situ observations are required to complete the picture. Over the past few decades, a diverse range of autonomous platforms have been developed to make broad, sustained observations of the ice-free ocean, often with near-real-time data delivery. Though these technologies are well suited to the difficult environmental conditions and remote logistics that complicate Arctic observing, they face a suite of additional challenges, such as limited access to satellite services that make geolocation and communication possible. This paper reviews new platform and sensor developments, adaptations of mature technologies, and approaches for their use, placed within the framework of Arctic Ocean observing needs

    Predicting September sea ice: Ensemble skill of the SEARCH Sea Ice Outlook 2008-2013

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    Abstract Since 2008, the Study of Environmental Arctic Change Sea Ice Outlook has solicited predictions of September sea-ice extent from the Arctic research community. Individuals and teams employ a variety of modeling, statistical, and heuristic approaches to make these predictions. Viewed as monthly ensembles each with one or two dozen individual predictions, they display a bimodal pattern of success. In years when observed ice extent is near its trend, the median predictions tend to be accurate. In years when the observed extent is anomalous, the median and most individual predictions are less accurate. Statistical analysis suggests that year-to-year variability, rather than methods, dominate the variation in ensemble prediction success. Furthermore, ensemble predictions do not improve as the season evolves. We consider the role of initial ice, atmosphere and ocean conditions, and summer storms and weather in contributing to the challenge of sea-ice prediction. Key Points Analysis of Sea Ice Outlook contributions 2008-2013 shows bimodal success Years when observations depart from trend are hard to predict despite preconditioning Yearly conditions dominate variations in ensemble prediction success

    Factors Driving Mercury Variability in the Arctic Atmosphere and Ocean over the Past 30 Years

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    [1] Long-term observations at Arctic sites (Alert and Zeppelin) show large interannual variability (IAV) in atmospheric mercury (Hg), implying a strong sensitivity of Hg to environmental factors and potentially to climate change. We use the GEOS-Chem global biogeochemical Hg model to interpret these observations and identify the principal drivers of spring and summer IAV in the Arctic atmosphere and surface ocean from 1979–2008. The model has moderate skill in simulating the observed atmospheric IAV at the two sites (r ~ 0.4) and successfully reproduces a long-term shift at Alert in the timing of the spring minimum from May to April (r = 0.7). Principal component analysis indicates that much of the IAV in the model can be explained by a single climate mode with high temperatures, low sea ice fraction, low cloudiness, and shallow boundary layer. This mode drives decreased bromine-driven deposition in spring and increased ocean evasion in summer. In the Arctic surface ocean, we find that the IAV for modeled total Hg is dominated by the meltwater flux of Hg previously deposited to sea ice, which is largest in years with high solar radiation (clear skies) and cold spring air temperature. Climate change in the Arctic is projected to result in increased cloudiness and strong warming in spring, which may thus lead to decreased Hg inputs to the Arctic Ocean. The effect of climate change on Hg discharges from Arctic rivers remains a major source of uncertainty.Earth and Planetary SciencesEngineering and Applied Science

    Governing Maritime Transportation in the Arctic

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    Historic observations and projected models show a trend of declining sea-ice in the Arctic as a result of global climate change. Sea-ice is the largest obstacle to Arctic maritime transportation, and given these predictions, reductions of sea-ice extent in the Arctic Ocean will create new opportunities for the global transportation industry by opening up navigable passages. For this industry, the Arctic represents efficiencies via time and fuel saving routes and greater connectivity between major international ports. This paper synthesizes international, regional, and national scale governance regimes that collectively manage jurisdictional, infrastructural, and environmental issues of maritime transportation activities in the Arctic. The primary regimes in the Arctic are the United Nations Convention on the Law of the Sea (UNCLOS), the International Maritime Organization (IMO), the Arctic Council, national regimes, and the private transportation sector. Drawing on contemporary understandings of governance, these governance regimes are evaluated based on seven principles of global environmental governance. Existing governance institutions successfully contribute to overall governance in the region, yet there are still gaps that impair Arctic governance from functioning as a cohesive form of global environmental governance. Of the various governance regimes proposed by Arctic scholars to manage the changing region, I argue for an expansion of the Arctic Council that would facilitate a networked governance regime in the Arctic. A networked regime – a combination of multilevel, niche, and hybrid governance – recognizes the successful attributes of existing regimes and strives to connect them all in a network of governance to collectively and comprehensively manage the natural resources of a region. Growing maritime transportation activities in the Arctic will face opportunities and threats associated with the environmental, political, and socioeconomic conditions unique to the region. A networked governance regime in the Arctic would effectively manage the maritime transportation industry to mitigate and minimize environmental harms while achieving the greatest resource benefits for society

    A full year of aerosol size distribution data from the central Arctic under an extreme positive Arctic Oscillation : insights from the Multidisciplinarydrifting Observatory for the Study of Arctic Climate (MOSAiC) expedition

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    The Arctic environment is rapidly changing due to accelerated warming in the region. The warming trend is driving a decline in sea ice extent, which thereby enhances feedback loops in the surface energy budget in the Arctic. Arctic aerosols play an important role in the radiative balance and hence the climate response in the region, yet direct observations of aerosols over the Arctic Ocean are limited. In this study, we investigate the annual cycle in the aerosol particle number size distribution (PNSD), particle number concentration (PNC), and black carbon (BC) mass concentration in the central Arctic during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. This is the first continuous, year-long data set of aerosol PNSD ever collected over the sea ice in the central Arctic Ocean. We use a k-means cluster analysis, FLEXPART simulations, and inverse modeling to evaluate seasonal patterns and the influence of different source regions on the Arctic aerosol population. Furthermore, we compare the aerosol observations to land-based sites across the Arctic, using both long-term measurements and observations during the year of the MOSAiC expedition (2019-2020), to investigate interannual variability and to give context to the aerosol characteristics from within the central Arctic. Our analysis identifies that, overall, the central Arctic exhibits typical seasonal patterns of aerosols, including anthropogenic influence from Arctic haze in winter and secondary aerosol processes in summer. The seasonal pattern corresponds to the global radiation, surface air temperature, and timing of sea ice melting/freezing, which drive changes in transport patterns and secondary aerosol processes. In winter, the Norilsk region in Russia/Siberia was the dominant source of Arctic haze signals in the PNSD and BC observations, which contributed to higher accumulation-mode PNC and BC mass concentrations in the central Arctic than at land-based observatories. We also show that the wintertime Arctic Oscillation (AO) phenomenon, which was reported to achieve a record-breaking positive phase during January-March 2020, explains the unusual timing and magnitude of Arctic haze across the Arctic region compared to longer-term observations. In summer, the aerosol PNCs of the nucleation and Aitken modes are enhanced; however, concentrations were notably lower in the central Arctic over the ice pack than at land-based sites further south. The analysis presented herein provides a current snapshot of Arctic aerosol processes in an environment that is characterized by rapid changes, which will be crucial for improving climate model predictions, understanding linkages between different environmental processes, and investigating the impacts of climate change in future Arctic aerosol studies.Peer reviewe

    Spatial variability of aircraft-measured surface energy fluxes in permafrost landscapes

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    Arctic ecosystems are undergoing a very rapid change due to global warming and their response to climate change has important implications for the global energy budget. Therefore, it is crucial to understand how energy fluxes in the Arctic will respond to any changes in climate related parameters. However, attribution of these responses is challenging because measured fluxes are the sum of multiple processes that respond differently to environmental factors. Here, we present the potential of environmental response functions for quantitatively linking energy flux observations over high latitude permafrost wetlands to environmental drivers in the flux footprints. We used the research aircraft POLAR 5 equipped with a turbulence probe and fast temperature and humidity sensors to measure turbulent energy fluxes along flight tracks across the Alaskan North Slope with the aim to extrapolate the airborne eddy covariance flux measurements from their specific footprint to the entire North Slope. After thorough data pre-processing, wavelet transforms are used to improve spatial discretization of flux observations in order to relate them to biophysically relevant surface properties in the flux footprint. Boosted regression trees are then employed to extract and quantify the functional relationships between the energy fluxes and environmental drivers. Finally, the resulting environmental response functions are used to extrapolate the sensible heat and water vapor exchange over spatio-temporally explicit grids of the Alaskan North Slope. Additionally, simulations from the Weather Research and Forecasting (WRF) model were used to explore the dynamics of the atmospheric boundary layer and to examine results of our extrapolation

    One Health

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    As a result of the close relationships between Arctic residents and the environment, climate change has a disproportionate impact on Arctic communities. Despite the need for One Health responses to climate change, environmental monitoring is difficult to conduct in Arctic regions. The Local Environmental Observer (LEO) Network is a global social media network that recruits citizen scientists to collect environmental observations on social media. We examined the processes of the LEO Network, numbers of members and observations, and three case studies that depict One Health action enabled by the system. From February 2012 to July 2017, the LEO Network gained 1870 members in 35 countries. In this time period, 670 environmental observations were posted. Examples that resulted in One Health action include those involving food sources, wild fire smoke, and thawing permafrost. The LEO network is an example of a One Health resource that stimulates action to protect the health of communities around the world.20182018-10-11T00:00:00Z30386813PMC6205347649

    Arctic air pollution: Challenges and opportunities for the next decade

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    The Arctic is a sentinel of global change. This region is influenced by multiple physical and socio-economic drivers and feedbacks, impacting both the natural and human environment. Air pollution is one such driver that impacts Arctic climate change, ecosystems and health but significant uncertainties still surround quantification of these effects. Arctic air pollution includes harmful trace gases (e.g. tropospheric ozone) and particles (e.g. black carbon, sulphate) and toxic substances (e.g. polycyclic aromatic hydrocarbons) that can be transported to the Arctic from emission sources located far outside the region, or emitted within the Arctic from activities including shipping, power production, and other industrial activities. This paper qualitatively summarizes the complex science issues motivating the creation of a new international initiative, PACES (air Pollution in the Arctic: Climate, Environment and Societies). Approaches for coordinated, international and interdisciplinary research on this topic are described with the goal to improve predictive capability via new understanding about sources, processes, feedbacks and impacts of Arctic air pollution. Overarching research actions are outlined, in which we describe our recommendations for 1) the development of trans-disciplinary approaches combining social and economic research with investigation of the chemical and physical aspects of Arctic air pollution; 2) increasing the quality and quantity of observations in the Arctic using long-term monitoring and intensive field studies, both at the surface and throughout the troposphere; and 3) developing improved predictive capability across a range of spatial and temporal scales
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