Sample records for prognostic arctic ice-ocean

  1. Modeling the seasonal variability of a coupled Arctic ice-ocean system (United States)

    Hakkinen, Sirpa; Mellor, George L.


    The seasonal variability of the ice-ocean system in the Arctic Basin and the Norwegian, Greenland, and Barents Seas was modeled using a three-dimensional coupled ice-ocean model developed at Princeton University. The snow-ice model uses a three-level thermodynamic scheme similar to Semtner's (1976), but is extended to include the effect of leads. It is shown that simulations using the climatological monthly forcing fields produce a realistic seasonal variability of the ice cover. The ice thickness had a considerable sensitivity to the choice of the long-wave back radiation scheme, but these effects can be reduced through dynamical factors.

  2. Ice, Ocean and Atmosphere Interactions in the Arctic Marginal Ice Zone (United States)


    release; distribution is unlimited. DRI TECHNICAL PROGRAM: Emerging Dynamics Of The Marginal Ice Zone Ice, Ocean and Atmosphere Interactions in the...Arctic Marginal Ice Zone Year 4 Annual Report Jeremy Wilkinson British Antarctic Survey phone: 44 (0)1223 221489 fax: 44 (0) LONG-TERM GOALS This DRI TECHNICAL PROGRAM (Emerging Dynamics Of The Marginal Ice Zone) brings together a high-level

  3. An Arctic Ice/Ocean Coupled Model with Wave Interactions (United States)


    New Zealand phone: +64 (3) 479-8303 email: Award Number: N00014-131-0279∼vsquire LONG...Symposium on Ice, Singapore, August 2014. Squire, V. A. Perspectives of ocean wave / sea ice connectivity relating to climate change and modelling...contemporary Arctic climate models. OBJECTIVES To make progress with our long-term goals, over the lifetime of the project we will – further our

  4. An Arctic Ice/Ocean Coupled Model with Wave Interactions (United States)


    therefore enhances positive ice- albedo temperature feedback by bringing warmer water in contact with the decaying ice mass. In tandem, aggregated fetch...past a solitary sheet of floating plastic with prescribed physical properties and by an array of floating disks, potentially provide a rich source of...Arctic sea ice has experienced since at least the beginning of the satellite era are believed to be caused by ice- albedo temperature feedback

  5. Evolution of a Western Arctic Ice Ocean Boundary Layer and Mixed Layer Across a Developing Thermodynamically Forced Marginal Ice Zone (United States)


    in the Canada Basin seasonal ice zone. The subsections below outline the new contributions to the field of Arctic ice-ocean science discovered during...doi:10.1002/2013GL058956. Paulson, C.A. and W. S. Pegau, 2001: The summertime thermohaline evolution of an Arctic lead: Heat budget of the surface...Menge, 2010: Influences of the ocean surface mixed layer and thermohaline stratification on Arctic Sea ice in the central Canada Basin. J. Geophys. Res

  6. Sensitivity of the Regional Arctic System Model surface climate to ice-ocean state (United States)

    Roberts, A.; Maslowski, W.; Osinski, R.; Cassano, J. J.; Craig, A.; Duvivier, A.; Fisel, B. J.; Gutowski, W. J.; Higgins, M.; Hughes, M. R.; Lettenmaier, D. P.; Nijssen, B.


    The Regional Arctic System Model (RASM) is a high-resolution Earth System model extending across the Arctic Ocean, its marginal seas, the Arctic drainage basin, and including the Coordinated Regional Downscaling Experiment (CORDEX) Arctic domain. RASM uses the flux coupler (CPL7) within the Community Earth System Model framework to couple regional configurations of the Weather Research and Forecasting model (WRF), Parallel Ocean Program (POP), Los Alamos sea ice model (CICE), and Variable Infiltration Capacity land hydrology model (VIC). Work is also underway to incorporate the Community Ice Sheet Model (CISM) as well as glacier, ice cap and dynamic vegetation models. As part of RASM development, coupled simulations are being prepared for the CORDEX Arctic domain, which is unique among CORDEX regions by being centered over the ocean. Up to this point, there has been uncertainty over how much initial and surface conditions in the ice-ocean boundary layer influence the surface climate of the Arctic in RASM, relative to regional atmospheric model constraints, such as spectral nudging and boundary conditions. We present results that suggest there is a significant dependency on the initial sea ice conditions on decadal timescales within RASM. This has important implications for (i) how results from different regional artic models may be combined and compared in CORDEX and (ii) appropriate methods for ensemble generation in regional polar models. We will also present results illustrating the influence of sub-hourly sea ice deformation on decadal climate in RASM, highlighting an important reason why fully coupled and high-resolution regional models are essential for regional Arctic downscaling.

  7. A distributed atmosphere-sea ice-ocean observatory in the central Arctic Ocean: concept and first results (United States)

    Hoppmann, Mario; Nicolaus, Marcel; Rabe, Benjamin; Wenzhöfer, Frank; Katlein, Christian; Scholz, Daniel; Valcic, Lovro


    To understand the current evolution of the Arctic Ocean towards a less extensive, thinner and younger sea ice cover is one of the biggest challenges in climate research. Especially the lack of simultaneous in-situ observations of sea ice, ocean and atmospheric properties leads to significant knowledge gaps in their complex interactions, and how the associated processes impact the polar marine ecosystem. Here we present a concept for the implementation of a long-term strategy to monitor the most essential climate- and ecosystem parameters in the central Arctic Ocean, year round and synchronously. The basis of this strategy is the development and enhancement of a number of innovative autonomous observational platforms, such as rugged weather stations, ice mass balance buoys, ice-tethered bio-optical buoys and upper ocean profilers. The deployment of those complementing platforms in a distributed network enables the simultaneous collection of physical and biogeochemical in-situ data on basin scales and year round, including the largely undersampled winter periods. A key advantage over other observatory systems is that the data is sent via satellite in near-real time, contributing to numerical weather predictions through the Global Telecommunication System (GTS) and to the International Arctic Buoy Programme (IABP). The first instruments were installed on ice floes in the Eurasian Basin in spring 2015 and 2016, yielding exceptional records of essential climate- and ecosystem-relevant parameters in one of the most inaccessible regions of this planet. Over the next 4 years, and including the observational periods of the Year of Polar Prediction (YOPP, 2017-2019) and the Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC, 2020), the distributed observatory will be maintained by deployment of additional instruments in the central Arctic each year, benefitting from international logistical efforts.

  8. Evidence for ice-ocean albedo feedback in the Arctic Ocean shifting to a seasonal ice zone. (United States)

    Kashiwase, Haruhiko; Ohshima, Kay I; Nihashi, Sohey; Eicken, Hajo


    Ice-albedo feedback due to the albedo contrast between water and ice is a major factor in seasonal sea ice retreat, and has received increasing attention with the Arctic Ocean shifting to a seasonal ice cover. However, quantitative evaluation of such feedbacks is still insufficient. Here we provide quantitative evidence that heat input through the open water fraction is the primary driver of seasonal and interannual variations in Arctic sea ice retreat. Analyses of satellite data (1979-2014) and a simplified ice-upper ocean coupled model reveal that divergent ice motion in the early melt season triggers large-scale feedback which subsequently amplifies summer sea ice anomalies. The magnitude of divergence controlling the feedback has doubled since 2000 due to a more mobile ice cover, which can partly explain the recent drastic ice reduction in the Arctic Ocean.

  9. Toward Quantifying the Impact of Atmospheric Forcing on Arctic Sea Ice Variability Using the NPS 1/12 Degree Pan-Arctic Coupled Ice-Ocean Model (United States)


    higher than average with 2008 following close behind at 4°C above average (Richter-Menge et al. 2008). Global climate models predict a continual Arctic...animal ecosystems, and increases the likelihood of weather and precipitation extremes. The Northern Hemisphere treeline is projected to progress...communities, including naval military bases such as Diego Garcia, which sits just four meters above sea level (Military Sealift Command n.d.). Furthermore

  10. Towards Prediction of Environmental Arctic Change

    National Research Council Canada - National Science Library

    Maslowski, Wieslaw


    Our main objective is to use models of the coupled ice-ocean Arctic environment to understand the past and present sea ice and ocean states and to predict future scenarios of environmental change in the Arctic Ocean...

  11. Submesoscale Sea Ice-Ocean Interactions in Marginal Ice Zones (United States)

    Manucharyan, Georgy E.; Thompson, Andrew F.


    Signatures of ocean eddies, fronts, and filaments are commonly observed within marginal ice zones (MIZs) from satellite images of sea ice concentration, and in situ observations via ice-tethered profilers or underice gliders. However, localized and intermittent sea ice heating and advection by ocean eddies are currently not accounted for in climate models and may contribute to their biases and errors in sea ice forecasts. Here, we explore mechanical sea ice interactions with underlying submesoscale ocean turbulence. We demonstrate that the release of potential energy stored in meltwater fronts can lead to energetic submesoscale motions along MIZs with spatial scales O(10 km) and Rossby numbers O(1). In low-wind conditions, cyclonic eddies and filaments efficiently trap the sea ice and advect it over warmer surface ocean waters where it can effectively melt. The horizontal eddy diffusivity of sea ice mass and heat across the MIZ can reach O(200 m2 s-1). Submesoscale ocean variability also induces large vertical velocities (order 10 m d-1) that can bring relatively warm subsurface waters into the mixed layer. The ocean-sea ice heat fluxes are localized over cyclonic eddies and filaments reaching about 100 W m-2. We speculate that these submesoscale-driven intermittent fluxes of heat and sea ice can contribute to the seasonal evolution of MIZs. With the continuing global warming and sea ice thickness reduction in the Arctic Ocean, submesoscale sea ice-ocean processes are expected to become increasingly prominent.

  12. The role of subpolar atmosphere-ice-ocean interactions in D-O cycles (United States)

    Li, Camille; Born, Andreas


    Sea ice has long been thought to play an important role in D-O cycles because of its strong influence on regional temperature and its ability to grow and melt rapidly in response to relatively weak forcings. One recent idea based on modelling experiments is that D-O-related sea ice displacements are part of an unforced, coupled oscillation of the North Atlantic atmosphere-ice-ocean system. Here, we present an overview of key components of this system, as well as observational and modelling results addressing how they function in today's climate, and how glacial climate conditions might alter their functioning to allow D-O cycles to occur. Of specific interest are the necessary changes in the subpolar gyre, the thermohaline structure and stratification of the Nordic Seas, the existence of an Arctic-like cold halocline at subpolar latitudes, and the accessibility of the subsurface ocean heat reservoir to the atmosphere. Broader consequences for the Atlantic thermohaline circulation and Southern Hemisphere climate signals will be discussed.

  13. Centennial-scale climate change from decadally-paced explosive volcanism: a coupled sea ice-ocean mechanism (United States)

    Zhong, Y.; Miller, G. H.; Otto-Bliesner, B. L.; Holland, M. M.; Bailey, D. A.; Schneider, D. P.; Geirsdottir, A.


    Northern Hemisphere summer cooling through the Holocene is largely driven by the steady decrease in summer insolation tied to the precession of the equinoxes. However, centennial-scale climate departures, such as the Little Ice Age, must be caused by other forcings, most likely explosive volcanism and changes in solar irradiance. Stratospheric volcanic aerosols have the stronger forcing, but their short residence time likely precludes a lasting climate impact from a single eruption. Decadally paced explosive volcanism may produce a greater climate impact because the long response time of ocean surface waters allows for a cumulative decrease in sea-surface temperatures that exceeds that of any single eruption. Here we use a global climate model to evaluate the potential long-term climate impacts from four decadally paced large tropical eruptions. Direct forcing results in a rapid expansion of Arctic Ocean sea ice that persists throughout the eruption period. The expanded sea ice increases the flux of sea ice exported to the northern North Atlantic long enough that it reduces the convective warming of surface waters in the subpolar North Atlantic. In two of our four simulations the cooler surface waters being advected into the Arctic Ocean reduced the rate of basal sea-ice melt in the Atlantic sector of the Arctic Ocean, allowing sea ice to remain in an expanded state for > 100 model years after volcanic aerosols were removed from the stratosphere. In these simulations the coupled sea ice-ocean mechanism maintains the strong positive feedbacks of an expanded Arctic Ocean sea ice cover, allowing the initial cooling related to the direct effect of volcanic aerosols to be perpetuated, potentially resulting in a centennial-scale or longer change of state in Arctic climate. The fact that the sea ice-ocean mechanism was not established in two of our four simulations suggests that a long-term sea ice response to volcanic forcing is sensitive to the stability of the seawater

  14. Centennial-scale climate change from decadally-paced explosive volcanism: a coupled sea ice-ocean mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Y. [University of Colorado, INSTAAR, Boulder, CO (United States); Miller, G.H. [University of Colorado, INSTAAR, Boulder, CO (United States); University of Colorado, Department of Geological Sciences, Boulder, CO (United States); Otto-Bliesner, B.L.; Holland, M.M.; Bailey, D.A. [NCAR, Boulder, CO (United States); Schneider, D.P. [NCAR, Boulder, CO (United States); University of Colorado, CIRES, Boulder, CO (United States); Geirsdottir, A. [University of Iceland, Department of Earth Sciences and Institute of Earth Sciences, Reykjavik (Iceland)


    Northern Hemisphere summer cooling through the Holocene is largely driven by the steady decrease in summer insolation tied to the precession of the equinoxes. However, centennial-scale climate departures, such as the Little Ice Age, must be caused by other forcings, most likely explosive volcanism and changes in solar irradiance. Stratospheric volcanic aerosols have the stronger forcing, but their short residence time likely precludes a lasting climate impact from a single eruption. Decadally paced explosive volcanism may produce a greater climate impact because the long response time of ocean surface waters allows for a cumulative decrease in sea-surface temperatures that exceeds that of any single eruption. Here we use a global climate model to evaluate the potential long-term climate impacts from four decadally paced large tropical eruptions. Direct forcing results in a rapid expansion of Arctic Ocean sea ice that persists throughout the eruption period. The expanded sea ice increases the flux of sea ice exported to the northern North Atlantic long enough that it reduces the convective warming of surface waters in the subpolar North Atlantic. In two of our four simulations the cooler surface waters being advected into the Arctic Ocean reduced the rate of basal sea-ice melt in the Atlantic sector of the Arctic Ocean, allowing sea ice to remain in an expanded state for > 100 model years after volcanic aerosols were removed from the stratosphere. In these simulations the coupled sea ice-ocean mechanism maintains the strong positive feedbacks of an expanded Arctic Ocean sea ice cover, allowing the initial cooling related to the direct effect of volcanic aerosols to be perpetuated, potentially resulting in a centennial-scale or longer change of state in Arctic climate. The fact that the sea ice-ocean mechanism was not established in two of our four simulations suggests that a long-term sea ice response to volcanic forcing is sensitive to the stability of the seawater

  15. Evaluating Physical Processes during the Freeze-Up Season using a Coupled Sea Ice-Ocean-Atmosphere Forecast Model (United States)

    Solomon, Amy; Intrieri, Janet; Persson, Ola; Cox, Christopher; Hughes, Mimi; Grachev, Andrey; Capotondi, Antonietta; de Boer, Gijs


    Improved sea ice forecasting must be based on improved model representation of coupled system processes that impact the sea ice thermodynamic and dynamic state. Pertinent coupled system processes remain uncertain and include surface energy fluxes, clouds, precipitation, boundary layer structure, momentum transfer and sea-ice dynamics, interactions between large-scale circulation and local processes, and others. In this presentation, we use a fully-coupled ocean-sea ice-atmosphere forecast system as a testbed for investigating biases in 0-10 day forecasts, with a focus on processes that determine fluxes at the ocean-ice-air interface. Model results and validation examples from an experimental, weather-scale, coupled ice-ocean-atmosphere model for 2015 and 2016 fall, sea ice freeze-up season will be presented. The model, a limited-area, fully-coupled atmosphere-ice-ocean model (named, RASM-ESRL), was developed from the larger-scale Regional Arctic System Model (RASM) architecture. RASM-ESRL includes the Weather Research and Forecasting (WRF) atmospheric model, Parallel Ocean Program (POP2) model, Community Ice Model (CICE5) and the NCAR Community Land Model. The domain is limited to the Arctic and all components are run with 10 km horizontal resolution. Components are coupled using a regionalized version of the CESM flux coupler (CPL7), which includes modifications important for resolving the sea ice pack's inertial response to transient (i.e. weather) events. The model is initialized with a GFS atmosphere, satellite-derived sea ice analyses using AMSR-2, and forced by 3-hourly GFS forecasts at the lateral boundaries. Experimental forecasts were run daily from late-July through mid-November in 2015 and 2016. These daily forecasts have been compared with observations of surface fluxes and vertical atmospheric profiles at the International Arctic Systems for Observing the Atmosphere (IASOA) stations, and with atmospheric and oceanic observations obtained within the sea

  16. Prognostics (United States)

    National Aeronautics and Space Administration — Prognostics has received considerable attention recently as an emerging sub-discipline within SHM. Prognosis is here strictly defined as “predicting the time at...

  17. Radiative transfer in atmosphere-sea ice-ocean system

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Z.; Stamnes, K.; Weeks, W.F. [Univ. of Alaska, Fairbanks, AK (United States); Tsay, S.C. [NASA Goddard Space Flight Center, Greenbelt, MD (United States)


    Radiative energy is critical in controlling the heat and mass balance of sea ice, which significantly affects the polar climate. In the polar oceans, light transmission through the atmosphere and sea ice is essential to the growth of plankton and algae and, consequently, to the microbial community both in the ice and in the ocean. Therefore, the study of radiative transfer in the polar atmosphere, sea ice, and ocean system is of particular importance. Lacking a properly coupled radiative transfer model for the atmosphere-sea ice-ocean system, a consistent study of the radiative transfer in the polar atmosphere, snow, sea ice, and ocean system has not been undertaken before. The radiative transfer processes in the atmosphere and in the ice and ocean have been treated separately. Because the radiation processes in the atmosphere, sea ice, and ocean depend on each other, this separate treatment is inconsistent. To study the radiative interaction between the atmosphere, clouds, snow, sea ice, and ocean, a radiative transfer model with consistent treatment of radiation in the coupled system is needed and is under development.

  18. An Integrated Investigation of the Sea Ice-Ocean Energy Balance using Satellite Remote Sensing, Autonomous In-Situ Observations, and Three-Dimensional Sea Ice Modelling. (United States)

    Wright, N.; Polashenski, C. M.; Skyllingstad, E. D.; Perovich, D. K.


    A key process that exerts control over sea ice mass balance in the Arctic Ocean is the partitioning of incident solar radiation between reflection back to the atmosphere and absorption into the ice and upper ocean. The amount and distribution of solar energy absorbed is highly dependent on the fractional coverage of sea ice surface types. We use a newly developed satellite image processing technique to classify the sea ice surface type into four categories: thick or snow covered ice, thin ice, ponds, and open water. The high resolution optical satellite imagery allows us to quantify the evolution of surrounding ice conditions, including melt pond coverage and floe size distribution, at a sub-meter scale over scenes of approximately 700km2. We integrate these results with in-situ measurements collected by Arctic Observing Network (AON) sites and reanalysis products from the National Centers for Environmental Prediction and European Centre for Medium-Range Weather Forecasts. AON assets, including ice mass balance buoys and ice tethered profilers, monitor the storage and fluxes of heat in the ice-ocean system, while the reanalysis products inform the long and shortwave radiation fluxes through cloud fraction and cloud temperature. These datasets provide a series of snapshots of the surface types, snow and ice characteristics, and radiative fluxes. We use a resolved sea ice model (RSIM) to integrate these snapshots, filling in the temporal gaps to develop a physically-based description of the ice-ocean system at the AON sites over time. The combined representation of the ice-ocean system is used to evaluate the absorption, storage, and release of solar shortwave energy and its effect on the sea ice mass balance.

  19. Energizing the Discussion of Ice-Ocean World Habitability (United States)

    Schmidt, B.


    The outer solar system boasts a wide range of worlds with oceans - moons orbiting the gas giants as well as putative ocean worlds in the Kuiper Belt. These objects span sizes from a few hundred kilometers to larger than Mercury. How do we understand these bodies as a class as well as evaluate the habitability of individual environments? Recognizing that there is more to habitability than a set of ingredients, "Follow the Energy' has become an important mantra. Earth's biosphere is strongly coupled to its geologic activity that maintains a sort of stable chemical disequilibria that is employed by life. From this perspective, we can think of geologic activity as a planetary proxy for energy, setting up redox environments of which life can take advantage. With this as a backdrop, we will explore two of the most intriguing bodies: Europa and Enceladus. With an icy outer shell hiding a global ocean, Europa (r=1565 km) exists in a dynamic environment, where immense tides from Jupiter potentially power an active deeper interior. Intense irradiation and impacts bathe the top of the ice shell. These processes are sources of energy that could sustain a biosphere. In the past few decades the debate about habitability of Europa has been focused strongly on the thickness of its ice shell. However an arguably more critical question is: how does the ice shell really work? Galileo data indicated that Europa has undergone recent resurfacing, and implied that near-surface water was likely involved. Now the detection of potential water ice plumes, subduction-like behavior as well as shallow subsurface "lakes" within the past few years implies that rapid ice shell recycling could create a conveyor belt between the ice and ocean. Mediated by processes at the ice-ocean interface, exchange between Europa's surface and subsurface could allow ocean material to one day be detected or sampled by spacecraft. At least at this level, Europa passes the energy test. But the question remains: is

  20. Insights Into Ice-Ocean Interactions on Earth and Europa (United States)

    Lawrence, J.; Schmidt, B. E.; Winslow, L.; Doran, P. T.; Kim, S.; Walker, C. C.; Buffo, J.; Skidmore, M. L.; Soderlund, K. M.; Blankenship, D. D.; Bramall, N. E.; Johnson, A.; Rack, F. R.; Stone, W.; Kimball, P.; Clark, E.


    Europa and Earth appear to be drastically different worlds, yet below their icy crusts the two likely share similar oceanic conditions including temperatures, pressures (relatively), and salinity. Earth's ice shelves provide an important analog for the physiochemical, and potentially microbial, characteristics of icy worlds. NASA's ASTEP program funded Sub-Ice Marine and PLanetary-analog Ecosystems (SIMPLE) to help address the fundamental processes occurring at ice ocean interfaces, the extent and limitations of life in sub-ice environments, and how environmental properties and biological communities interact. The relationships between currents, temperature, and salinity with physical processes such as melt, freeze, and marine ice accretion at the basal surfaces of ice shelves influence habitability yet are poorly understood even on Earth. Resultant processes such as the inclusion of ocean-derived material in ice shelves and the transport of biotics from the interface towards the surface via ablation, convection, and diapirism also have important astrobiological implications for Europa.Here, we present results from CTD and imaging data gathered at multiple locations beneath the McMurdo Ice Shelf (MIS) to highlight how the ice and ocean interact in a Europan analog environment. Over the course of three years, the SIMPLE team observed heterogeneity in the water column and basal ice beneath the MIS. During the recent 2015 field season we deployed ARTEMIS, an AUV capable of characterizing the interface over multiple kilometer missions, and conducted daily CTD casts to 480 m (bottom depth 529 m) in November adjacent to the terminus of the MIS to capture temporal variation in the water column. These casts show the presence of transient water masses related to the tidal period, each containing a single or double temperature minimum (down to -1.97 °C from -1.93 °C) between 60 to 150 m depth. Further comparisons between years and sampling locations demonstrate the

  1. The Ice Ocean Sentinel System (IOSS): Working towards Ice and Ocean Observation Technologies for Remote and Harsh Environments (United States)

    Bachmayer, R.; DeYoung, B.


    The need for a significant increase in observational capabilities of the underwater environment in harsh ice-covered environments is to a significant amount driven by expanding developments in the offshore regions of the Northwest Atlantic from Newfoundland to Western Greenland and the opening up of the sub-Arctic and Arctic regions. These regions are characterized by their remoteness, seasonally varying ice-cover and a susceptibility to extreme weather events. Existing oceanographic information about these regions is sparse and in the case of ice-covered regions often non-existent. Nonetheless crucial decisions for design and operations in these regions have to be based on realistic assumptions.As part of the Ice Ocean Sentinel System (IOSS) we are currently developping a new observation system along with approaches for the provision of atmospheric and ocean data and information products for these regions. We approach this objective by combining existing and field-proven technologies, such as underwater glider type Autonomous Underwater Vehicles (AUVs), acoustic imaging systems and COTS ocean water property sensors in new ways, and adding communication and navigation pathways to interconnect these elements.This project work involves several stages, from development, through testing to operational deployments. The objective is to create an integrated system comprising four technologies, underwater gliders, unmanned surface craft, shore-side data collection and automated processing and visualization capabilities. Those elements, used together or in various combinations, will provide decision making information for maritime and offshore energy operations as well as data for improved ice, iceberg and ocean modelling and prediction capabilites.We will provide an overview of the 2014/2015 field trials around Newfoundland, testing glider and USV based iceberg mapping and tracking capabilities. Furthermore, we will report on the progress of the development of a novel semi

  2. Wave-Ice and Air-Ice-Ocean Interaction During the Chukchi Sea Ice Edge Advance (United States)


    ice . The ROV and all sensors were tested extensively at WHOI. This platform will complement the AUV by performing rapid, short under ice ...Bruncin, 3) two WHOI-built IMBs also equipped with acoustic snow depth sensors and CTDs, and 4) one CRREL Seasonal Sea Ice Zone IMB. In addition, an...1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Wave- Ice and Air- Ice -Ocean Interaction During the

  3. Reconciling heat-flux and salt-flux estimates at a melting ice-ocean interface

    CERN Document Server

    Keitzl, Thomas; Notz, Dirk


    The ratio of heat and salt flux is employed in ice-ocean models to represent ice-ocean interactions. In this study, this flux ratio is determined from direct numerical simulations of free convection beneath a melting, horizontal, smooth ice-ocean interface. We find that the flux ratio at the interface is three times as large as previously assessed based on turbulent-flux measurements in the field. As a consequence, interface salinities and melt rates are overestimated by up to 40\\% if they are based on the three-equation formulation. We also find that the interface flux ratio depends only very weakly on the far-field conditions of the flow. Lastly, our simulations indicate that estimates of the interface flux ratio based on direct measurements of the turbulent fluxes will be difficult because at the interface the diffusivities alone determine the mixing and the flux ratio varies with depth. As an alternative, we present a consistent evaluation of the flux ratio based on the total heat and salt fluxes across t...

  4. Simulating the evolution of Thwaites Glacier with a coupled ice-ocean model (United States)

    Seroussi, Helene; Nakayama, Yoshihiro; Menemenlis, Dimitris; Larour, Eric; Morlighem, Mathieu; Rignot, Eric; Khazendar, Ala


    Ice shelves and floating glacier termini play an important role in the stability of ice sheets and interact strongly with the ocean. They account for much of the buttressing against the flow of inland glaciers that drain the Antarctic ice sheet. Changes in their geometry due to ice-front retreat, thinning or even collapse profoundly affect the flow of their tributary glaciers, which in turn affects the volume of grounded ice carried by these tributary glaciers into the ocean, and the extent of resulting sea level rise. Recent simulations of glaciers in Antarctica show that the largest climatic impact on ice dynamics is the rate of ice shelf melting, which rapidly affects glaciers' speed over several hundreds of kilometers upstream of the grounding line. However, accurate knowledge of these melting rates, as well as their spatial and temporal evolution remain largely unknown. Coupled ice-ocean models are the best available approach to address this question. In this study, we focus on Thwaites glacier in the Amundsen Sea sector, a glacier that has been accelerating, widening and experiencing a complex grounding line retreat pattern over the past three decades. We simulate the coupled ice-ocean system using a new two-way coupled system between the Massachusetts Institute of Technology general circulation model (MITgcm) and the Ice Sheet System Model (ISSM). We investigate the feedbacks between changes in the ice and ocean, and the dynamic response of the glacier to changes in the ocean circulation. Our results reproduce the grounding line retreat and ice flow acceleration observed over the last couple decades, and show the rapid adjustment of ocean-induced melting rates to the evolution of the sub-ice shelf cavity, demonstrating the importance of simulating the coupled ice-ocean system to produce accurate melting rates under the ice shelf and at the grounding line. The simulations suggest that Thwaites Glacier is likely to undergo substantial changes in the coming

  5. Exploration of the Climate Change Frontier in Polar Regions at the Land Ice-Ocean Boundary. (United States)

    Rignot, E. J.


    Ice sheets are the largest contributors to sea level rise at present, and responsible for the largest uncertainty in sea level projections. Ice sheets raised sea level 5 m per century 13.5 kyr ago during one period of rapid change. Leading regions for future rapid changes include the marine-based, retrograde bed parts of Greenland (north center and east), West Antarctica (Amundsen Sea), and East Antarctica (Filchner basin and Wilkes Land). Fast changes require an increase in ice melt from a warmer ocean and an increase in iceberg calving. Our understanding of both processes remains limited due to a lack of basic observations. Understanding ocean forcing requires observations on the continental shelf, along bays and glacial fjords and at ice-ocean boundaries, beneath kilometers of ice (Antarctica) or at near-vertical calving cliffs (Greenland), of ocean temperature and sea floor bathymetry. Where such observations exist, the sea floor is much deeper than anticipated because of the carving of deep channels by multiple glacier advances. Warm subsurface waters penetrate throughout the Amundsen Sea Embayment of West Antarctica, the southeast and probably the entire west coasts of Greenland. In Greenland, discharge of subglacial water from surface runoff at the glacier grounding line increases ice melting by the ocean even if the ocean temperature remains the same. Near ice-ocean boundaries, satellite observations are challenged, airborne observations and field surveys are limited, so advanced robotic techniques for cold, deep, remote environments are ultimately required in combination with advanced numerical modeling techniques. Until such technological advances take place and advanced networks are put in place, it is critical to conduct boat surveys, install moorings, and conduct extensive airborne campaigns (for instance, gravity-derived bathymetry and air-dropped CTDs), some of which is already taking place. In the meantime, projections of ice sheet evolution in a

  6. A coupled dynamic-thermodynamic model of an ice-ocean system in the marginal ice zone (United States)

    Hakkinen, Sirpa


    Thermodynamics are incorporated into a coupled ice-ocean model in order to investigate wind-driven ice-ocean processes in the marginal zone. Upswelling at the ice edge which is generated by the difference in the ice-air and air-water surface stresses is found to give rise to a strong entrainment by drawing the pycnocline closer to the surface. Entrainment is shown to be negligible outside the areas affected by the ice edge upswelling. If cooling at the top is included in the model, the heat and salt exchanges are further enhanced in the upswelling areas. It is noted that new ice formation occurs in the region not affected by ice edge upswelling, and it is suggested that the high-salinity mixed layer regions (with a scale of a few Rossby radii of deformation) will overturn due to cooling, possibly contributing to the formation of deep water.

  7. Sensitivity of a global ice-ocean model to the Bering Strait throughflow

    Energy Technology Data Exchange (ETDEWEB)

    Goosse, H. [Universite Catholique de Louvain (UCL), Louvain-la-Neuve (Belgium). Inst. d`Astronomie et de Geophysique G. Lemaitre; Campin, J.M. [Universite Catholique de Louvain (UCL), Louvain-la-Neuve (Belgium). Inst. d`Astronomie et de Geophysique G. Lemaitre; Fichefet, T. [Universite Catholique de Louvain (UCL), Louvain-la-Neuve (Belgium). Inst. d`Astronomie et de Geophysique G. Lemaitre; Deleersnijder, E. [Universite Catholique de Louvain (UCL), Louvain-la-Neuve (Belgium). Inst. d`Astronomie et de Geophysique G. Lemaitre


    To understand the influence of the Bering Strait on the World Ocean`s circulation, a model sensitivity analysis is conducted. The numerical experiments are carried out with a global, coupled ice-ocean model. The water transport through the Bering Strait is parametrized according to the geostrophic control theory. The model is driven by surface fluxes derived from bulk formulae assuming a prescribed atmospheric seasonal cycle. In addition, a weak restoring to observed surface salinities is applied to compensate for the global imbalance of the imposed surface freshwater fluxes. The freshwater flux from the North Pacific to the North Atlantic associated with the Bering Strait throughflow seems to be an important element in the freshwater budget of the Greenland and Norwegian seas and of the Atlantic. This flux induces a freshening of the North Atlantic surface waters, which reduces the convective activity and leads to a noticeable (6%) weakening of the thermohaline conveyor belt. It is argued that the contrasting results obtained by Reason and Power are due to the type of surface boundary conditions they used. (orig.). With 8 figs.


    Directory of Open Access Journals (Sweden)

    Yelena Polyakova


    Full Text Available The overview of the 20-years joint Russian-German multidisciplinary researches in the Arctic are represented in this article. Data were obtained during numerous marine and terrestrial expeditions, all-year-round measurements and observations. On the basis of modern research methods including satellite observation, radiocarbon (AMS 14C dating of the Arctic sea sediments, isotope, biochemical and other methods, the new unique records were obtained. Special emphasis devoted to the latest data concerning modern sea-ice, ocean and sedimentation processes, evolution of the permafrost and paleoenvironments in the Laptev Sea System.

  9. Modelling subglacial drainage and its role in ice-ocean interaction (United States)

    Hewitt, Ian; Dallaston, Michael; Wells, Andrew


    Melting at the ice-ocean interface, both beneath ice shelves and at near-vertical tidewater margins, is strongly influenced by discharge of meltwater from beneath the grounded ice. The fresh water source can help to initiate a buoyant plume that rises up the ice face, entraining heat from the ocean to melt the ice. When the subglacial discharge is spatially and temporally variable, it can cause spatial and temporal variations in the melting rate, which in turn may influence ocean circulation in the cavity and ice flow within the shelf. Recent observations of channelized ice shelf bases may have their origin in variable subglacial discharge from beneath the grounded ice. In this work, we use physically-based models of the subglacial drainage system to examine the likely mode of melt water delivery across the grounding line. We find that if subglacial channels (Rothlisberger channels) exist they can be expected to `trumpet' out as the ocean is approached, due to a lack of confining stress to counteract wall melting. This causes a reduction in horizontal momentum in the water and can lead to pronounced localized melting around channel termini. This may lead to increased propensity for calving at such locations. We also examine the effect of subglacial discharge variations on the evolution of a downstream floating ice shelf. We find that lateral variations in the flow across the grounding line can result in variations in plume-driven melting which evolve to create basal channels in the shelf aligned with the flow. The preferred spacing of the channels is controlled by a balance between buoyancy-driven acceleration and turbulent mixing in the ocean layer.

  10. Ice-ocean interaction and calving front morphology at two west Greenland tidewater outlet glaciers (United States)

    Chauché, N.; Hubbard, A.; Gascard, J.-C.; Box, J. E.; Bates, R.; Koppes, M.; Sole, A.; Christoffersen, P.; Patton, H.


    Warm, subtropical-originating Atlantic water (AW) has been identified as a primary driver of mass loss across the marine sectors of the Greenland Ice Sheet (GrIS), yet the specific processes by which this water mass interacts with and erodes the calving front of tidewater glaciers is frequently modelled and much speculated upon but remains largely unobserved. We present a suite of fjord salinity, temperature, turbidity versus depth casts along with glacial runoff estimation from Rink and Store glaciers, two major marine outlets draining the western sector of the GrIS during 2009 and 2010. We characterise the main water bodies present and interpret their interaction with their respective calving fronts. We identify two distinct processes of ice-ocean interaction which have distinct spatial and temporal footprints: (1) homogenous free convective melting which occurs across the calving front where AW is in direct contact with the ice mass, and (2) localised upwelling-driven melt by turbulent subglacial runoff mixing with fjord water which occurs at distinct injection points across the calving front. Throughout the study, AW at 2.8 ± 0.2 °C was consistently observed in contact with both glaciers below 450 m depth, yielding homogenous, free convective submarine melting up to ~200 m depth. Above this bottom layer, multiple interactions are identified, primarily controlled by the rate of subglacial fresh-water discharge which results in localised and discrete upwelling plumes. In the record melt year of 2010, the Store Glacier calving face was dominated by these runoff-driven plumes which led to a highly crenulated frontal geometry characterised by large embayments at the subglacial portals separated by headlands which are dominated by calving. Rink Glacier, which is significantly deeper than Store has a larger proportion of its submerged calving face exposed to AW, which results in a uniform, relatively flat overall frontal geometry.

  11. Adjustments of a global Finite-Element Sea Ice Ocean Model configuration to improve the general ocean circulation in the North Pacific and its marginal seas. (United States)

    Scholz, Patrick; Lohmann, Gerrit


    The sub-Arctic oceans like the Sea of Okhotsk, the Bering Sea, the Labrador Sea or the Greenland- Irminger-Norwegian (GIN) Sea react particularly sensitive to global climate changes and have the potential to reversely regulate climate change by CO2 uptake in the other areas of the world. So far, the natural processes in the Arctic and Subarctic system, especially over the Pacific realm, remain poorly understood in terms of numerical modeling. As such, in this study we focus on the North Pacific and its adjacent marginal seas (e.g. the Sea of Okhotsk, the Bering Sea and the Sea of Japan), which have nowadays a significant role in the climate system of the Northwest Pacific by influencing the atmospheric and oceanic circulation as well as the hydrology of the Pacific water masses. The Sea of Okhotsk, in particular, is characterized by a highly dynamical sea-ice coverage, where, in autumn and winter, due to massive sea ice formation and brine rejection, the Sea of Okhotsk Intermediate Water (SOIW) is formed which contributes to the mid-depth (500-1000m) water layer of the North Pacific known as newly formed North Pacific Intermediate Water (NPIW). By employing a Finite-Element Sea-Ice Ocean Model (FESOM), in a global configuration, but with high resolution over the marginal seas of the Northwest Pacific Ocean ( 7 km), we tested different meshes and forcing improvements to correct the general ocean circulation in the North Pacific realm towards a more realistic pattern. By using different forcing data (e.g. CORE2, ERA-40/interim, CCMP-correction), adapting the mesh resolutions in the tropical and subtropical North Pacific and changing the bathymetry over important inflow straits (e.g. Amukta Passage, Kruzenstern Strait), we show that the better results are obtained (when compared with observational data) via a combination of CCMP corrected COREv2 forcing with increased resolution in the pathway of the Kuroshio Extension Current and Northern Equatorial Current.

  12. Ice and ocean velocity in the Arctic marginal ice zone: Ice roughness and momentum transfer

    Directory of Open Access Journals (Sweden)

    Sylvia T. Cole


    Full Text Available The interplay between sea ice concentration, sea ice roughness, ocean stratification, and momentum transfer to the ice and ocean is subject to seasonal and decadal variations that are crucial to understanding the present and future air-ice-ocean system in the Arctic. In this study, continuous observations in the Canada Basin from March through December 2014 were used to investigate spatial differences and temporal changes in under-ice roughness and momentum transfer as the ice cover evolved seasonally. Observations of wind, ice, and ocean properties from four clusters of drifting instrument systems were complemented by direct drill-hole measurements and instrumented overhead flights by NASA operation IceBridge in March, as well as satellite remote sensing imagery about the instrument clusters. Spatially, directly estimated ice-ocean drag coefficients varied by a factor of three with rougher ice associated with smaller multi-year ice floe sizes embedded within the first-year-ice/multi-year-ice conglomerate. Temporal differences in the ice-ocean drag coefficient of 20–30% were observed prior to the mixed layer shoaling in summer and were associated with ice concentrations falling below 100%. The ice-ocean drag coefficient parameterization was found to be invalid in September with low ice concentrations and small ice floe sizes. Maximum momentum transfer to the ice occurred for moderate ice concentrations, and transfer to the ocean for the lowest ice concentrations and shallowest stratification. Wind work and ocean work on the ice were the dominant terms in the kinetic energy budget of the ice throughout the melt season, consistent with free drift conditions. Overall, ice topography, ice concentration, and the shallow summer mixed layer all influenced mixed layer currents and the transfer of momentum within the air-ice-ocean system. The observed changes in momentum transfer show that care must be taken to determine appropriate parameterizations

  13. Observational Evidence of a Hemispheric-wide Ice-ocean Albedo Feedback Effect on Antarctic Sea-ice Decay (United States)

    Nihashi, Sohey; Cavalieri, Donald J.


    The effect of ice-ocean albedo feedback (a kind of ice-albedo feedback) on sea-ice decay is demonstrated over the Antarctic sea-ice zone from an analysis of satellite-derived hemispheric sea ice concentration and European Centre for Medium-Range Weather Forecasts (ERA-40) atmospheric data for the period 1979-2001. Sea ice concentration in December (time of most active melt) correlates better with the meridional component of the wind-forced ice drift (MID) in November (beginning of the melt season) than the MID in December. This 1 month lagged correlation is observed in most of the Antarctic sea-ice covered ocean. Daily time series of ice , concentration show that the ice concentration anomaly increases toward the time of maximum sea-ice melt. These findings can be explained by the following positive feedback effect: once ice concentration decreases (increases) at the beginning of the melt season, solar heating of the upper ocean through the increased (decreased) open water fraction is enhanced (reduced), leading to (suppressing) a further decrease in ice concentration by the oceanic heat. Results obtained fi-om a simple ice-ocean coupled model also support our interpretation of the observational results. This positive feedback mechanism explains in part the large interannual variability of the sea-ice cover in summer.

  14. Arctic Ocean surface geostrophic circulation 2003-2014 (United States)

    Armitage, Thomas W. K.; Bacon, Sheldon; Ridout, Andy L.; Petty, Alek A.; Wolbach, Steven; Tsamados, Michel


    Monitoring the surface circulation of the ice-covered Arctic Ocean is generally limited in space, time or both. We present a new 12-year record of geostrophic currents at monthly resolution in the ice-covered and ice-free Arctic Ocean derived from satellite radar altimetry and characterise their seasonal to decadal variability from 2003 to 2014, a period of rapid environmental change in the Arctic. Geostrophic currents around the Arctic basin increased in the late 2000s, with the largest increases observed in summer. Currents in the southeastern Beaufort Gyre accelerated in late 2007 with higher current speeds sustained until 2011, after which they decreased to speeds representative of the period 2003-2006. The strength of the northwestward current in the southwest Beaufort Gyre more than doubled between 2003 and 2014. This pattern of changing currents is linked to shifting of the gyre circulation to the northwest during the time period. The Beaufort Gyre circulation and Fram Strait current are strongest in winter, modulated by the seasonal strength of the atmospheric circulation. We find high eddy kinetic energy (EKE) congruent with features of the seafloor bathymetry that are greater in winter than summer, and estimates of EKE and eddy diffusivity in the Beaufort Sea are consistent with those predicted from theoretical considerations. The variability of Arctic Ocean geostrophic circulation highlights the interplay between seasonally variable atmospheric forcing and ice conditions, on a backdrop of long-term changes to the Arctic sea ice-ocean system. Studies point to various mechanisms influencing the observed increase in Arctic Ocean surface stress, and hence geostrophic currents, in the 2000s - e.g. decreased ice concentration/thickness, changing atmospheric forcing, changing ice pack morphology; however, more work is needed to refine the representation of atmosphere-ice-ocean coupling in models before we can fully attribute causality to these increases.

  15. Planetary Ice-Oceans: Numerical Modeling Study of Ice-Shell Growth in Convecting Two-Phase Systems (United States)

    Allu Peddinti, Divya; McNamara, Allen


    Several icy bodies in the Solar system such as the icy moons Europa and Enceladus exhibit signs of subsurface oceans underneath an ice-shell. For Europa, the geologically young surface, the presence of surface features and the aligned surface chemistry pose interesting questions about formation of the ice-shell and its interaction with the ocean below. This also ties in with its astrobiological potential and implications for similar ice-ocean systems elsewhere in the cosmos. The overall thickness of the H2O layer on Europa is estimated to be 100-150 km while the thickness of the ice-shell is debated. Additionally, Europa is subject to tidal heating due to interaction with Jupiter's immense gravity field. It is of interest to understand how the ice-shell thickness varies in the presence of tidal internal heating and the localization of heating in different regions of the ice-shell. Thus this study aims to determine the effect of tidal internal heating on the growth rate of the ice-shell over time. We perform geodynamic modeling of the ice-ocean system in order to understand how the ice-shell thickness changes with time. The convection code employs the ice Ih-water phase diagram in order to model the two-phase convecting ice-ocean system. All the models begin from an initial warm thick ocean that cools from the top. The numerical experiments analyze three cases: case 1 with no tidal internal heating in the system, case 2 with constant tidal internal heating in the ice and case 3 with viscosity-dependent tidal internal heating in the ice. We track the ice-shell thickness as a function of time as the system cools. Modeling results so far have identified that the shell growth rate changes substantially at a point in time that coincides with a change in the planform of ice-convection cells. Additionally, the velocity vs depth plots indicate a shift from a conduction dominant to a convection dominant ice regime. We compare the three different cases to provide a

  16. Astronomical Ice: The Effects of Treating Ice as a Porous Media on the Dynamics and Evolution of Extraterrestrial Ice-Ocean Environments (United States)

    Buffo, J.; Schmidt, B. E.


    With the prevalence of water and ice rich environments in the solar system, and likely the universe, becoming more apparent, understanding the evolutionary dynamics and physical processes of such locales is of great importance. Piqued interest arises from the understanding that the persistence of all known life depends on the presence of liquid water. As in situ investigation is currently infeasible, accurate numerical modeling is the best technique to demystify these environments. We will discuss an evolving model of ice-ocean interaction aimed at realistically describing the behavior of the ice-ocean interface by treating basal ice as a porous media, and its possible implications on the formation of astrobiological niches. Treating ice as a porous media drastically affects the thermodynamic properties it exhibits. Thus inclusion of this phenomenon is critical in accurately representing the dynamics and evolution of all ice-ocean environments. This model utilizes equations that describe the dynamics of sea ice when it is treated as a porous media (Hunke et. al. 2011), coupled with a basal melt and accretion model (Holland and Jenkins 1999). Combined, these two models produce the most accurate description of the processes occurring at the base of terrestrial sea ice and ice shelves, capable of resolving variations within the ice due to environmental pressures. While these models were designed for application to terrestrial environments, the physics occurring at any ice-water interface is identical, and these models can be used to represent the evolution of a variety of icy astronomical bodies. As terrestrial ice shelves provide a close analog to planetary ice-ocean environments, we truth test the models validity against observations of ice shelves. We apply this model to the ice-ocean interface of the icy Galilean moon Europa. We include profiles of temperature, salinity, solid fraction, and Darcy velocity, as well as temporally and spatially varying melt and

  17. The Arctic Report Card: Communicating the State of the Rapidly Changing Arctic to a Diverse Audience via the Worldwide Web (United States)

    Jeffries, M. O.; Richter-Menge, J.; Overland, J. E.; Soreide, N. N.


    Rapid change is occurring throughout the Arctic environmental system. The goal of the Arctic Report Card is to communicate the nature of the many changes to a diverse audience via the Worldwide Web. First published in 2006, the Arctic Report Card is a peer-reviewed publication containing clear, reliable and concise scientific information on the current state of the Arctic environment relative to observational records. Available only online, it is intended to be an authoritative source for scientists, teachers, students, decision-makers, policy-makers and the general public interested in the Arctic environment and science. The Arctic Report Card is organized into five sections: Atmosphere; Sea Ice & Ocean; Marine Ecosystem; Terrestrial Ecosystem; Terrestrial Cryosphere. Arctic Report Card 2012, the sixth annual update, comprised 20 essays on physical and biological topics prepared by an international team of 141 scientists from 15 different countries. For those who want a quick summary, the Arctic Report Card home page provides highlights of key events and findings, and a short video that is also available on YouTube. The release of the Report Card each autumn is preceded by a NOAA press release followed by a press conference, when the Web site is made public. The release of Arctic Report Card 2012 at an AGU Fall Meeting press conference on 5 December 2012 was subsequently reported by leading media organizations. The NOAA Arctic Web site, of which the Report Card is a part, is consistently at the top of Google search results for the keyword 'arctic', and the Arctic Report Card Web site tops search results for keyword "arctic report" - pragmatic indications of a Web site's importance and popularity. As another indication of the Web site's impact, in December 2012, the month when the 2012 update was released, the Arctic Report Card Web site was accessed by 19,851 unique sites in 105 countries, and 4765 Web site URLs referred to the Arctic Report Card. The 2012 Arctic

  18. Towards improved estimation of the dynamic topography and ocean circulation in the high latitude and arctic ocean: The importance of GOCE

    DEFF Research Database (Denmark)

    Johannessen, J. A.; Raj, R. P.; Nilsen, J. E. Ø.


    . In this respect this study combines in-situ hydrographical data, surface drifter data and direct current meter measurements, with coupled sea ice - ocean models, radar altimeter data and the latest GOCE-based geoid in order to estimate and assess the quality, usefulness and validity of the new GOCE derived mean...... dynamic topography for studies of the ocean circulation and transport estimates in the Nordic Seas and Arctic Ocean....

  19. Simulation of Climatic Changes in the Arctic and North Atlantic During Recent Decades (United States)

    Hakkinen, Sirpa; Koblinsky, Chester J. (Technical Monitor)


    The interactions of the atmosphere and ice-ocean system in the Arctic will be studied using a coupled ice-ocean model which will also use ice drift derived from microwave observations as forcing. We especially search for linkages between the recent large climatic shifts in the Arctic Ocean and atmosphere for which period we also have microwave sea ice data. The coupled model area covers the whole N. Atlantic thus interactions between the lower latitudes are also investigated because we anticipate that the same large scale atmospheric patterns which dominate the midlatitudes extend their influence on the Arctic. The model hindcast for 1951-1993 shows clear decadal variability in the leading modes of ocean circulation. No specific low-freq modes are expected for the ice drift because its spectrum is white. However, the ice drift exhibits two see-saw patterns in response to the leading atmospheric circulation mode ('Arctic Oscillation'), one of them is the well-known out of phase relationship between Baffin Bay and Barents-Kara Seas, the other one is between Siberian shelf and Alaskan Coast (Hakkinen and Geiger, 2000).

  20. Evaluation of Arctic Sea Ice Thickness Simulated by Arctic Ocean Model Intercomparison Project Models (United States)

    Johnson, Mark; Proshuntinsky, Andrew; Aksenov, Yevgeny; Nguyen, An T.; Lindsay, Ron; Haas, Christian; Zhang, Jinlun; Diansky, Nikolay; Kwok, Ron; Maslowski, Wieslaw; hide


    Six Arctic Ocean Model Intercomparison Project model simulations are compared with estimates of sea ice thickness derived from pan-Arctic satellite freeboard measurements (2004-2008); airborne electromagnetic measurements (2001-2009); ice draft data from moored instruments in Fram Strait, the Greenland Sea, and the Beaufort Sea (1992-2008) and from submarines (1975-2000); and drill hole data from the Arctic basin, Laptev, and East Siberian marginal seas (1982-1986) and coastal stations (1998-2009). Despite an assessment of six models that differ in numerical methods, resolution, domain, forcing, and boundary conditions, the models generally overestimate the thickness of measured ice thinner than approximately 2 mand underestimate the thickness of ice measured thicker than about approximately 2m. In the regions of flat immobile landfast ice (shallow Siberian Seas with depths less than 25-30 m), the models generally overestimate both the total observed sea ice thickness and rates of September and October ice growth from observations by more than 4 times and more than one standard deviation, respectively. The models do not reproduce conditions of fast ice formation and growth. Instead, the modeled fast ice is replaced with pack ice which drifts, generating ridges of increasing ice thickness, in addition to thermodynamic ice growth. Considering all observational data sets, the better correlations and smaller differences from observations are from the Estimating the Circulation and Climate of the Ocean, Phase II and Pan-Arctic Ice Ocean Modeling and Assimilation System models.

  1. Arctic decadal variability: An auto-oscillatory system of heat and fresh water exchange (United States)

    Dukhovskoy, Dmitry S.; Johnson, Mark A.; Proshutinsky, Andrey


    This paper presents a mechanism of decadal variability in the Artic Ocean-GIN Sea (Greenland, Iceland and Norwegian Seas) atmosphere-ice-ocean system. We hypothesize that Arctic variability is regulated by heat and freshwater exchange between the Arctic Ocean and the GIN Sea. The interaction between basins is weak during anticyclonic circulation regimes (low AO/NAO) and strong during cyclonic circulation regimes (high AO/NAO). Regime shifts are controlled by the system itself through oceanic and atmospheric gradients (dynamic height and surface air temperature) that increase during the anticyclonic regime and decrease during the cyclonic regime. This conceptual mechanism for Arctic decadal variability has been reproduced in a model experiment. Both model results and observational data support the suggested mechanism.

  2. Simulating Baltic Sea climate for the period 1902-1998 with the Rossby Centre coupled ice-ocean model

    Energy Technology Data Exchange (ETDEWEB)

    Meier, H.E. Markus [Swedish Meteorological and Hydrological Inst., Rossby Centre, Norrkoeping (Sweden); Kauker, Frank [Alfred Wegener Inst. for Polar and Marine Research, Bremerhaven (Germany)


    Hindcast simulations for the period 1902-1998 have been performed using a 3D coupled ice-ocean model for the Baltic Sea. Daily sea level observations in Kattegat, monthly basin-wide discharge data, and reconstructed atmospheric surface data have been used to force the Baltic Sea model. The reconstruction utilizes a statistical model to calculate daily sea level pressure and monthly surface air temperature, dew point temperature, precipitation, and cloud cover fields on a 1 deg x 1 deg regular horizontal grid for the Baltic Sea region. An improved turbulence scheme has been implemented into the Baltic Sea model to simulate saltwater inflows realistically. The results are validated against available observational datasets for sea level, salinity, saltwater inflow, volume transport, and sea ice. In addition, a comparison is performed with simulations for the period 1980-1993 using 3-hourly gridded atmospheric observations from synoptic stations. It is shown that the results of the Baltic Sea model forced with the reconstructed data are satisfactory. Sensitivity experiments have been performed to explore the impact of internal mixing, fresh and saltwater inflows, sea ice, and the sea level in Kattegat on the salinity of the Baltic Sea. It is found that the decadal variability of mean salinity is explained partly by decadal volume variations of the accumulated freshwater inflow from river runoff and net precipitation and partly by decadal variations of the large-scale sea level pressure over Scandinavia. During the last century two exceptionally long stagnation periods are found, the 1920s to the 1930s and the 1980s to the mid 1990s. During these periods precipitation, runoff and westerly winds were stronger than normal. Stronger westerly winds caused increased eastward surface-layer transports. Consequently, the mean eastward lower layer transports through the Stolpe Channel is reduced. The response time scale of the Baltic Sea is of the order of 30-40 years. The large

  3. Ice at the Interface: Atmosphere-Ice-Ocean Boundary Layer Processes and Their Role in Polar Change---Workshop Report

    Energy Technology Data Exchange (ETDEWEB)

    Hunke, Elizabeth C. [Los Alamos National Laboratory


    The atmosphere-ocean boundary layer in which sea ice resides includes many complex processes that require a more realistic treatment in GCMs, particularly as models move toward full earth system descriptions. The primary purpose of the workshop was to define and discuss such coupled processes from observational and modeling points of view, including insight from both the Arctic and Antarctic systems. The workshop met each of its overarching goals, including fostering collaboration among experimentalists, theorists and modelers, proposing modeling strategies, and ascertaining data availability and needs. Several scientific themes emerged from the workshop, such as the importance of episodic or extreme events, precipitation, stratification above and below the ice, and the marginal ice zone, whose seasonal Arctic migrations now traverse more territory than in the past.

  4. Arctic geopolitics

    Energy Technology Data Exchange (ETDEWEB)

    Meyerhoff, H.A.; Meyerhoff, A.A.


    The Arctic region is all of the earth north of 60/sup 0/N Lat.--an area of 14 million sq miles (36.4 million sq km), or 7% of the world's surface area and 14% of its land area. Russia fronts 52% of the Arctic Ocean and has jurisdiction over 70% of the continental shelves. Moreover, of the approx. 256 million persons living in the 6 Arctic nations, 244 million are citizens of the USSR. It is plain from these statistics that Russia's position in the arctic is not just predominant; it is overwhelming. The same statement is true of the mineral resources of the arctic. Although not well explored, Russia's nonhydrocarbon mineral wealth probably is proportionate to her arctic area. Russia's hydrocarbon reserves are far out of proportion to the area controlled; for example, proved plus probable reserves in the W. Siberian Basin alone are double those of the entire U.S. Control of the arctic, therefore, is vital to Russia, but despite her much greater population, she does not yet have manpower to develop and control the arctic. Development of arctic resources will take place best in an atmosphere of international peace and cooperation. (97 refs.)

  5. Influence of Sea Ice on Arctic Marine Sulfur Biogeochemistry in the Community Climate System Model

    Energy Technology Data Exchange (ETDEWEB)

    Deal, Clara [Univ. of Alaska, Fairbanks, AL (United States); Jin, Meibing [Univ. of Alaska, Fairbanks, AL (United States)


    Global climate models (GCMs) have not effectively considered how responses of arctic marine ecosystems to a warming climate will influence the global climate system. A key response of arctic marine ecosystems that may substantially influence energy exchange in the Arctic is a change in dimethylsulfide (DMS) emissions, because DMS emissions influence cloud albedo. This response is closely tied to sea ice through its impacts on marine ecosystem carbon and sulfur cycling, and the ice-albedo feedback implicated in accelerated arctic warming. To reduce the uncertainty in predictions from coupled climate simulations, important model components of the climate system, such as feedbacks between arctic marine biogeochemistry and climate, need to be reasonably and realistically modeled. This research first involved model development to improve the representation of marine sulfur biogeochemistry simulations to understand/diagnose the control of sea-ice-related processes on the variability of DMS dynamics. This study will help build GCM predictions that quantify the relative current and possible future influences of arctic marine ecosystems on the global climate system. Our overall research objective was to improve arctic marine biogeochemistry in the Community Climate System Model (CCSM, now CESM). Working closely with the Climate Ocean Sea Ice Model (COSIM) team at Los Alamos National Laboratory (LANL), we added 1 sea-ice algae and arctic DMS production and related biogeochemistry to the global Parallel Ocean Program model (POP) coupled to the LANL sea ice model (CICE). Both CICE and POP are core components of CESM. Our specific research objectives were: 1) Develop a state-of-the-art ice-ocean DMS model for application in climate models, using observations to constrain the most crucial parameters; 2) Improve the global marine sulfur model used in CESM by including DMS biogeochemistry in the Arctic; and 3) Assess how sea ice influences DMS dynamics in the arctic marine

  6. Arctic Newcomers

    DEFF Research Database (Denmark)

    Tonami, Aki


    Interest in the Arctic region and its economic potential in Japan, South Korea and Singapore was slow to develop but is now rapidly growing. All three countries have in recent years accelerated their engagement with Arctic states, laying the institutional frameworks needed to better understand an...

  7. Arctic methane

    NARCIS (Netherlands)

    Dyupina, E.; Amstel, van A.R.


    What are the risks of a runaway greenhouse effect from methane release from hydrates in the Arctic? In January 2013, a dramatic increase of methane concentration up to 2000 ppb has been measured over the Arctic north of Norway in the Barents Sea. The global average being 1750 ppb. It has been

  8. Biopolymers form a gelatinous microlayer at the air-sea interface when Arctic sea ice melts (United States)

    Galgani, Luisa; Piontek, Judith; Engel, Anja


    The interface layer between ocean and atmosphere is only a couple of micrometers thick but plays a critical role in climate relevant processes, including the air-sea exchange of gas and heat and the emission of primary organic aerosols (POA). Recent findings suggest that low-level cloud formation above the Arctic Ocean may be linked to organic polymers produced by marine microorganisms. Sea ice harbors high amounts of polymeric substances that are produced by cells growing within the sea-ice brine. Here, we report from a research cruise to the central Arctic Ocean in 2012. Our study shows that microbial polymers accumulate at the air-sea interface when the sea ice melts. Proteinaceous compounds represented the major fraction of polymers supporting the formation of a gelatinous interface microlayer and providing a hitherto unrecognized potential source of marine POA. Our study indicates a novel link between sea ice-ocean and atmosphere that may be sensitive to climate change.

  9. Biopolymers form a gelatinous microlayer at the air-sea interface when Arctic sea ice melts. (United States)

    Galgani, Luisa; Piontek, Judith; Engel, Anja


    The interface layer between ocean and atmosphere is only a couple of micrometers thick but plays a critical role in climate relevant processes, including the air-sea exchange of gas and heat and the emission of primary organic aerosols (POA). Recent findings suggest that low-level cloud formation above the Arctic Ocean may be linked to organic polymers produced by marine microorganisms. Sea ice harbors high amounts of polymeric substances that are produced by cells growing within the sea-ice brine. Here, we report from a research cruise to the central Arctic Ocean in 2012. Our study shows that microbial polymers accumulate at the air-sea interface when the sea ice melts. Proteinaceous compounds represented the major fraction of polymers supporting the formation of a gelatinous interface microlayer and providing a hitherto unrecognized potential source of marine POA. Our study indicates a novel link between sea ice-ocean and atmosphere that may be sensitive to climate change.

  10. On the Role of Arctic Sea Ice Deformations: An Evaluation of the Regional Arctic System Model Results with Observations. (United States)

    Osinski, Robert; Maslowski, Wieslaw; Roberts, Andrew


    The atmosphere - sea ice - ocean fluxes and their contribution to rapid changes in the Arctic system are not well understood and generally are not resolved by global climate models (GCMs). While many significant model refinements have been made in the recent past, including the representation of sea ice rheology, surface albedo and ice-albedo feedback, other processes such as sea ice deformations, still require further studies and model advancements. Of particular potential interest here are linear kinematic features (LKFs), which control winter air-sea heat exchange and affect buoyancy forces in the ocean. Their importance in Arctic climate change, especially under an increasing first-year ice cover, is yet to be determined and their simulation requires representation of processes currently at sub-grid scale of most GCMs. To address some of the GCM limitations and to better understand the role of LKFs in air-sea exchange we use the Regional Arctic System Model (RASM), which allows high spatio-temporal resolution and regional focus on the Arctic. RASM is a fully coupled regional climate model, developed to study dynamic and thermodynamic processes and their coupling across the atmosphere-sea ice-ocean interface. It consists of the Weather Research and Forecasting (WRF) atmospheric model, the Parallel Ocean Program (POP), the Community Ice Model (CICE) and the Variable Infiltration Capacity (VIC) land hydrology model. The sea ice component has been upgraded to the Los Alamos Community Ice Model version 5.1 (CICE5.1), which allows either Elastic-Viscous-Plastic (EVP) or a new anisotropic (EPA) rheology. RASM's domain is pan-Arctic, with the ocean and sea ice components configured at an eddy-permitting horizontal resolution of 1/12-degree as well as 1/48-degree, for limited simulations. The atmosphere and land model components are configured at 50-km grids. All the components are coupled at a 20-minute time step. Results from multiple RASM simulations are analyzed and

  11. Increasing winter conductive heat transfer in the Arctic sea-ice-covered areas: 1979–2014 (United States)

    Fan, Xieyu; Bi, Haibo; Wang, Yunhe; Fu, Min; Zhou, Xuan; Xu, Xiuli; Huang, Haijun


    Sea ice is a quite sensitive indicator in response to regional and global climate changes. Based on monthly mean Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) sea ice thickness fields, we computed the conductive heat flux (CHF) in the Arctic Ocean in the four winter months (November-February) for a long period of 36 years (1979-2014). The calculated results for each month manifest the increasing extension of the domain with high CHF values since 1979 till 2014. In 2014, regions of roughly 90% of the central Arctic Ocean have been dominated by the CHF values larger than 18 W m-2 (November-December) and 12 W m-2 (January-February), especially significant in the shelf seas around the Arctic Ocean. Moreover, the population distribution frequency (PDF) patterns of the CHF with time show gradually peak shifting toward increased CHF values. The spatiotemporal patterns in terms of the trends in sea ice thickness and other three geophysical parameters, surface air temperature (SAT), sea ice thickness (SIT), and CHF, are well coupled. This suggests that the thinner sea ice cover preconditions for the more oceanic heat loss into atmosphere (as suggested by increased CHF values), which probably contributes to warmer atmosphere which in turn in the long run will cause thinner ice cover. This represents a positive feedback mechanism of which the overall effects would amplify the Arctic climate changes.

  12. Sensitivity of palaeo-ice-stream retreat patterns to ice-ocean interactions and topography: a test of the marine ice sheet instability hypothesis (United States)

    Jamieson, S.; Vieli, A.; Livingstone, S. J.; O'Cofaigh, C.; Stokes, C. R.; Hillenbrand, C.


    The aim is to understand the long-term controls on marine ice stream retreat. Short-term observations combined with modelling are helping decipher the controls driving contemporary mass loss via dynamic thinning and grounding-line retreat. However, ice-stream response times are likely to be longer than the timescales for which contemporary observations are available. We therefore focus on century to millenial timescales by investigating the retreat of Marguerite Bay palaeo-ice stream in Antarctica after the LGM. Our approach is to use high-resolution mapping of glacial landforms on the sea floor to constrain a numerical ice stream model. Mapped positions of grounding-zone wedges indicate that the palaeo-ice stream paused multiple times during its rapid retreat over a bed that deepens inland. The geomorphic record not only questions the marine ice sheet instability hypothesis but also provides geometrical and dynamical constraints for retreat experiments using numerical ice stream models. To understand the controls on the retreat pattern in Marguerite Bay, we test the sensitivity of the ice stream to a range of forcing regimes using a 1-dimensional numerical flow-line model that incorporates basal, lateral and longitudinal stresses and a self-refining grid scheme. Ice-ocean interactions are incorporated via a fixed-length ice shelf, the inclusion of an ice-ocean boundary condition and the calculation of ocean-driven melt. We test modelled retreat sensitivity to a range of external forcing patterns including sea-level, temperature, accumulation and ocean-driven melt. In addition, the importance of the topographic setting of the ice drainage basin is also examined. We find that the modelled ice stream naturally re-creates the pauses observed in the geomorphic record and that the pattern of palaeo-grounding-line retreat in Marguerite Bay can only be achieved within the chronological timeframe by including ocean-driven melt. Sensitivity tests indicate that the

  13. Waves in Ice Forecasting for Arctic Operators (United States)

    Dumont, D.; Williams, T.; Bennetts, L.


    Sea ice cover is becoming increasingly weak and fragmented during the summer in the Arctic Ocean. This presents new opportunities for offshore engineering activities and shipping routes. However, operational forecasting models do not include waves in the partially ice-covered ocean, or their impact on the ice cover, which severely compromises the safety of potential human activities in these regions. Wave-ice interactions are composed of two coupled processes. First, ice floes cause wave energy to attenuate. Second, wave motion imposes strains on the ice cover, which can fracture the ice into small floes. We have developed the first model that incorporates both wave attenuation and ice fracture. The model predicts the evolution of the wave spectrum in the ice-covered ocean and the floe size distribution in the initial 10s to 100s of kilometers of ice-covered ocean, where waves control the maximum floe size allowable. The model is currently being nested in areas of operational interest in a pan-Artic ice-ocean model.

  14. Seasonal-to-Decadal Predictions of Arctic Sea Ice: Challenges and Strategies (United States)

    Richter-Menge, J.; Walsh, J. E.; Thomas, K.


    Arctic sea ice plays a number of important roles in moderating global climate and influencing oceanic and atmospheric circulation. The recent dramatic changes in the thickness and extent of the Arctic sea ice cover, which can be linked to the warming climate, are well-documented. Such changes in Arctic sea ice have various direct and indirect scientific, technological, and societal impacts such as the planning of new shipping ports, oil and gas exploration, increased marine transportation, as well as ecological changes. Currently, our limited understanding of the coupled and complex interactions between Arctic sea ice, oceans, and atmosphere hinders our ability to predict the rate and magnitude of future change. In addition, while a number of efforts are underway to better understand the role of Arctic sea ice in the broader context of the Arctic climate system, and to forecast sea ice, there is also a need to better understand the role that sea ice plays beyond the polar region. A 2012 National Research Council report, "Seasonal-to-Decadal Predictions of Arctic Sea Ice: Challenges and Strategies", explores current major challenges in sea ice prediction and identifies new methods, observations, and technologies that might advance seasonal-to-decadal sea ice predictive capabilities through improved understanding of the Arctic system. Based heavily on information generated at a large community workshop, the report examines current observations and modeling efforts of sea ice, and identifies (but does not prioritize) areas of research and technology advances needed to better understand current and future changes. The report places a particular emphasis on seasonal-to-decadal timescales.

  15. Arctic Ocean geostrophic circulation 2003-2014 (United States)

    Armitage, T.; Bacon, S.; Ridout, A.; Tsamados, M.


    We present a 12-year record of geostrophic currents in the ice-covered and ice-free Arctic Ocean derived from Envisat and CryoSat-2 radar altimetry and examine their seasonal to decadal variability. Geostrophic currents across the Arctic Ocean increased in the late 2000s and, in particular, the Beaufort gyre circulation accelerated significantly in autumn 2007. At this time, the Beaufort Sea saw strong and persistent anticylonic atmospheric circulation anomalies, a record low sea ice extent and an associated dramatic loss of multiyear sea ice, and a consequently thinner and more mobile autumn ice pack. These factors combined to bring about high ocean surface stress, strong Ekman convergence, and anomalously strong geostrophic current speeds in the south-eastern Beaufort Sea in the period 2003 to 2014. Current speeds in the south-eastern Beaufort Sea remained higher until 2011, after which they decreased to speeds representative of the period 2003-2006. Meanwhile, there was an almost three-fold increase in the westward current at the western periphery of the Beaufort gyre between 2003 and 2014. This likely played a more important role in advecting old ice from the southern Beaufort Sea to the Siberian shelf seas where it is more easily melted in summer compared to ice that is re-circulated in the Beaufort gyre. The southward current through Fram Start increased between 2003 and 2012 before slowing somewhat by the end of the time period. Seasonal fields of eddy kinetic energy reveal high eddy activity congruent with the Chukchi plateau and Northwind Ridge. Both the Beaufort gyre circulation and the southward current through Fram Strait are strongest in autumn and winter, modulated by the seasonal strength of the Beaufort Sea high and Icelandic low pressure systems. Our results point to a variable and changing role of ocean currents in the coupled sea ice-ocean momentum balance.

  16. Arctic Security

    DEFF Research Database (Denmark)

    Wang, Nils


    The inclusion of China, India, Japan, Singapore and Italy as permanent observers in the Arctic Council has increased the international status of this forum significantly. This chapter aims to explain the background for the increased international interest in the Arctic region through an analysis...... of the general security situation and to identify both the explicit and the implicit agendas of the primary state actors. The region contains all the ingredients for confrontation and conflict but the economical potential for all the parties concerned creates a general interest in dialogue and cooperation...

  17. Arctic Sea Ice Thickness Distribution as an Indicator of Arctic Climate Change - Synthesis of Model Results and Observations (United States)

    Maslowski, Wieslaw; Clement Kinney, Jaclyn; Jakacki, Jaromir; Osinski, Robert; Zwally, Jay


    The Arctic region is an integral part of the Earth's climate system through its influence on global surface energy and moisture fluxes and on atmospheric and oceanic circulation. Within the Arctic, its sea ice cover is possibly the most sensitive indicator of the polar amplified global warming and of the state of Arctic climate system as a whole. Hence changes in Arctic climate and the decline of multi-year sea ice cover have significant ramifications to the entire pan-Arctic region and beyond. Having the recorded average global surface temperature about 0.54°C (0.96°F) above the 20th Century average the decade of 2000-2009 has been the warmest of the 130-year record, with the maximum positive temperatures anomalies in the northern high latitude regions. Satellite records of the Arctic sea ice show a decreasing and accelerating trend in ice extent and concentration since the late 1979, as a result of the global warming. More importantly there is growing evidence that the Arctic sea ice thickness and volume have been decreasing at even faster rate. This means that our knowledge of the Arctic sea ice melt might be significantly biased due to the interpretation of 2-dimensional sea ice extent / concentration records only instead of ice thickness and volume. The rates of recent ice thickness and volume melt derived from our pan-Arctic coupled ice-ocean model results combined with recent remotely sensed data suggest an accelerating negative trend. This trend is robust and lends credence to the postulation that the Arctic not only might but it is likely to be ice-free during the summer in the near future. However, global climate models vary widely in their predictions of warming and the rate of Arctic ice melt, suggesting it may take anywhere from a couple of decades to more than a century to melt most of the summer sea ice cover. Also many regional models are limited in their representation of the rapid Arctic sea ice thinning and volume loss. The inability of models

  18. Arctic Insecurity: Avoiding Conflict (United States)


    traditional route.11 The Arctic shipping routes are an average of 40% shorter than traditional Mediterranean routes.12...Arctic biodiversity , and communicate the findings to the governments and residents of the Arctic), 4) Emergency Prevention, Preparedness and Response

  19. Does Arctic sea ice reduction foster shelf-basin exchange? (United States)

    Ivanov, Vladimir; Watanabe, Eiji


    The recent shift in Arctic ice conditions from prevailing multi-year ice to first-year ice will presumably intensify fall-winter sea ice freezing and the associated salt flux to the underlying water column. Here, we conduct a dual modeling study whose results suggest that the predicted catastrophic consequences for the global thermohaline circulation (THC), as a result of the disappearance of Arctic sea ice, may not necessarily occur. In a warmer climate, the substantial fraction of dense water feeding the Greenland-Scotland overflow may form on Arctic shelves and cascade to the deep basin, thus replenishing dense water, which currently forms through open ocean convection in the sub-Arctic seas. We have used a simplified model for estimating how increased ice production influences shelf-basin exchange associated with dense water cascading. We have carried out case studies in two regions of the Arctic Ocean where cascading was observed in the past. The baseline range of buoyancy-forcing derived from the columnar ice formation was calculated as part of a 30-year experiment of the pan-Arctic coupled ice-ocean general circulation model (GCM). The GCM results indicate that mechanical sea ice divergence associated with lateral advection accounts for a significant part of the interannual variations in sea ice thermal production in the coastal polynya regions. This forcing was then rectified by taking into account sub-grid processes and used in a regional model with analytically prescribed bottom topography and vertical stratification in order to examine specific cascading conditions in the Pacific and Atlantic sectors of the Arctic Ocean. Our results demonstrate that the consequences of enhanced ice formation depend on geographical location and shelf-basin bathymetry. In the Pacific sector, strong density stratification in slope waters impedes noticeable deepening of shelf-origin water, even for the strongest forcing applied. In the Atlantic sector, a 1.5x increase of

  20. Turbulence and heat flux observations in the Arctic north of Svalbard (United States)

    Meyer, Amelie; Sundfjord, Arild; Fer, Ilker; Smedsrud, Lars Henrik


    Heat fluxes and mixing between the ocean and the sea ice in the Arctic is fundamental to understanding the new first year sea ice regime and consequences for regional and global ocean circulation. Here we present observations collected between January and June 2015 during the Norwegian Young sea Ice (N-ICE2015) campaign in the Arctic Ocean north of Svalbard. In January 2015, the Norwegian research vessel Lance was frozen into the ice at 83o.3N 21.5oE. Oceanographic, atmospheric, sea ice, snow and biological data were collected above, on, and below the ice using R/V Lance as the base for the ice camp that was drifting south towards the Fram Strait. Over the following six months, four different drifts took place in the same area, from the Nansen Basin, through the Marginal Ice Zone, to the open ocean. Throughout the drifts, the oceanography team collected turbulence measurements to estimate mixing, heat, salt, and momentum fluxes in the ice-ocean boundary layer and between the sub-surface warm Atlantic Water layer and the ice-ocean boundary layer close to freezing point. Water tracer data was collected to map water mass properties, and the distribution of the Atlantic Water inflow. Here we present 600 under-ice microstructure profiles spanning five months, from the deep Nansen Basin to the Yermak Plateau. During this period, several large atmospheric storms took place, forcing a fast drift of the ice camp. Tides were weak in the Nansen Basin and strong on the Yermak Plateau. We investigate vertical heat fluxes between the Atlantic Water layer and the surface mixed layer. Variations in mixing and heat fluxes are interpreted in terms of atmospheric forcing and regional topography.

  1. Aircraft Anomaly Prognostics Project (United States)

    National Aeronautics and Space Administration — Ridgetop Group will leverage its proven Electromechanical Actuator (EMA) prognostics methodology to develop an advanced model-based actuator prognostic reasoner...

  2. Recontinentalizing Canada: Arctic Ice’s Liquid Modernity and the Imagining of a Canadian Archipelago

    Directory of Open Access Journals (Sweden)

    Phillip Vannini


    Full Text Available Studying mobile actor networks of moving people, objects, images, and discourses, in conjunction with changing time-spaces, offers a unique opportunity to understand important, and yet relatively neglected, “relational material” dynamics of mobility. A key example of this phenomenon is the recontinentalization of Canada amidst dramatically changing articulations of the meanings and boundaries of the Canadian land-ice-ocean mass. A notable reason why Canada is being re-articulated in current times is the extensiveness of Arctic thawing. The reconfiguration of space and “motility” options in the Arctic constitutes an example of how “materiality and sociality produce themselves together.” In this paper we examine the possibilities and risks connected to this recontinentalization of Canada’s North. In exploring the past, present, and immediate future of this setting, we advance the paradigmatic view that Canada’s changing Arctic is the key element in a process of transformation of Canada into a peninsular body encompassed within a larger archipelagic entity: a place more intimately attuned to its immense (and growing coastal and insular routes.

  3. SONARC: A Sea Ice Monitoring and Forecasting System to Support Safe Operations and Navigation in Arctic Seas (United States)

    Stephenson, S. R.; Babiker, M.; Sandven, S.; Muckenhuber, S.; Korosov, A.; Bobylev, L.; Vesman, A.; Mushta, A.; Demchev, D.; Volkov, V.; Smirnov, K.; Hamre, T.


    Sea ice monitoring and forecasting systems are important tools for minimizing accident risk and environmental impacts of Arctic maritime operations. Satellite data such as synthetic aperture radar (SAR), combined with atmosphere-ice-ocean forecasting models, navigation models and automatic identification system (AIS) transponder data from ships are essential components of such systems. Here we present first results from the SONARC project (project term: 2015-2017), an international multidisciplinary effort to develop novel and complementary ice monitoring and forecasting systems for vessels and offshore platforms in the Arctic. Automated classification methods (Zakhvatkina et al., 2012) are applied to Sentinel-1 dual-polarization SAR images from the Barents and Kara Sea region to identify ice types (e.g. multi-year ice, level first-year ice, deformed first-year ice, new/young ice, open water) and ridges. Short-term (1-3 days) ice drift forecasts are computed from SAR images using feature tracking and pattern tracking methods (Berg & Eriksson, 2014). Ice classification and drift forecast products are combined with ship positions based on AIS data from a selected period of 3-4 weeks to determine optimal vessel speed and routing in ice. Results illustrate the potential of high-resolution SAR data for near-real-time monitoring and forecasting of Arctic ice conditions. Over the next 3 years, SONARC findings will contribute new knowledge about sea ice in the Arctic while promoting safe and cost-effective shipping, domain awareness, resource management, and environmental protection.

  4. Primary Production and C Flow in the Chukchi Sea Land-Fast Ice-Ocean Ecosystem and Sensitivity to Environmental Factors (United States)

    Deal, C. J.; Jin, M.; Wang, J.; Whitledge, T. E.; Lee, S. H.


    The recent downward trend in Arctic sea ice extent and thickness is a compelling indicator of climate change. These changes in sea ice affect the arctic marine ecosystem, which may depend on sea ice algal primary production for over 50% of the fixed C in the permanently ice-covered Arctic (Gosselin et al., 1997) and up to 25% in the surrounding marginal seas (Kirst and Wiencke, 1995). Since land-fast ice is generally the most accessible of the four sea ice regimes (perennial pack ice, coastal zone - including fast ice, seasonal pack ice and marginal ice zone), and in its own right is important in terms of aereal extent, on-going environmental changes along the coast and a platform for significant biological activity, our research group has focused on time series observations in the land-fast ice near Barrow, Alaska over the last several years. We have utilized the resultant data and those available from other research groups to develop a 1-D marine ecosystem model from which we have constructed an organic C budget based on observations including ice algal biomass (chl a), phytoplankton biomass (chl a), POC, PON, indicators of zooplankton and ice meiofaunal grazing, nutrients, in situ carbon and nutrient uptake, temperature, salinity, ice thickness and snow cover. Through model sensitivity studies, we found that doubling of the initial nutrient concentrations has a significant impact on sea ice primary production, being roughly proportional. Also, a doubling of light (PAR) shifts the exponential accumulation of sea ice algal biomass ahead approximately one week. These model results provide evidence that changes in river discharge that alter nutrient concentrations, and changes in the light regime linked to ongoing environmental changes such as sediment loading, lessening sea ice thickness, and interannual variations in snow cover significantly impact the marine ecosystem. These influences may cascade through the marine ecosystem to affect the food web and hence

  5. The seasonal and inter-annual variability of sea-ice, ocean circulation and marine ecosystems in the Barents Sea: model results against satellite data (United States)

    Dvornikov, Anton; Sein, Dmitry; Ryabchenko, Vladimir; Gorchakov, Victor; Pugalova, Svetlana


    This study is aimed at modelling the seasonal and inter-annual variability of sea-ice, ocean circulation and marine ecosystems in the Barents Sea in the modern period. Adequate description of marine ecosystems in the ice-covered seas crucially depends on the accuracy in determining of thicknesses of ice and snow on the sea surface which control penetrating photosynthetically active radiation under the ice. One of the few models of ice able to adequately reproduce the dynamics of sea ice is the sea ice model HELMI [1], containing 7 different categories of ice. This model has been imbedded into the Princeton Ocean Model. With this coupled model 2 runs for the period 1998-2007 were performed under different atmospheric forcing prescribed from NCEP/NCAR and ERA-40 archives. For prescribing conditions at the open boundary, all the necessary information about the horizontal velocity, level, temperature and salinity of the water, ice thickness and compactness was taken from the results of the global ocean general circulation model of the Max Planck Institute for Meteorology (Hamburg, Germany) MPIOM [2]. The resulting solution with NCEP forcing with a high accuracy simulates the seasonal and inter-annual variability of sea surface temperature (SST) estimated from MODIS data. The maximum difference between the calculated and satellite-derived SSTs (averaged over 4 selected areas of the Barents Sea) during the period 2000-2007 does not exceed 1.5 °C. Seasonal and inter-annual variations in the area of ice cover are also in good agreement with satellite-derived estimates. Pelagic ecosystem model developed in [3] has been coupled into the above hydrodynamic model and used to calculate the changes in the characteristics of marine ecosystems under NCEP forcing. Preliminarily the ecosystem model has been improved by introducing a parameterization of detritus deposition on the bottom and through the selection of optimal parameters for photosynthesis and zooplankton grazing

  6. Importance of Ocean Processes and Feedbacks with Sea Ice in Arctic Amplification (United States)

    Maslowski, Wieslaw; DiMaggio, Dominic; Lee, Younjoo; Osinski, Robert; Roberts, Andrew


    The Arctic is undergoing some of the most coordinated and rapid climatic changes currently occurring anywhere on Earth. While historical reconstructions from Earth System Models (ESMs) are in broad agreement with these changes, the rate of change in ESMs remains outpaced by observations. This is due to a combination of coarse resolution, inadequate parameterizations, under-represented processes and a limited knowledge of physical interactions. We hypothesize that these limitations are in part the result of an inadequate representation of critical high-latitude processes controlling the accumulation and distribution of sub-surface oceanic heat content and its interaction with the sea ice cover, especially in the western Arctic. Several CMIP5 models are evaluated using a skill metric that combines both variance and correlation between modeled and observed quantities. Models inadequately represent the upper ocean hydrology in the central Canada Basin, and the potentially important heat sources of the near-surface temperature maximum and Pacific Summer Water are missing. This is evidenced by the fact that the CMIP5 multi-model mean exhibits a cold temperature bias near the surface and a warm bias at intermediate depths. To identify the sensitivity of upper Arctic Ocean hydrography to physical processes and model configurations, a series of experiments are performed using the Regional Arctic System Model (RASM), a high-resolution, fully-coupled regional climate model. Analysis of RASM output suggests that surface momentum coupling (air-ice, ice-ocean, and air-ocean), brine-rejection parameterization, and model resolution, both horizontal and vertical, influence thermohaline structure down to 700 m. We argue that such improvements are needed in future CMIP-type models to advance their simulation and prediction of Arctic climate change.

  7. INTAROS: Development of an integrated Arctic observation system under Horizon 2020 (United States)

    Beszczynska-Möller, Agnieszka; Sandven, Stein; Sagen, Hanne


    INTAROS is a research and innovation action funded under the H2020-BG-09 call for the five-year period 2016-2021. INTAROS will develop an integrated Arctic Observation System (iAOS) by extending, improving and unifying existing systems in the different regions of the Arctic. INTAROS will have a strong multidisciplinary focus, with tools for integration of data from atmosphere, ocean, cryosphere and terrestrial sciences, provided by institutions in Europe, North America and Asia. Satellite earth observation (EO) data plays an increasingly important role in such observing systems, because the amount of EO data for observing the global climate and environment grows year by year. EO data will therefore be integrated into iAOS based on existing products and databases. In situ observing systems are much more limited due to logistical constraints and cost limitations. The sparseness of in situ data is therefore the largest gap in the overall observing system. INTAROS will assess strengths and weaknesses of existing Arctic observing systems and contribute with innovative solutions to fill some of the critical gaps in the selected networks. INTAROS will develop a platform, iAOS, to search for and access data from distributed databases. The evolution into a sustainable Arctic observing system requires coordination, mobilization and cooperation between the existing European and international infrastructures (in-situ and remote, including space-based), the modeling communities and relevant stakeholder groups. INTAROS will include development of community-based observing systems, where local knowledge is merged with scientific data. Multidisciplinary data integrated under INTAROS will contribute to better understanding of interactions and coupling in the complex Arctic ice-ocean-land-atmosphere system. An integrated Arctic Observation System will enable better-informed decisions and better-documented processes within key sectors (e.g. local communities, shipping, tourism

  8. Ice-tethered measurement platforms in the Arctic Ocean: a contribution by the FRAM infrastructure program (United States)

    Hoppmann, Mario; Nicolaus, Marcel; Rabe, Benjamin; Wenzhöfer, Frank; Katlein, Christian; Scholz, Daniel


    The Arctic Ocean has been in the focus of many studies during recent years, investigating the state, the causes and the implications of the observed rapid transition towards a thinner and younger sea-ice cover. However, consistent observational datasets of sea ice, ocean and atmosphere are still sparse due to the limited accessibility and harsh environmental conditions. One important tool to fill this gap has become more and more feasible during recent years: autonomous, ice-tethered measurement platforms (buoys). These drifting instruments independently transmit their data via satellites, and enable observations over larger areas and over longer time periods than manned expeditions, even throughout the winter. One aim of the newly established FRAM (FRontiers in Arctic marine Monitoring) infrastructure program at the Alfred-Wegener-Institute is to realize and maintain an interdisciplinary network of buoys in the Arctic Ocean, contributing to an integrated, Arctic-wide observatory. The additional buoy infrastructure, ship-time, and developments provided by FRAM are critical elements in the ongoing international effort to fill the large data gaps in a rapidly changing Arctic Ocean. Our focus is the particularly underrepresented Eurasian Basin. Types of instruments range from snow depth beacons and ice mass balance buoys for monitoring ice growth and snow accumulation, over radiation and weather stations for energy budget estimates, to ice-tethered profiling systems for upper ocean monitoring. Further, development of new bio-optical and biogeochemical buoys is expected to enhance our understanding of bio-physical processes associated with Arctic sea ice. The first set of FRAM buoys was deployed in September 2015 from RV Polarstern. All datasets are publicly available on dedicated web portals. Near real time data are reported into international initiatives, such as the Global Telecommunication System (GTS) and the International Arctic Buoy Programme (IABP). The

  9. Arctic climate tipping points. (United States)

    Lenton, Timothy M


    There is widespread concern that anthropogenic global warming will trigger Arctic climate tipping points. The Arctic has a long history of natural, abrupt climate changes, which together with current observations and model projections, can help us to identify which parts of the Arctic climate system might pass future tipping points. Here the climate tipping points are defined, noting that not all of them involve bifurcations leading to irreversible change. Past abrupt climate changes in the Arctic are briefly reviewed. Then, the current behaviour of a range of Arctic systems is summarised. Looking ahead, a range of potential tipping phenomena are described. This leads to a revised and expanded list of potential Arctic climate tipping elements, whose likelihood is assessed, in terms of how much warming will be required to tip them. Finally, the available responses are considered, especially the prospects for avoiding Arctic climate tipping points.

  10. Comparison of Passive Microwave-Derived Early Melt Onset Records on Arctic Sea Ice (United States)

    Bliss, Angela C.; Miller, Jeffrey A.; Meier, Walter N.


    Two long records of melt onset (MO) on Arctic sea ice from passive microwave brightness temperatures (Tbs) obtained by a series of satellite-borne instruments are compared. The Passive Microwave (PMW) method and Advanced Horizontal Range Algorithm (AHRA) detect the increase in emissivity that occurs when liquid water develops around snow grains at the onset of early melting on sea ice. The timing of MO on Arctic sea ice influences the amount of solar radiation absorbed by the ice-ocean system throughout the melt season by reducing surface albedos in the early spring. This work presents a thorough comparison of these two methods for the time series of MO dates from 1979through 2012. The methods are first compared using the published data as a baseline comparison of the publically available data products. A second comparison is performed on adjusted MO dates we produced to remove known differences in inter-sensor calibration of Tbs and masking techniques used to develop the original MO date products. These adjustments result in a more consistent set of input Tbs for the algorithms. Tests of significance indicate that the trends in the time series of annual mean MO dates for the PMW and AHRA are statistically different for the majority of the Arctic Ocean including the Laptev, E. Siberian, Chukchi, Beaufort, and central Arctic regions with mean differences as large as 38.3 days in the Barents Sea. Trend agreement improves for our more consistent MO dates for nearly all regions. Mean differences remain large, primarily due to differing sensitivity of in-algorithm thresholds and larger uncertainties in thin-ice regions.

  11. Arctic Ocean freshwater composition, pathways and transformations from a passive tracer simulation

    Directory of Open Access Journals (Sweden)

    Per Pemberton


    Full Text Available Freshwater (FW induced transformations in the upper Arctic Ocean were studied using a coupled regional sea ice-ocean model driven by winds and thermodynamic forcing from a reanalysis of data during the period 1948–2011, focusing on the mean state during 1968–2011. Using passive tracers to mark a number of FW sources and sinks, their mean composition, pathways and export were examined. The distribution of the simulated FW height reproduced the known features of the Arctic Ocean and volume-integrated FW content matched climatological estimates reasonably well. Input from Eurasian rivers and extraction by sea-ice formation dominate the composition of the Arctic FW content whilst Pacific water increases in importance in the Canadian Basin. Though pathways generally agreed with previous studies the locus of the Eurasian runoff shelf-basin transport centred at the Alpha-Mendeleyev ridge, shifting the Pacific–Atlantic front eastwards. A strong coupling between tracers representing Eurasian runoff and sea-ice formation showed how water modified on the shelf spreads across the Arctic and mainly exits through the Fram Strait. Transformation to salinity dependent coordinates showed how Atlantic water is modified by both low-salinity shelf and Pacific waters in an estuary-like overturning producing water masses of intermediate salinity that are exported to the Nordic Seas. A total halocline renewal rate of 1.0 Sv, including both shelf-basin exchange and cross-isohaline flux, was estimated from the transports: both components were of equal magnitude. The model's halocline shelf-basin exchange is dominated by runoff and sea-ice processes at the western shelves (the Barents and Kara seas and Pacific water at the eastern shelves (the Laptev, East Siberian and Chukchi seas.

  12. Effects of an Arctic under-ice bloom on solar radiant heating of the water column (United States)

    Taskjelle, Torbjørn; Granskog, Mats A.; Pavlov, Alexey K.; Hudson, Stephen R.; Hamre, Børge


    The deposition of solar energy in the upper Arctic Ocean depends, among other things, on the composition of the water column. During the N-ICE2015 expedition, a drift in the Arctic pack ice north of Svalbard, an under-ice phytoplankton bloom was encountered in May 2015. This bloom led to significant changes in the inherent optical properties (IOPs) of the upper ocean. Mean values of total water absorption in the upper 20 m of the water column were up to 4 times higher during the bloom than prior to it. The total water attenuation coefficient increased by a factor of up to around 7. Radiative transfer modeling, with measured IOPs as input, has been performed with a coupled atmosphere-ice-ocean model. Simulations are used to investigate the change in depth-dependent solar heating of the ocean after the onset of the bloom, for wavelengths in the region 350-700 nm. Effects of clouds, sea ice cover, solar zenith angle, as well as the average cosine for scattering of the ocean inclusions are evaluated. An increase in energy absorption in the upper 10 m of about 36% is found under 25 cm ice with 2 cm snow, for bloom conditions relative to prebloom conditions, which may have implications for ice melt and growth in spring. Thicker clouds and lower sun reduce the irradiance available, but lead to an increase in relative absorption.

  13. Approaching a Postcolonial Arctic

    DEFF Research Database (Denmark)

    Jensen, Lars


    This article explores different postcolonially configured approaches to the Arctic. It begins by considering the Arctic as a region, an entity, and how the customary political science informed approaches are delimited by their focus on understanding the Arctic as a region at the service of the co......-colonial presences in the Arctic before moving on to consider artworks about the Arctic that arguably through their transgressive forms pushes at the boundaries of geopolitical, geohistorical and geoaesthetic approaches.......This article explores different postcolonially configured approaches to the Arctic. It begins by considering the Arctic as a region, an entity, and how the customary political science informed approaches are delimited by their focus on understanding the Arctic as a region at the service...... of the contemporary neoliberal order. It moves on to explore how different parts of the Arctic are inscribed in a number of sub-Arctic nation-state binds, focusing mainly on Canada and Denmark. The article argues that the postcolonial can be understood as a prism or a methodology that asks pivotal questions to all...

  14. MIZEX. A Program for Mesoscale Air-Ice-Ocean Interaction Experiments in Arctic Marginal Ice Zones. II. A Science Plan for a Summer Marginal Ice Zone Experiment in the Fram Strait/Greenland Sea: 1984. (United States)


    ways. Precipitation over the ocean decreases the salinity of the mixed layer and affects thermohaline convection, and over ice may cause melting or...will slow down the sampling rate. Real time analysis is required to lo- cate and track eddies as well as to discover upwell- ing events when they

  15. MIZEX (Marginal Ice Zone Program): A Program for Mesoscale Air-Ice-Ocean Interaction Experimemts om Arctic Marginal Ice Zones. V. MIZEX 84. Summer Experiment PI (Principal Investigator) Preliminary Reports, (United States)


    objects in view of part project ol/(fetch laws ) as well as the influence 3a of the MIZEX 󈨘 exreriment concer- of the eventually existing ice bands...other extreme, virtually random ,hri;sental alinments were also noted. These orientation differences rrohaily reflect c- hanse : in current were briefly reviewed at the local terminal, edited as necessary, and transmitted via electronic mail to members of ’snmmrnizex.ltst’. The average

  16. Chemical Clues of a Changing Upper Arctic Ocean Circulation: A tribute to John M. Edmond (United States)

    Falkner, K. K.


    Chemical Clues of a Changing Upper Arctic Ocean Circulation: A tribute to John M. Edmond In April 2000, an international research team, supported by the National Science Foundation (NSF), embarked on a five-year program to undertake atmosphere-ice-ocean observations at distributed locations in the high Arctic Ocean. The first temporary camp at the North Pole that year laid the groundwork for taking the pulse of the Arctic Ocean and learning how the world's northernmost sea helps regulate global climate. The Arctic Ocean has been affected in recent years by dramatic thinning of sea ice and shifts in ocean circulation which seem to be related to a pattern of change in the atmospheric circulation of the Northern Hemisphere. The objective of the "North Pole Environmental Observatory" or NPEO is to document further change and to understand what is controlling the Arctic system. Among other things, the NPEO includes a hydrographic component in which Twin Otter aircraft are landed on the ice at targeted stations in order to record ocean properties and take water samples through holes drilled in the ice. I am responsible for contributing chemical measurements to deciphering upper ocean circulation patterns under the ice. Properties analyzed thus far include salinity, nutrients, oxygen, oxygen isotopic composition of water and barium. Results are posted at this web-site by year. This site is linked to the main project web-site where additional information about NPEO can be found. In my AGU presentation, I will describe the challenging field program and summarize implications of the chemical data to date. The news of John Edmond's untimely death reached me while I was en route to the North Pole camp this past April. Seemingly endless hours on a Canadian Hercules allowed me to reflect on the many influences John had on me as his graduate student and beyond. One thing is certain; there was no way in hell I'd have been

  17. Research with Arctic peoples

    DEFF Research Database (Denmark)

    Smith, H Sally; Bjerregaard, Peter; Chan, Hing Man


    Arctic peoples are spread over eight countries and comprise 3.74 million residents, of whom 9% are indigenous. The Arctic countries include Canada, Finland, Greenland (Denmark), Iceland, Norway, Russia, Sweden and the United States. Although Arctic peoples are very diverse, there are a variety...... entitled "Research with Arctic Peoples: Unique Research Opportunities in Heart, Lung, Blood and Sleep Disorders". The meeting was international in scope with investigators from Greenland, Iceland and Russia, as well as Canada and the United States. Multiple health agencies from Canada and the United States...

  18. Arctic wind energy

    Energy Technology Data Exchange (ETDEWEB)

    Peltola, E. [Kemijoki Oy (Finland); Holttinen, H.; Marjaniemi, M. [VTT Energy, Espoo (Finland); Tammelin, B. [Finnish Meteorological Institute, Helsinki (Finland)


    Arctic wind energy research was aimed at adapting existing wind technologies to suit the arctic climatic conditions in Lapland. Project research work included meteorological measurements, instrument development, development of a blade heating system for wind turbines, load measurements and modelling of ice induced loads on wind turbines, together with the development of operation and maintenance practices in arctic conditions. As a result the basis now exists for technically feasible and economically viable wind energy production in Lapland. New and marketable products, such as blade heating systems for wind turbines and meteorological sensors for arctic conditions, with substantial export potential, have also been developed. (orig.)

  19. Prognostic Performance Metrics (United States)

    National Aeronautics and Space Administration — This chapter presents several performance metrics for offline evaluation of prognostics algorithms. A brief overview of different methods employed for performance...

  20. Prognostics for Microgrid Components (United States)

    Saxena, Abhinav


    Prognostics is the science of predicting future performance and potential failures based on targeted condition monitoring. Moving away from the traditional reliability centric view, prognostics aims at detecting and quantifying the time to impending failures. This advance warning provides the opportunity to take actions that can preserve uptime, reduce cost of damage, or extend the life of the component. The talk will focus on the concepts and basics of prognostics from the viewpoint of condition-based systems health management. Differences with other techniques used in systems health management and philosophies of prognostics used in other domains will be shown. Examples relevant to micro grid systems and subsystems will be used to illustrate various types of prediction scenarios and the resources it take to set up a desired prognostic system. Specifically, the implementation results for power storage and power semiconductor components will demonstrate specific solution approaches of prognostics. The role of constituent elements of prognostics, such as model, prediction algorithms, failure threshold, run-to-failure data, requirements and specifications, and post-prognostic reasoning will be explained. A discussion on performance evaluation and performance metrics will conclude the technical discussion followed by general comments on open research problems and challenges in prognostics.

  1. White Arctic vs. Blue Arctic: Making Choices (United States)

    Pfirman, S. L.; Newton, R.; Schlosser, P.; Pomerance, R.; Tremblay, B.; Murray, M. S.; Gerrard, M.


    As the Arctic warms and shifts from icy white to watery blue and resource-rich, tension is arising between the desire to restore and sustain an ice-covered Arctic and stakeholder communities that hope to benefit from an open Arctic Ocean. If emissions of greenhouse gases to the atmosphere continue on their present trend, most of the summer sea ice cover is projected to be gone by mid-century, i.e., by the time that few if any interventions could be in place to restore it. There are many local as well as global reasons for ice restoration, including for example, preserving the Arctic's reflectivity, sustaining critical habitat, and maintaining cultural traditions. However, due to challenges in implementing interventions, it may take decades before summer sea ice would begin to return. This means that future generations would be faced with bringing sea ice back into regions where they have not experienced it before. While there is likely to be interest in taking action to restore ice for the local, regional, and global services it provides, there is also interest in the economic advancement that open access brings. Dealing with these emerging issues and new combinations of stakeholders needs new approaches - yet environmental change in the Arctic is proceeding quickly and will force the issues sooner rather than later. In this contribution we examine challenges, opportunities, and responsibilities related to exploring options for restoring Arctic sea ice and potential pathways for their implementation. Negotiating responses involves international strategic considerations including security and governance, meaning that along with local communities, state decision-makers, and commercial interests, national governments will have to play central roles. While these issues are currently playing out in the Arctic, similar tensions are also emerging in other regions.

  2. Arctic circulation regimes. (United States)

    Proshutinsky, Andrey; Dukhovskoy, Dmitry; Timmermans, Mary-Louise; Krishfield, Richard; Bamber, Jonathan L


    Between 1948 and 1996, mean annual environmental parameters in the Arctic experienced a well-pronounced decadal variability with two basic circulation patterns: cyclonic and anticyclonic alternating at 5 to 7 year intervals. During cyclonic regimes, low sea-level atmospheric pressure (SLP) dominated over the Arctic Ocean driving sea ice and the upper ocean counterclockwise; the Arctic atmosphere was relatively warm and humid, and freshwater flux from the Arctic Ocean towards the subarctic seas was intensified. By contrast, during anticylonic circulation regimes, high SLP dominated driving sea ice and the upper ocean clockwise. Meanwhile, the atmosphere was cold and dry and the freshwater flux from the Arctic to the subarctic seas was reduced. Since 1997, however, the Arctic system has been under the influence of an anticyclonic circulation regime (17 years) with a set of environmental parameters that are atypical for this regime. We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from the Arctic Ocean and Greenland impact environmental conditions and interrupt their decadal variability. © 2015 The Authors.

  3. GPU Accelerated Prognostics (United States)

    Gorospe, George E., Jr.; Daigle, Matthew J.; Sankararaman, Shankar; Kulkarni, Chetan S.; Ng, Eley


    Prognostic methods enable operators and maintainers to predict the future performance for critical systems. However, these methods can be computationally expensive and may need to be performed each time new information about the system becomes available. In light of these computational requirements, we have investigated the application of graphics processing units (GPUs) as a computational platform for real-time prognostics. Recent advances in GPU technology have reduced cost and increased the computational capability of these highly parallel processing units, making them more attractive for the deployment of prognostic software. We present a survey of model-based prognostic algorithms with considerations for leveraging the parallel architecture of the GPU and a case study of GPU-accelerated battery prognostics with computational performance results.

  4. Arctic Climate Systems Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ivey, Mark D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Robinson, David G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Boslough, Mark B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Backus, George A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Peterson, Kara J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); van Bloemen Waanders, Bart G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Swiler, Laura Painton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Desilets, Darin Maurice [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Reinert, Rhonda Karen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    This study began with a challenge from program area managers at Sandia National Laboratories to technical staff in the energy, climate, and infrastructure security areas: apply a systems-level perspective to existing science and technology program areas in order to determine technology gaps, identify new technical capabilities at Sandia that could be applied to these areas, and identify opportunities for innovation. The Arctic was selected as one of these areas for systems level analyses, and this report documents the results. In this study, an emphasis was placed on the arctic atmosphere since Sandia has been active in atmospheric research in the Arctic since 1997. This study begins with a discussion of the challenges and benefits of analyzing the Arctic as a system. It goes on to discuss current and future needs of the defense, scientific, energy, and intelligence communities for more comprehensive data products related to the Arctic; assess the current state of atmospheric measurement resources available for the Arctic; and explain how the capabilities at Sandia National Laboratories can be used to address the identified technological, data, and modeling needs of the defense, scientific, energy, and intelligence communities for Arctic support.

  5. Scaling properties of Arctic sea ice deformation in high-resolution viscous-plastic sea ice models and satellite observations (United States)

    Hutter, Nils; Losch, Martin; Menemenlis, Dimitris


    Sea ice models with the traditional viscous-plastic (VP) rheology and very high grid resolution can resolve leads and deformation rates that are localised along Linear Kinematic Features (LKF). In a 1-km pan-Arctic sea ice-ocean simulation, the small scale sea-ice deformations in the Central Arctic are evaluated with a scaling analysis in relation to satellite observations of the Envisat Geophysical Processor System (EGPS). A new coupled scaling analysis for data on Eulerian grids determines the spatial and the temporal scaling as well as the coupling between temporal and spatial scales. The spatial scaling of the modelled sea ice deformation implies multi-fractality. The spatial scaling is also coupled to temporal scales and varies realistically by region and season. The agreement of the spatial scaling and its coupling to temporal scales with satellite observations and models with the modern elasto-brittle rheology challenges previous results with VP models at coarse resolution where no such scaling was found. The temporal scaling analysis, however, shows that the VP model does not fully resolve the intermittency of sea ice deformation that is observed in satellite data.

  6. Collaborative Project. Understanding the effects of tides and eddies on the ocean dynamics, sea ice cover and decadal/centennial climate prediction using the Regional Arctic Climate Model (RACM)

    Energy Technology Data Exchange (ETDEWEB)

    Hutchings, Jennifer [Univ. of Alaska, Fairbanks, AK (United States); Joseph, Renu [Univ. of Alaska, Fairbanks, AK (United States)


    The goal of this project is to develop an eddy resolving ocean model (POP) with tides coupled to a sea ice model (CICE) within the Regional Arctic System Model (RASM) to investigate the importance of ocean tides and mesoscale eddies in arctic climate simulations and quantify biases associated with these processes and how their relative contribution may improve decadal to centennial arctic climate predictions. Ocean, sea ice and coupled arctic climate response to these small scale processes will be evaluated with regard to their influence on mass, momentum and property exchange between oceans, shelf-basin, ice-ocean, and ocean-atmosphere. The project will facilitate the future routine inclusion of polar tides and eddies in Earth System Models when computing power allows. As such, the proposed research addresses the science in support of the BER’s Climate and Environmental Sciences Division Long Term Measure as it will improve the ocean and sea ice model components as well as the fully coupled RASM and Community Earth System Model (CESM) and it will make them more accurate and computationally efficient.

  7. Prognostics of Power MOSFET (United States)

    National Aeronautics and Space Administration — This paper demonstrates how to apply prognostics to power MOSFETs (metal oxide field effect transistor). The methodology uses thermal cycling to age devices and...

  8. Historical Arctic Rawinsonde Archive (United States)

    National Aeronautics and Space Administration — Note: This data set is now on FTP so references to CD-ROM are historic and no longer applicable. The Historical Arctic Rawinsonde Archive is on FTP, and it contains...

  9. Arctic_Bathymetry (United States)

    U.S. Geological Survey, Department of the Interior — Models project the Arctic Ocean will become undersaturated with respect to carbonate minerals in the next decade. Recent field results indicate parts may already be...

  10. Encyclopedia of the Arctic

    National Research Council Canada - National Science Library

    Nuttall, M


    ..., physical processes, life sciences, and environmental change. This work is the result of over 375 international scholars and writers in all fields and relate to the eight Arctic countries: Canada, USA (Alaska), Greenland (Denmark...

  11. Live from the Arctic (United States)

    Warnick, W. K.; Haines-Stiles, G.; Warburton, J.; Sunwood, K.


    For reasons of geography and geophysics, the poles of our planet, the Arctic and Antarctica, are places where climate change appears first: they are global canaries in the mine shaft. But while Antarctica (its penguins and ozone hole, for example) has been relatively well-documented in recent books, TV programs and journalism, the far North has received somewhat less attention. This project builds on and advances what has been done to date to share the people, places, and stories of the North with all Americans through multiple media, over several years. In a collaborative project between the Arctic Research Consortium of the United States (ARCUS) and PASSPORT TO KNOWLEDGE, Live from the Arctic will bring the Arctic environment to the public through a series of primetime broadcasts, live and taped programming, interactive virtual field trips, and webcasts. The five-year project will culminate during the 2007-2008 International Polar Year (IPY). Live from the Arctic will: A. Promote global understanding about the value and world -wide significance of the Arctic, B. Bring cutting-edge research to both non-formal and formal education communities, C. Provide opportunities for collaboration between arctic scientists, arctic communities, and the general public. Content will focus on the following four themes. 1. Pan-Arctic Changes and Impacts on Land (i.e. snow cover; permafrost; glaciers; hydrology; species composition, distribution, and abundance; subsistence harvesting) 2. Pan-Arctic Changes and Impacts in the Sea (i.e. salinity, temperature, currents, nutrients, sea ice, marine ecosystems (including people, marine mammals and fisheries) 3. Pan-Arctic Changes and Impacts in the Atmosphere (i.e. precipitation and evaporation; effects on humans and their communities) 4. Global Perspectives (i.e. effects on humans and communities, impacts to rest of the world) In The Earth is Faster Now, a recent collection of comments by members of indigenous arctic peoples, arctic

  12. Arctic Geology (geoarcst) (United States)

    U.S. Geological Survey, Department of the Interior — The digitally compiled map includes geology, oil and gas field centerpoints, and geologic provinces of the Arctic (North Pole area encircled by 640 N Latitude). The...

  13. Arctic Bathymetry (batharcst) (United States)

    U.S. Geological Survey, Department of the Interior — The digitally compiled map includes geology, oil and gas field centerpoints, and geologic provinces of the Arctic (North Pole area encircled by 640 N Latitude). The...

  14. Palliative medicine review: prognostication. (United States)

    Glare, Paul A; Sinclair, Christian T


    Prognostication, along with diagnosis and treatment, is a traditional core clinical skill of the physician. Many patients and families receiving palliative care want information about life expectancy to help plan realistically for their futures. Although underappreciated, prognosis is, or at least should be, part of every clinical decision. Despite this crucial role, expertise in the art and science of prognostication diminished during the twentieth century, due largely to the ascendancy of accurate diagnostic tests and effective therapies. Consequently, "Doctor, how long do I have?" is a question most physicians find unprepared to answer effectively. As we focus on palliative care in the twenty-first century, prognostication will need to be restored as a core clinical proficiency. The discipline of palliative medicine can provide leadership in this direction. This paper begins by discussing a framework for understanding prognosis and how its different domains might be applied to all patients with life limiting illness, although the main focus of the paper is predicting survival in patients with cancer. Examples of prognostic tools are provided, although the subjective assessment of prognosis remains important in the terminally ill. Other issues addressed include: the importance of prognostication in terms of clinical decision-making, discharge planning, and care planning; the impact of prognosis on hospice referrals and patient/family satisfaction; and physicians' willingness to prognosticate.

  15. USGS Arctic Science Strategy (United States)

    Shasby, Mark; Smith, Durelle


    The United States is one of eight Arctic nations responsible for the stewardship of a polar region undergoing dramatic environmental, social, and economic changes. Although warming and cooling cycles have occurred over millennia in the Arctic region, the current warming trend is unlike anything recorded previously and is affecting the region faster than any other place on Earth, bringing dramatic reductions in sea ice extent, altered weather, and thawing permafrost. Implications of these changes include rapid coastal erosion threatening villages and critical infrastructure, potentially significant effects on subsistence activities and cultural resources, changes to wildlife habitat, increased greenhouse-gas emissions from thawing permafrost, threat of invasive species, and opening of the Arctic Ocean to oil and gas exploration and increased shipping. The Arctic science portfolio of the U.S. Geological Survey (USGS) and its response to climate-related changes focuses on landscapescale ecosystem and natural resource issues and provides scientific underpinning for understanding the physical processes that shape the Arctic. The science conducted by the USGS informs the Nation's resource management policies and improves the stewardship of the Arctic Region.

  16. Turbulent heat and momentum fluxes in the upper ocean under Arctic sea ice (United States)

    Peterson, Algot K.; Fer, Ilker; McPhee, Miles G.; Randelhoff, Achim


    We report observations of heat and momentum fluxes measured in the ice-ocean boundary layer from four drift stations between January and June 2015, covering from the typical Arctic basin conditions in the Nansen Basin to energetic spots of interaction with the warm Atlantic Water branches near the Yermak Plateau and over the North Spitsbergen slope. A wide range of oceanic turbulent heat flux values are observed, reflecting the variations in space and time over the five month duration of the experiment. Oceanic heat flux is weakly positive in winter over the Nansen Basin during quiescent conditions, increasing by an order of magnitude during storm events. An event of local upwelling and mixing in the winter-time Nansen basin highlights the importance of individual events. Spring-time drift is confined to the Yermak Plateau and its slopes, where vertical mixing is enhanced. Wind events cause an approximate doubling of oceanic heat fluxes compared to calm periods. In June, melting conditions near the ice edge lead to heat fluxes of O(100 W m-2). The combination of wind forcing with shallow Atlantic Water layer and proximity to open waters leads to maximum heat fluxes reaching 367 W m-2, concurrent with rapid melting. Observed ocean-to-ice heat fluxes agree well with those estimated from a bulk parameterization except when accumulated freshwater from sea ice melt in spring probably causes the bulk formula to overestimate the oceanic heat flux.

  17. Modelling the long-term evolution of worst-case Arctic oil spills. (United States)

    Blanken, Hauke; Tremblay, Louis Bruno; Gaskin, Susan; Slavin, Alexander


    We present worst-case assessments of contamination in sea ice and surface waters resulting from hypothetical well blowout oil spills at ten sites in the Arctic Ocean basin. Spill extents are estimated by considering Eulerian passive tracers in the surface ocean of the MITgcm (a hydrostatic, coupled ice-ocean model). Oil in sea ice, and contamination resulting from melting of oiled ice, is tracked using an offline Lagrangian scheme. Spills are initialized on November 1st 1980-2010 and tracked for one year. An average spill was transported 1100km and potentially affected 1.1 million km2. The direction and magnitude of simulated oil trajectories are consistent with known large-scale current and sea ice circulation patterns, and trajectories frequently cross international boundaries. The simulated trajectories of oil in sea ice match observed ice drift trajectories well. During the winter oil transport by drifting sea ice is more significant than transport with surface currents. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Arctic Rabies – A Review

    Directory of Open Access Journals (Sweden)

    Prestrud Pål


    Full Text Available Rabies seems to persist throughout most arctic regions, and the northern parts of Norway, Sweden and Finland, is the only part of the Arctic where rabies has not been diagnosed in recent time. The arctic fox is the main host, and the same arctic virus variant seems to infect the arctic fox throughout the range of this species. The epidemiology of rabies seems to have certain common characteristics in arctic regions, but main questions such as the maintenance and spread of the disease remains largely unknown. The virus has spread and initiated new epidemics also in other species such as the red fox and the racoon dog. Large land areas and cold climate complicate the control of the disease, but experimental oral vaccination of arctic foxes has been successful. This article summarises the current knowledge and the typical characteristics of arctic rabies including its distribution and epidemiology.

  19. Satellite Observations of Arctic Change (United States)

    National Aeronautics and Space Administration — The purpose of this site is to expose NASA satellite data and research on Arctic change in the form of maps that illustrate the changes taking place in the Arctic...

  20. Arctic dimension of global warming


    G. V. Alekseev


    A brief assessment of the global warming in the Arctic climate system with the emphasis on sea ice is presented. The Arctic region is coupled to the global climate system by the atmosphere and ocean circulation that providesa major contribution to the Arctic energy budget. On this basis using of special indices it is shown that amplification of warming in the Arctic is associated with the increasing of meridional heat transport from the low latitudes.

  1. Arctic security and Norway

    Energy Technology Data Exchange (ETDEWEB)

    Tamnes, Rolf


    Global warming is one of the most serious threats facing mankind. Many regions and countries will be affected, and there will be many losers. The earliest and most intense climatic changes are being experienced in the Arctic region. Arctic average temperature has risen at twice the rate of the global average in the past half century. These changes provide an early indication for the world of the environmental and societal significance of global warming. For that reason, the Arctic presents itself as an important scientific laboratory for improving our understanding of the causes and patterns of climate changes. The rapidly rising temperature threatens the Arctic ecosystem, but the human consequences seem to be far less dramatic there than in many other places in the world. According to the U.S. National Intelligence Council, Russia has the potential to gain the most from increasingly temperate weather, because its petroleum reserves become more accessible and because the opening of an Arctic waterway could provide economic and commercial advantages. Norway might also be fortunate. Some years ago, the Financial Times asked: #Left Double Quotation Mark#What should Norway do about the fact that global warming will make their climate more hospitable and enhance their financial situation, even as it inflicts damage on other parts of the world?#Right Double Quotation Mark#(Author)

  2. Sea ice thermohaline dynamics and biogeochemistry in the Arctic Ocean: Empirical and model results (United States)

    Duarte, Pedro; Meyer, Amelie; Olsen, Lasse M.; Kauko, Hanna M.; Assmy, Philipp; Rösel, Anja; Itkin, Polona; Hudson, Stephen R.; Granskog, Mats A.; Gerland, Sebastian; Sundfjord, Arild; Steen, Harald; Hop, Haakon; Cohen, Lana; Peterson, Algot K.; Jeffery, Nicole; Elliott, Scott M.; Hunke, Elizabeth C.; Turner, Adrian K.


    Large changes in the sea ice regime of the Arctic Ocean have occurred over the last decades justifying the development of models to forecast sea ice physics and biogeochemistry. The main goal of this study is to evaluate the performance of the Los Alamos Sea Ice Model (CICE) to simulate physical and biogeochemical properties at time scales of a few weeks and to use the model to analyze ice algal bloom dynamics in different types of ice. Ocean and atmospheric forcing data and observations of the evolution of the sea ice properties collected from 18 April to 4 June 2015, during the Norwegian young sea ICE expedition, were used to test the CICE model. Our results show the following: (i) model performance is reasonable for sea ice thickness and bulk salinity; good for vertically resolved temperature, vertically averaged Chl a concentrations, and standing stocks; and poor for vertically resolved Chl a concentrations. (ii) Improving current knowledge about nutrient exchanges, ice algal recruitment, and motion is critical to improve sea ice biogeochemical modeling. (iii) Ice algae may bloom despite some degree of basal melting. (iv) Ice algal motility driven by gradients in limiting factors is a plausible mechanism to explain their vertical distribution. (v) Different ice algal bloom and net primary production (NPP) patterns were identified in the ice types studied, suggesting that ice algal maximal growth rates will increase, while sea ice vertically integrated NPP and biomass will decrease as a result of the predictable increase in the area covered by refrozen leads in the Arctic Ocean.

  3. Winter transport of subsurface warm water toward the Arctic Chukchi Borderland (United States)

    Watanabe, Eiji; Onodera, Jonaotaro; Itoh, Motoyo; Nishino, Shigeto; Kikuchi, Takashi


    Winter subsurface transport of the Pacific-origin warm water toward the Arctic Chukchi Borderland located west of the Canada Basin was investigated by mooring measurements and modeling analyses. In mid-winter or spring of 2011-2014, subsurface warming signals under sea ice were detected by the multi-year bottom-tethered mooring data in the Chukchi Abyssal Plain (CAP) of the western Chukchi Borderland. Lateral advection of shelf-origin ocean heat is a key process for the subsurface warming. To address the detailed pathways and processes of subsurface warm water transport, which have not been deeply explored, an interannual experiment for 2001-2014 was performed using a pan-Arctic sea ice-ocean model configured in a high-resolution framework. The horizontal grid size was set to approximately 5 km so that narrow intense currents along complex sharp topography could be resolved. The model result captured the similar seasonality of subsurface temperature in the CAP region and produced interannual variability in the ocean heat content associated with the shelf-origin water distribution around the Chukchi Borderland. In addition to the Barrow Canyon throughflow, westward jets along the steep flank of the Chukchi shelf break constituted a primary pathway for the subsurface warm water transport toward the Chukchi Borderland in the model experiment. Since the simulated shelf break jet was much faster than main streams of the Beaufort Gyre, its role in ocean heat transport should be considered separately. Whereas ocean heat in the Chukchi shelf break region was partly lost via wind-driven turbulent mixing into upper halocline depths of approximately 20 m, a substantial amount of the subsurface warm water remained even after mid-winter. The highly stratified condition due to anomalous sea ice meltwater assisted the winter heat transport.

  4. Transmission and absorption of solar radiation by Arctic sea ice during the melt season (United States)

    Light, Bonnie; Grenfell, Thomas C.; Perovich, Donald K.


    The partitioning of incident solar radiation between sea ice, ocean, and atmosphere strongly affects the Arctic energy balance during summer. In addition to spectral albedo of the ice surface, transmission of solar radiation through the ice is critical for assessing heat and mass balances of sea ice. Observations of spectral irradiance profiles within and transmittance through ice in the Beaufort Sea during the summer of 1998 during the Surface Heat Budget of the Arctic Ocean (SHEBA) are presented. Sites representative of melting multiyear and first-year ice, along with ponded ice were measured. Observed spectral irradiance extinction coefficients (Kλ) show broad minima near 500 nm and strong increases at near-infrared wavelengths. The median Kλ at 600 nm for the bare ice cases is close to 0.8 m-1 and about 0.6 m-1 for ponded ice. Values are considerably smaller than the previously accepted value of 1.5 m-1. Radiative transfer models were used to analyze the observations and obtain inherent optical properties of the ice. Derived scattering coefficients range from 500 m-1 to 1100 m-1 in the surface layer and 8 to 30 m-1 in the ice interior. While ponded ice is known to transmit a significant amount of shortwave radiation to the ocean, the irradiance transmitted through bare, melting ice is also shown to be significant. The findings of this study predict 3-10 times more solar radiation penetrating the ice cover than predicted by a current GCM (CCSM3) parameterization, depending on ice thickness, pond coverage, stage of the melt season, and specific vertical scattering coefficient profile.

  5. Prognostics of Power MOSFET (United States)

    Celaya, Jose Ramon; Saxena, Abhinav; Vashchenko, Vladislay; Saha, Sankalita; Goebel, Kai Frank


    This paper demonstrates how to apply prognostics to power MOSFETs (metal oxide field effect transistor). The methodology uses thermal cycling to age devices and Gaussian process regression to perform prognostics. The approach is validated with experiments on 100V power MOSFETs. The failure mechanism for the stress conditions is determined to be die-attachment degradation. Change in ON-state resistance is used as a precursor of failure due to its dependence on junction temperature. The experimental data is augmented with a finite element analysis simulation that is based on a two-transistor model. The simulation assists in the interpretation of the degradation phenomena and SOA (safe operation area) change.

  6. Arctic Sea Level Reconstruction

    DEFF Research Database (Denmark)

    Svendsen, Peter Limkilde

    gauge record and makes the reconstruction much less prone to drifting away over time.Unfortunately, many of the Russian-sector tide gauge records end around 1990,leaving a fairly sparse record after this. This project examines the effect of introducing a subset of the altimetric dataset as “virtual tide......Reconstruction of historical Arctic sea level is very difficult due to the limited coverage and quality of tide gauge and altimetry data in the area. This thesis addresses many of these issues, and discusses strategies to help achieve a stable and plausible reconstruction of Arctic sea level from...... 1950 to today.The primary record of historical sea level, on the order of several decades to a few centuries, is tide gauges. Tide gauge records from around the world are collected in the Permanent Service for Mean Sea Level (PSMSL) database, and includes data along the Arctic coasts. A reasonable...

  7. Implications of sea-ice biogeochemistry for oceanic production and emissions of dimethyl sulfide in the Arctic (United States)

    Hayashida, Hakase; Steiner, Nadja; Monahan, Adam; Galindo, Virginie; Lizotte, Martine; Levasseur, Maurice


    Sea ice represents an additional oceanic source of the climatically active gas dimethyl sulfide (DMS) for the Arctic atmosphere. To what extent this source contributes to the dynamics of summertime Arctic clouds is, however, not known due to scarcity of field measurements. In this study, we developed a coupled sea ice-ocean ecosystem-sulfur cycle model to investigate the potential impact of bottom-ice DMS and its precursor dimethylsulfoniopropionate (DMSP) on the oceanic production and emissions of DMS in the Arctic. The results of the 1-D model simulation were compared with field data collected during May and June of 2010 in Resolute Passage. Our results reproduced the accumulation of DMS and DMSP in the bottom ice during the development of an ice algal bloom. The release of these sulfur species took place predominantly during the earlier phase of the melt period, resulting in an increase of DMS and DMSP in the underlying water column prior to the onset of an under-ice phytoplankton bloom. Production and removal rates of processes considered in the model are analyzed to identify the processes dominating the budgets of DMS and DMSP both in the bottom ice and the underlying water column. When openings in the ice were taken into account, the simulated sea-air DMS flux during the melt period was dominated by episodic spikes of up to 8.1 µmol m-2 d-1. Further model simulations were conducted to assess the effects of the incorporation of sea-ice biogeochemistry on DMS production and emissions, as well as the sensitivity of our results to changes of uncertain model parameters of the sea-ice sulfur cycle. The results highlight the importance of taking into account both the sea-ice sulfur cycle and ecosystem in the flux estimates of oceanic DMS near the ice margins and identify key uncertainties in processes and rates that should be better constrained by new observations.

  8. Arctic Aerosols and Sources

    DEFF Research Database (Denmark)

    Nielsen, Ingeborg Elbæk


    Since the Industrial Revolution, the anthropogenic emission of greenhouse gases has been increasing, leading to a rise in the global temperature. Particularly in the Arctic, climate change is having serious impact where the average temperature has increased almost twice as much as the global during...... aerosol contribution from wood combustion will not be sufficient. Arctic aerosols were investigated during several time periods with different instruments and time resolutions. Two years of weekly measurements of black carbon and sulfate at the Villum Research Station showed elevated concentrations during...

  9. Globalising the Arctic Climate:

    DEFF Research Database (Denmark)

    Corry, Olaf


    targets of political operations and contestations—are not simple ‘issues’ or ‘problems’ given to actors to deal with. Governance-objects emerge and are constructed through science, technology and politics, and rather than slotting neatly into existing structures, they have their own structuring effects...... on world politics. The emergence of the Arctic climate as a potential target of governance provides a case in point. The Arctic climate is becoming globalised, pushing it up the political agenda but drawing it away from its local and regional context....

  10. Human-induced Arctic moistening. (United States)

    Min, Seung-Ki; Zhang, Xuebin; Zwiers, Francis


    The Arctic and northern subpolar regions are critical for climate change. Ice-albedo feedback amplifies warming in the Arctic, and fluctuations of regional fresh water inflow to the Arctic Ocean modulate the deep ocean circulation and thus exert a strong global influence. By comparing observations to simulations from 22 coupled climate models, we find influence from anthropogenic greenhouse gases and sulfate aerosols in the space-time pattern of precipitation change over high-latitude land areas north of 55 degrees N during the second half of the 20th century. The human-induced Arctic moistening is consistent with observed increases in Arctic river discharge and freshening of Arctic water masses. This result provides new evidence that human activity has contributed to Arctic hydrological change.

  11. Prognostic factors in oligodendrogliomas

    DEFF Research Database (Denmark)

    Westergaard, L; Gjerris, F; Klinken, L


    An outcome analysis was performed on 96 patients with pure cerebral oligodendrogliomas operated in the 30-year period 1962 to 1991. The most important predictive prognostic factors were youth and no neurological deficit, demonstrated as a median survival for the group younger than 20 years of 17...

  12. How well can the observed Arctic sea ice summer retreat and winter advance be represented in the NCEP Climate Forecast System version 2? (United States)

    Collow, Thomas W.; Wang, Wanqiu; Kumar, Arun; Zhang, Jinlun


    The capability of a numerical model to simulate the statistical characteristics of the summer sea ice date of retreat (DOR) and the winter date of advance (DOA) is investigated using sea ice concentration output from the Climate Forecast System Version 2 model (CFSv2). Two model configurations are tested, the operational setting (CFSv2CFSR) which uses initial data from the Climate Forecast System Reanalysis, and a modified version (CFSv2PIOMp) which ingests sea ice thickness initialization data from the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) and includes physics modifications for a more realistic representation of heat fluxes at the sea ice top and bottom. First, a method to define DOR and DOA is presented. Then, DOR and DOA are determined from the model simulations and observational sea ice concentration from the National Aeronautics and Space Administration (NASA). Means, trends, and detrended standard deviations of DOR and DOA are compared, along with DOR/DOA rates in the Arctic Ocean. It is found that the statistics are generally similar between the model and observations, although some regional biases exist. In addition, regions of new ice retreat in recent years are represented well in CFSv2PIOMp over the Arctic Ocean, in terms of both spatial extent and timing. Overall, CFSv2PIOMp shows a reduction in error throughout the Arctic. Based on results, it is concluded that the model produces a reasonable representation of the climatology and variability statistics of DOR and DOA in most regions. This assessment serves as a prerequisite for future predictability experiments.

  13. Arctic offshore engineering

    National Research Council Canada - National Science Library

    Palmer, Andrew; Croasdale, Ken


    ... so safely, economically and with minimal risk to the environment. Singapore may at first seem a surprising place to be writing such a book, but in fact we have a significant and growing interest in the Arctic, from several directions, among them shipping and petroleum production. At Keppel we are already active in more than one of those fields, and have a ...

  14. Communicating Arctic Change (Invited) (United States)

    Serreze, M.


    Nowhere on the planet are emerging signals of climate change more visible than in the Arctic. Rapid warming, a quickly shrinking summer sea ice cover, and thawing permafrost, will have impacts that extend beyond the Arctic and may reverberate around the globe. The National Snow and Ice Data Center (NSIDC) of the University of Colorado has taken a leading role in trying to effectively communicate the science and importance of Arctic change. Our popular “Sea Ice News and Analysis” web site tracks the Arctic’s shrinking ice cover and provides scientific analysis with language that is accurate yet accessible to a wide audience. Our Education Center provides accessible information on all components of the Earth’s cryosphere, the changes being seen, and how scientists conduct research. A challenge faced by NSIDC is countering the increasing level of confusion and misinformation regarding Arctic and global change, a complex problem that reflects the low level of scientific literacy by much of the public, the difficulties many scientists face in communicating their findings in accurate but understandable terms, and efforts by some groups to deliberately misrepresent and distort climate change science. This talk will outline through examples ways in which NSIDC has been successful in science communication and education, as well as lessons learned from failures.

  15. Arctic avalanche dynamics (United States)

    Prokop, Alexander; Eiken, Mari; Ganaus, Kerstin; Rubensdotter, Lena


    Since the avalanche disaster December 19th, 2015 in Longyearbyen (Svalbard) happened, where two people were killed within settlements, the dynamic of avalanches in arctic regions is of increasing interest for hazard mapping in such areas. To investigate the flow behavior of arctic avalanches we focused on avalanches that occurred in Central Svalbard. In this regions historic avalanche events can be analyzed due to their deposition behavior visible on geomorphological maps in the run-out area of the avalanches. To get an idea about possible snow mass that was involved in the avalanches we measured the snow volume balance of recent avalanches (winters 2015/16) via terrestrial laser scanning. In this way we gained reasonable data to set calibration and input parameters for dynamic avalanche modeling. Using state of the art dynamic avalanche models allowed us to back calculate how much snow was involved in the historic avalanches that we identified on the geomorphological maps and what the return period of those events are. In our presentation we first explain our methodology; we discuss arctic avalanche behavior of the avalanches measured via terrestrial laser scanning and how the dynamic avalanche models performed for those case examples. Finally we conclude how our results can improve avalanche hazard mapping for arctic regions.

  16. The Arctic Circle (United States)

    McDonald, Siobhan


    My name is Siobhan McDonald. I am a visual artist living and working in Dublin. My studio is based in The School of Science at University College Dublin where I was Artist in Residence 2013-2015. A fascination with time and the changeable nature of landmass has led to ongoing conversations with scientists and research institutions across the interweaving disciplines of botany, biology and geology. I am developing a body of work following a recent research trip to the North Pole where I studied the disappearing landscape of the Arctic. Prompted by my experience of the Arctic shelf receding, this new work addresses issues of the instability of the earth's materiality. The work is grounded in an investigation of material processes, exploring the dynamic forces that transform matter and energy. This project combines art and science in a fascinating exploration of one of the Earth's last relatively untouched wilderness areas - the High Arctic to bring audiences on journeys to both real and artistically re-imagined Arctic spaces. CRYSTALLINE'S pivotal process is collaboration: with The European Space Agency; curator Helen Carey; palaeontologist Prof. Jenny McElwain, UCD; and with composer Irene Buckley. CRYSTALLINE explores our desire to make corporeal contact with geological phenomena in Polar Regions. From January 2016, in my collaboration with Jenny McElwain, I will focus on the study of plants and atmospheres from the Arctic regions as far back as 400 million years ago, to explore the essential 'nature' that, invisible to the eye, acts as imaginary portholes into other times. This work will be informed by my arctic tracings of sounds and images recorded in the glaciers of this disappearing frozen landscape. In doing so, the urgencies around the tipping of natural balances in this fragile region will be revealed. The final work will emerge from my forthcoming residency at the ESA in spring 2016. Here I will conduct a series of workshops in ESA Madrid to work with

  17. Tsunami in the Arctic (United States)

    Kulikov, Evgueni; Medvedev, Igor; Ivaschenko, Alexey


    The severity of the climate and sparsely populated coastal regions are the reason why the Russian part of the Arctic Ocean belongs to the least studied areas of the World Ocean. In the same time intensive economic development of the Arctic region, specifically oil and gas industry, require studies of potential thread natural disasters that can cause environmental and technical damage of the coastal and maritime infrastructure of energy industry complex (FEC). Despite the fact that the seismic activity in the Arctic can be attributed to a moderate level, we cannot exclude the occurrence of destructive tsunami waves, directly threatening the FEC. According to the IAEA requirements, in the construction of nuclear power plants it is necessary to take into account the impact of all natural disasters with frequency more than 10-5 per year. Planned accommodation in the polar regions of the Russian floating nuclear power plants certainly requires an adequate risk assessment of the tsunami hazard in the areas of their location. Develop the concept of tsunami hazard assessment would be based on the numerical simulation of different scenarios in which reproduced the hypothetical seismic sources and generated tsunamis. The analysis of available geological, geophysical and seismological data for the period of instrumental observations (1918-2015) shows that the highest earthquake potential within the Arctic region is associated with the underwater Mid-Arctic zone of ocean bottom spreading (interplate boundary between Eurasia and North American plates) as well as with some areas of continental slope within the marginal seas. For the Arctic coast of Russia and the adjacent shelf area, the greatest tsunami danger of seismotectonic origin comes from the earthquakes occurring in the underwater Gakkel Ridge zone, the north-eastern part of the Mid-Arctic zone. In this area, one may expect earthquakes of magnitude Mw ˜ 6.5-7.0 at a rate of 10-2 per year and of magnitude Mw ˜ 7.5 at a

  18. Significance analysis of prognostic signatures.

    Directory of Open Access Journals (Sweden)

    Andrew H Beck

    Full Text Available A major goal in translational cancer research is to identify biological signatures driving cancer progression and metastasis. A common technique applied in genomics research is to cluster patients using gene expression data from a candidate prognostic gene set, and if the resulting clusters show statistically significant outcome stratification, to associate the gene set with prognosis, suggesting its biological and clinical importance. Recent work has questioned the validity of this approach by showing in several breast cancer data sets that "random" gene sets tend to cluster patients into prognostically variable subgroups. This work suggests that new rigorous statistical methods are needed to identify biologically informative prognostic gene sets. To address this problem, we developed Significance Analysis of Prognostic Signatures (SAPS which integrates standard prognostic tests with a new prognostic significance test based on stratifying patients into prognostic subtypes with random gene sets. SAPS ensures that a significant gene set is not only able to stratify patients into prognostically variable groups, but is also enriched for genes showing strong univariate associations with patient prognosis, and performs significantly better than random gene sets. We use SAPS to perform a large meta-analysis (the largest completed to date of prognostic pathways in breast and ovarian cancer and their molecular subtypes. Our analyses show that only a small subset of the gene sets found statistically significant using standard measures achieve significance by SAPS. We identify new prognostic signatures in breast and ovarian cancer and their corresponding molecular subtypes, and we show that prognostic signatures in ER negative breast cancer are more similar to prognostic signatures in ovarian cancer than to prognostic signatures in ER positive breast cancer. SAPS is a powerful new method for deriving robust prognostic biological signatures from clinically

  19. Arctic Terrestrial Biodiversity Monitoring Plan

    DEFF Research Database (Denmark)

    Christensen, Tom; Payne, J.; Doyle, M.

    The Conservation of Arctic Flora and Fauna (CAFF), the biodiversity working group of the Arctic Council, established the Circumpolar Biodiversity Monitoring Program (CBMP) to address the need for coordinated and standardized monitoring of Arctic environments. The CBMP includes an international ne....... Where are the areas of high ecological importance including, for example, resilient and vulnerable areas (related to the FECs) and where are drivers having the greatest impact?...

  20. Change Seen by NPEO in the Central Arctic Ocean, 2000-2006, and Implications for Coupling with the Atmosphere (United States)

    Morison, J.; Aagaard, K.; Falkner, K.; Kikuchi, T.; McPhee, M.; Moritz, D.; Overland, J.; Steele, M.


    The North Pole Environmental Observatory (NPEO) was established in 2000 as a means of tracking change in the central Arctic Basin. The NPEO is a distributed observatory consisting of three parts: an automated drifting station that samples air-ice-ocean conditions as it drifts from the Pole toward Fram Strait; a deep ocean mooring near the Pole; and repeated airborne hydrographic surveys that track changes along key sections radiating from the Pole. The North Pole region shows large changes during the past decade-and-a-half. In the 1990s hydrographic data demonstrated a strong increase in upper ocean salinity associated with a more cyclonic Arctic Ocean circulation, and a large warming of the Atlantic layer propagating in from the Norwegian Sea. The decrease in Arctic Ocean sea ice thickness up through the 1990s was also apparent at the Pole. Hydrographic measurements made by the NPEO have shown that conditions since 2000 have relaxed toward the pre-1990 state. Recent analysis suggests that this change is linked to a decline in the Arctic Oscillation (AO) index following the sharp rise in the AO in the early 1990s and a concomitant spin-up of the ocean. The moored records show both multi-year trends and rapid changes that suggest a close connection of the interior ocean that overlies the abyssal plain with the boundary current that rings the Eurasian Basin. Ice thickness measurements from the first year of the mooring, 2001-02, agree with the estimates of reduced thickness characterizing the 1990s but the thickness records from 2002-03, 2004-05, and arguably 2005-06 show a progressive thickening of the ice at the Pole. The relation of this thickening to ice age and advection patterns is being explored. The surface atmospheric state represents a mix of 1990s-like conditions and those prevailing earlier. For example, while 2003 was a year of minimum ice extent in the Beaufort Sea, the North Pole region had a particularly cold summer. NPEO is scheduled to continue

  1. Disparities in Arctic Health

    Centers for Disease Control (CDC) Podcasts


    Life at the top of the globe is drastically different. Harsh climate devoid of sunlight part of the year, pockets of extreme poverty, and lack of physical infrastructure interfere with healthcare and public health services. Learn about the challenges of people in the Arctic and how research and the International Polar Year address them.  Created: 2/4/2008 by Emerging Infectious Diseases.   Date Released: 2/20/2008.

  2. Russia in the Arctic (United States)


    that he hopes the ice will melt soon.98 But the capabilities of 27 Russian ports are not adequate to receive more ships. The port of Murmansk already...on board the Arktika nuclear icebreaker in Murmansk , Putin gave assur- ances that the volume of cargo shipments in the Arctic might reach more than...the Murmansk shipping line commissioned in 2007 can just barely be considered a new one, since its construction at the Baltic Shipyards in St

  3. Arctic Indicators of Change (United States)

    Stanitski, D.; Druckenmiller, M.; Fetterer, F. M.; Gerst, M.; Intrieri, J. M.; Kenney, M. A.; Meier, W.; Overland, J. E.; Stroeve, J. C.; Trainor, S.


    The Arctic is undergoing unprecedented change. Indicators of change enable better decision-making at the community to policy levels. The results presented here focus on a subset of physical, biological, societal, and economic indicators of Arctic change recommended in one of a group of papers emanating from the earlier National Climate Indicators System (NCIS) work led by Kenney et al. (2016). The intent of the NCIS was to establish a "system of physical, natural, and societal indicators that communicate and inform decisions about key aspects of the physical climate, climate impacts, vulnerabilities, and preparedness" in support of the sustained U.S. National Climate Assessment. Our analysis, guided by a tailored selection and recommendation criteria, resulted in a list of "existing" indicators, as well as those "in development", "recommended", and "aspirational". A goal of this effort is to identify a set of both lagging and leading indicators that is based on reliable and sustained data sources with known user communities. We intend for these indicators to guide decision-makers in their responses to climate change, and ideally help inform decisions of groups like the Arctic Council and U.S. Global Change Research Program (USGCRP) as they develop plans and priorities.

  4. Influence of Sea Ice on the Thermohaline Circulation in the Arctic-North Atlantic Ocean (United States)

    Mauritzen, Cecilie; Haekkinen, Sirpa


    A fully prognostic coupled ocean-ice model is used to study the sensitivity of the overturning cell of the Arctic-North-Atlantic system to sea ice forcing. The strength of the thermohaline cell will be shown to depend on the amount of sea ice transported from the Arctic to the Greenland Sea and further to the subpolar gyre. The model produces a 2-3 Sv increase of the meridional circulation cell at 25N (at the simulation year 15) corresponding to a decrease of 800 cu km in the sea ice export from the Arctic. Previous modeling studies suggest that interannual and decadal variability in sea ice export of this magnitude is realistic, implying that sea ice induced variability in the overturning cell can reach 5-6 Sv from peak to peak.

  5. Hot Arctic-Cold Continents: Global Impacts of Arctic Change (United States)

    Overland, James E.; Graversen, Rune Grand; Honda, Meiji


    International Polar Year Oslo Science Conference; Oslo, Norway, 8-12 June 2010; A warmer Arctic climate is influencing air pressure over the North Pole and wind patterns over the Northern Hemisphere. In response, recent data and modeling suggest that more cold and snowy winters can be expected in Europe, eastern Asia, and eastern North America. These were some of the issues discussed at the International Polar Year (IPY) conference, the largest polar science meeting ever held, with more than 2400 attendees. More than 80 scientific papers debated the state of the science regarding Arctic amplification and midlatitude connections. Arctic amplification is just that: The Arctic is warming twice as fast as the rest of the planet, caused by unique physical processes related in part to loss of sea ice. Arctic amplification is also a consequence of changes in atmospheric circulation that are anthropogenically forced, part of chaotic variability, or both.

  6. Prognostic factors in oligodendrogliomas

    DEFF Research Database (Denmark)

    Westergaard, L; Gjerris, F; Klinken, L


    .5 years and for the group older than 60 years of 13 months. The group without neurological deficits had a 5-years survival of 43 per cent while the group with deficits had a 5-years survival of 5 per cent. The 5-years survival for oligodendroglioma of grade II was 46 per cent and for grade III 10 per cent......An outcome analysis was performed on 96 patients with pure cerebral oligodendrogliomas operated in the 30-year period 1962 to 1991. The most important predictive prognostic factors were youth and no neurological deficit, demonstrated as a median survival for the group younger than 20 years of 17...

  7. Department of Defense Arctic Strategy (United States)


    shipping, and tourism —is increasing in response to the growing accessibility. Arctic and non-Arctic nations are establishing their strategies collaboration. DoD will take steps to work with other Federal departments and agencies to improve nautical charts, enhance relevant atmospheric

  8. The Arctic Circumpolar Boundary Current (United States)

    Aksenov, Yevgeny; Ivanov, Vladimir V.; Nurser, A. J. George; Bacon, Sheldon; Polyakov, Igor V.; Coward, Andrew C.; Naveira-Garabato, Alberto C.; Beszczynska-Moeller, Agnieszka


    We present high-resolution simulations and observational data as evidence of a fast current flowing along the shelf break of the Siberian and Alaskan shelves in the Arctic Ocean. Thus far, the Arctic Circumpolar Boundary Current (ACBC) has been seen as comprising two branches: the Fram Strait and Barents Sea Branches (FSB and BSB, respectively). Here we describe a new third branch, the Arctic Shelf Break Branch (ASBB). We show that the forcing mechanism for the ASBB is a combination of buoyancy loss and non-local wind, creating high pressure upstream in the Barents Sea. The potential vorticity influx through the St. Anna Trough dictates the cyclonic direction of flow of the ASBB, which is the most energetic large-scale circulation structure in the Arctic Ocean. It plays a substantial role in transporting Arctic halocline waters and exhibits a robust seasonal cycle with a summer minimum and winter maximum. The simulations show the continuity of the FSB all the way around the Arctic shelves and the uninterrupted ASBB between the St. Anna Trough and the western Fram Strait. The BSB flows continuously along the Siberian shelf as far as the Chukchi Plateau, where it partly diverges from the continental slope into the ocean interior. The Alaskan Shelf break Current (ASC) is the analog of the ASBB in the Canadian Arctic. The ASC is forced by the local winds and high upstream pressure in Bering Strait, caused by the drop in sea surface height between the Pacific and Arctic Oceans.

  9. Mining in the European Arctic

    NARCIS (Netherlands)

    van Dam, Kim; Scheepstra, Annette; Gille, Johan; Stępień, Adam; Koivurova, Timo

    The European Arctic is currently experiencing an upsurge in mining activities, but future developments will be highly sensitive to mineral price fluctuations. The EU is a major consumer and importer of Arctic raw materials. As the EU is concerned about the security of supply, it encourages domestic

  10. Seasonal Changes of Optical Sea Ice Properties in the Arctic Basin at the Russian Drifting Station NP-33 (United States)

    Gerland, S.; Makshtas, A.; Renner, A. H.


    The surface albedo of sea ice in the Arctic is crucial for the energy exchange in the atmosphere-ice-ocean system, and knowledge about spectral albedo and its seasonal change is important for corresponding studies and parameterizations in climate models. In situ spectral albedo measurements covering the entire transition from winter to summer conditions in the Arctic Basin are sparse. The Russian ice drifting station North Pole 33 (NP-33) was started in September 2004 and finished in early September 2005. In April 2005, optical sensors were installed for regular measurements of spectral surface albedo and under-ice Photosynthetically Activating Radiation (PAR), when NP-33 was located at 89° 5' N, 89° 15' W. When the station was finished in September 2005, its position was 86° 22' N, 39° 19' W. In addition to monitoring of spectral surface albedo (range 280 nm - 730 nm), and under-ice PAR radiation (average from 300 nm to 700 nm) from the freezing to the melting season, related physical parameters of the snow and ice surfaces, such as snow grain sizes and snow density were measured. The strongest changes of optical properties of snow and sea ice were observed around end of June/beginning of July, when the surface albedo in the visible range decreased from about 0.9 to 0.7, the snow thickness decreased from about 0.4 m to a few mm-thin layer or no snow cover, snow grain diameters increased from 1-3 mm to above 7 mm, and snow density increased from less than 400 kg m-3 to about 500 kg m-3. Results from these investigations will be shown, accompanied with plans for an extension of this work into the International Polar Year.

  11. NSF's ambitious Arctic system program (United States)

    Simarski, Lynn Teo

    The Arctic is the least known of any region of the world, but a new National Science Foundation program called Arctic System Science (ARCSS) aims to change that. Climate models suggest that global change will be amplified at the Earth's poles, particularly in the Arctic. Increasing carbon dioxide could change the Arctic's temperature more than 12°, as opposed to the 2-3° increase projected at the equator—a compelling reason for scientists to get to know the region better.NSF's research effort is “a systematic, multidisciplinary approach to all the science in the region,” according to Ted De Laca, head of ARCSS. The purpose of this special endeavor of the Division of Polar Programs is not to measure global change per se, he says, but to promote basic research on how the Arctic functions.

  12. AMAP Assessment 2013: Arctic Ocean acidification (United States)


    This assessment report presents the results of the 2013 AMAP Assessment of Arctic Ocean Acidification (AOA). This is the first such assessment dealing with AOA from an Arctic-wide perspective, and complements several assessments that AMAP has delivered over the past ten years concerning the effects of climate change on Arctic ecosystems and people. The Arctic Monitoring and Assessment Programme (AMAP) is a group working under the Arctic Council. The Arctic Council Ministers have requested AMAP to: - produce integrated assessment reports on the status and trends of the conditions of the Arctic ecosystems;

  13. Prognostic factors in lupus nephritis

    DEFF Research Database (Denmark)

    Faurschou, Mikkel; Starklint, Henrik; Halberg, Poul


    To evaluate the prognostic significance of clinical and renal biopsy findings in an unselected cohort of patients with systemic lupus erythematosus (SLE) and nephritis.......To evaluate the prognostic significance of clinical and renal biopsy findings in an unselected cohort of patients with systemic lupus erythematosus (SLE) and nephritis....

  14. Requirements Specifications for Prognostics: An Overview (United States)

    National Aeronautics and Space Administration — With recent advancements in prognostics methodologies there has been a significant interest in maturing Prognostics and Health Management (PHM) to increase its...

  15. On Applying the Prognostic Performance Metrics (United States)

    National Aeronautics and Space Administration — Prognostics performance evaluation has gained significant attention in the past few years. *As prognostics technology matures and more sophisticated methods for...

  16. Metrics for Offline Evaluation of Prognostic Performance (United States)

    National Aeronautics and Space Administration — Prognostic performance evaluation has gained significant attention in the past few years.*Currently, prognostics concepts lack standard definitions and suffer from...

  17. Arctic and Arctic-like rabies viruses: distribution, phylogeny and evolutionary history (United States)



    SUMMARY Forty-one newly sequenced isolates of Arctic and Arctic-like rabies viruses, were genetically compared to each other and to those available from GenBank. Four phylogenetic lineages of Arctic viruses were identified. Arctic-1 viruses circulate in Ontario, Arctic-2 viruses circulate in Siberia and Alaska, Arctic-3 viruses circulate circumpolarly, and a newly described lineage Arctic-4 circulates locally in Alaska. The oldest available isolates from Siberia (between 1950 and 1960) belong to the Arctic-2 and Arctic-3 lineages and share 98·6–99·2% N gene identity with contemporary viruses. Two lineages of Arctic-like viruses were identified in southern Asia and the Middle East (Arctic-like-1) and eastern Asia (Arctic-like-2). A time-scaled tree demonstrates that the time of the most recent common ancestor (TMRCA) of Arctic and Arctic-like viruses is dated between 1255 and 1786. Evolution of the Arctic viruses has occurred through a northerly spread. The Arctic-like-2 lineage diverged first, whereas Arctic viruses share a TMRCA with Arctic-like-1 viruses. PMID:17599781

  18. Biodiversity of arctic marine fishes

    DEFF Research Database (Denmark)

    Mecklenburg, Catherine W.; Møller, Peter Rask; Steinke, Dirk


    Taxonomic and distributional information on each fish species found in arctic marine waters is reviewed, and a list of families and species with commentary on distributional records is presented. The list incorporates results from examination of museum collections of arctic marine fishes dating...... back to the 1830s. It also incorporates results from DNA barcoding, used to complement morphological characters in evaluating problematic taxa and to assist in identification of specimens collected in recent expeditions. Barcoding results are depicted in a neighbor-joining tree of 880 CO1 (cytochrome c...... oxidase 1 gene) sequences distributed among 165 species from the arctic region and adjacent waters, and discussed in the family reviews. Using our definition of the arctic region, we count 242 species with documented presence, if 12 species that likely are synonyms are excluded. The 242 species...

  19. Russia's strategy in the Arctic

    DEFF Research Database (Denmark)

    Staun, Jørgen Meedom


    Russia's strategy in the Arctic is dominated by two overriding international relations (IR) discourses – or foreign policy directions. On the one hand, there is an IR-realism/geopolitical discourse that puts security first and often has a clear patriotic character, dealing with ‘exploring......’, ‘winning’ or ‘conquering’ the Arctic and putting power, including military power, behind Russia's national interests in the area. Opposed to this is an IR-liberalism, international law-inspired and modernisation-focused discourse, which puts cooperation first and emphasises ‘respect for international law......’, ‘negotiation’ and ‘cooperation’, and labels the Arctic as a ‘territory of dialogue’, arguing that the Arctic states all benefit the most if they cooperate peacefully. After a short but very visible media stunt in 2007 and subsequent public debate by proponents of the IR realism/geopolitical side, the IR...

  20. SCICEX: Submarine Arctic Science Program (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Submarine Arctic Science Program, SCICEX, is a federal interagency collaboration among the operational Navy, research agencies, and the marine research community...

  1. Development of arctic wind technology

    Energy Technology Data Exchange (ETDEWEB)

    Holttinen, H.; Marjaniemi, M.; Antikainen, P. [VTT Energy, Espoo (Finland)


    The climatic conditions of Lapland set special technical requirements for wind power production. The most difficult problem regarding wind power production in arctic regions is the build-up of hard and rime ice on structures of the machine

  2. Arctic NWR Land Status Maps (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a map of Arctic National Wildlife Refuge within the State of Alaska. It depicts the refuge and wilderness boundaries, hillshaded topography, and Federal,...

  3. Acquatorialities of the Arctic Region

    DEFF Research Database (Denmark)

    Harste, Gorm


    In order to describe the Arctic system I propose using a concept functionally equivalent to territoriality, namely aquatoriality. Whether communicating about territoriality or aquatoriality, concepts and delimitations are both contingent to forms of communication systems. I will distinguish between...

  4. The Circumpolar Arctic vegetation map (United States)

    Walker, Donald A.; Raynolds, Martha K.; Daniels, F.J.A.; Einarsson, E.; Elvebakk, A.; Gould, W.A.; Katenin, A.E.; Kholod, S.S.; Markon, C.J.; Melnikov, E.S.; Moskalenko, N.G.; Talbot, S. S.; Yurtsev, B.A.; Bliss, L.C.; Edlund, S.A.; Zoltai, S.C.; Wilhelm, M.; Bay, C.; Gudjonsson, G.; Ananjeva, G.V.; Drozdov, D.S.; Konchenko, L.A.; Korostelev, Y.V.; Ponomareva, O.E.; Matveyeva, N.V.; Safranova, I.N.; Shelkunova, R.; Polezhaev, A.N.; Johansen, B.E.; Maier, H.A.; Murray, D.F.; Fleming, Michael D.; Trahan, N.G.; Charron, T.M.; Lauritzen, S.M.; Vairin, B.A.


    Question: What are the major vegetation units in the Arctic, what is their composition, and how are they distributed among major bioclimate subzones and countries? Location: The Arctic tundra region, north of the tree line. Methods: A photo-interpretive approach was used to delineate the vegetation onto an Advanced Very High Resolution Radiometer (AVHRR) base image. Mapping experts within nine Arctic regions prepared draft maps using geographic information technology (ArcInfo) of their portion of the Arctic, and these were later synthesized to make the final map. Area analysis of the map was done according to bioclimate subzones, and country. The integrated mapping procedures resulted in other maps of vegetation, topography, soils, landscapes, lake cover, substrate pH, and above-ground biomass. Results: The final map was published at 1:7 500 000 scale map. Within the Arctic (total area = 7.11 x 106 km 2), about 5.05 ?? 106 km2 is vegetated. The remainder is ice covered. The map legend generally portrays the zonal vegetation within each map polygon. About 26% of the vegetated area is erect shrublands, 18% peaty graminoid tundras, 13% mountain complexes, 12% barrens, 11% mineral graminoid tundras, 11% prostrate-shrub tundras, and 7% wetlands. Canada has by far the most terrain in the High Arctic mostly associated with abundant barren types and prostrate dwarf-shrub tundra, whereas Russia has the largest area in the Low Arctic, predominantly low-shrub tundra. Conclusions: The CAVM is the first vegetation map of an entire global biome at a comparable resolution. The consistent treatment of the vegetation across the circumpolar Arctic, abundant ancillary material, and digital database should promote the application to numerous land-use, and climate-change applications and will make updating the map relatively easy. ?? IAVS; Opulus Press.

  5. The Arctic: The Physical Environment (United States)


    the northern coast of Russia, the Transpolar Route that crosses directly over the North Pole, and the Arctic Bridge that runs from Murmansk to... Murmansk , for example, is well known for being the largest deepwater port north of the Arctic Circle that is ice-free throughout the year.94...Online) Nuclear Icebreakers, Murmansk Shipping Company. Factsheet. (Accessed: August 3, 2004).; and Office

  6. Forecasters Handbook for the Arctic (United States)


    Arctic is the mountainous terrain. The * Aleutians extend for more than a thousand miles from the Alaskan Peninsula to Attu Island (Fig. 2-10). Unimak is... UNIMAK 10 ISLAND UNALASKA Figure 2-10. Alaska and the Aleutian Islands. 2-16 J NANSEN ALERT ,; SOUND AXEL INELLESIEE QUEEN/ ELIZABETH/ ISLANDSl GRE...received at Elmendorf Air Force Base on 11 May 1990. Arctic plume generation is apparent over Unimak Island in obvious close association with a polar

  7. Arctic Haze: Natural or Pollution? (United States)


    Atmospheric Environmet 15, 1407-1419. Barrie et al. (1985) have extended the original Berg W, W., Heidt L E, Pollock W, Sperry P. D., Cicerone R. historical...much more ive influences upon the surface-troposphere radiation widely than it was a few years ago, and is generally budget. Atmoshric Environmet 27...contributing to the March 1983 Arctic haze Alaskan Arctic, spring 1983. Atmospheric Environmet 19. episode. Atmospheric Environment 19, 2121-2126. 2159

  8. Interaction webs in arctic ecosystems

    DEFF Research Database (Denmark)

    Schmidt, Niels M.; Hardwick, Bess; Gilg, Olivier


    How species interact modulate their dynamics, their response to environmental change, and ultimately the functioning and stability of entire communities. Work conducted at Zackenberg, Northeast Greenland, has changed our view on how networks of arctic biotic interactions are structured, how they ...... that the combination of long-term, ecosystem-based monitoring, and targeted research projects offers the most fruitful basis for understanding and predicting the future of arctic ecosystems....

  9. Towards Prognostics for Electronics Components (United States)

    National Aeronautics and Space Administration — Electronics components have an increasingly critical role in avionics systems and in the development of future aircraft systems. Prognostics of such components is...

  10. Standardizing Research Methods for Prognostics (United States)

    National Aeronautics and Space Administration — Prognostics and health management (PHM) is a maturing system engineering discipline. As with most maturing disciplines, PHM does not yet have a universally accepted...

  11. Prognostic biomarkers in osteoarthritis (United States)

    Attur, Mukundan; Krasnokutsky-Samuels, Svetlana; Samuels, Jonathan; Abramson, Steven B.


    Purpose of review Identification of patients at risk for incident disease or disease progression in osteoarthritis remains challenging, as radiography is an insensitive reflection of molecular changes that presage cartilage and bone abnormalities. Thus there is a widely appreciated need for biochemical and imaging biomarkers. We describe recent developments with such biomarkers to identify osteoarthritis patients who are at risk for disease progression. Recent findings The biochemical markers currently under evaluation include anabolic, catabolic, and inflammatory molecules representing diverse biological pathways. A few promising cartilage and bone degradation and synthesis biomarkers are in various stages of development, awaiting further validation in larger populations. A number of studies have shown elevated expression levels of inflammatory biomarkers, both locally (synovial fluid) and systemically (serum and plasma). These chemical biomarkers are under evaluation in combination with imaging biomarkers to predict early onset and the burden of disease. Summary Prognostic biomarkers may be used in clinical knee osteoarthritis to identify subgroups in whom the disease progresses at different rates. This could facilitate our understanding of the pathogenesis and allow us to differentiate phenotypes within a heterogeneous knee osteoarthritis population. Ultimately, such findings may help facilitate the development of disease-modifying osteoarthritis drugs (DMOADs). PMID:23169101

  12. Multi-decadal effects of tides and Greenland glacial melting runoff on the ice, mixing and cross-shelf exchange in the Arctic Ocean. (United States)

    Luneva, Maria; Holt, Jason; Harle, James; Aksenov, Yevgeny


    We use a novel pan-Arctic sea ice-ocean coupled model to examine the effects of tides on sea ice and the mixing of water masses. Three 30-year simulations were performed: with explicitly resolved tides and the other without any tidal dynamics, with and without Greenland glacial melting runoff. We find that the tides are responsible for a 15% sea ice volume reduction during the last decade and also for changes in the salinity distribution, with surface salinity in the case with tides being on average 0.5-1.0 practical salinity units (PSU) higher than without tides. On the multi-decadal time scale tidal effects result in strong deflection of freshwater pathways of Siberian rivers in the Kara and Laptev Seas with surface salinity anomalies reaching 3-5 PSU compared with non-tidal case. Glacial Greenland melting runoff has a minor role in sea ice reduction. However, it results in fresh water barrier for deep convection in the Labrador Sea and strong reduction of deep water formation. Tides amplify this effect, presumably due to tidal transport of fresh waters from Greenland coastline to Labrador Sea. We evaluate shelf-deep ocean exchange fluxes: Ekman surface and bottom drains, eddy-induced and tidally induced offshore-onshore mass and buoyancy fluxes. It was found that cascading is a dominant process with a net cross-shelf transport about 1Sv, twice exceeding surface and benthic Ekman drains. Cascading is negatively correlated with surface Ekman drain, driven by wind.

  13. Time varying arctic climate change amplification

    Energy Technology Data Exchange (ETDEWEB)

    Chylek, Petr [Los Alamos National Laboratory; Dubey, Manvendra K [Los Alamos National Laboratory; Lesins, Glen [DALLHOUSIE U; Wang, Muyin [NOAA/JISAO


    During the past 130 years the global mean surface air temperature has risen by about 0.75 K. Due to feedbacks -- including the snow/ice albedo feedback -- the warming in the Arctic is expected to proceed at a faster rate than the global average. Climate model simulations suggest that this Arctic amplification produces warming that is two to three times larger than the global mean. Understanding the Arctic amplification is essential for projections of future Arctic climate including sea ice extent and melting of the Greenland ice sheet. We use the temperature records from the Arctic stations to show that (a) the Arctic amplification is larger at latitudes above 700 N compared to those within 64-70oN belt, and that, surprisingly; (b) the ratio of the Arctic to global rate of temperature change is not constant but varies on the decadal timescale. This time dependence will affect future projections of climate changes in the Arctic.

  14. The Arctic policy of China and Japan

    DEFF Research Database (Denmark)

    Tonami, Aki


    At the May 2013 Arctic Council Ministerial Meeting, five Asian states, namely China, Japan, India, Singapore and South Korea, were accepted to become new Permanent Observers at the Arctic Council. Nonetheless, little attention has been paid to the Asian states and their interest in the Arctic. Most...... discussions have focused on China and the assessment of China’s interest in the Arctic is divided. This paper attempts to fill this gap by presenting and comparing the various components of the Arctic policies of China and Japan. Referring to Putnam’s model of the “two-level game” and Young’s categorization...... of Arctic stakeholders’ interests, data from policy documents and interviews with relevant stakeholders were analysed. This analysis shows the Chinese and Japanese governments are in the gradual process of consolidating their Arctic policies, but both China and Japan see the Arctic less as a strategically...

  15. Mechanism of seasonal Arctic sea ice evolution and Arctic amplification

    Directory of Open Access Journals (Sweden)

    K.-Y. Kim


    Full Text Available Sea ice loss is proposed as a primary reason for the Arctic amplification, although the physical mechanism of the Arctic amplification and its connection with sea ice melting is still in debate. In the present study, monthly ERA-Interim reanalysis data are analyzed via cyclostationary empirical orthogonal function analysis to understand the seasonal mechanism of sea ice loss in the Arctic Ocean and the Arctic amplification. While sea ice loss is widespread over much of the perimeter of the Arctic Ocean in summer, sea ice remains thin in winter only in the Barents–Kara seas. Excessive turbulent heat flux through the sea surface exposed to air due to sea ice reduction warms the atmospheric column. Warmer air increases the downward longwave radiation and subsequently surface air temperature, which facilitates sea surface remains to be free of ice. This positive feedback mechanism is not clearly observed in the Laptev, East Siberian, Chukchi, and Beaufort seas, since sea ice refreezes in late fall (November before excessive turbulent heat flux is available for warming the atmospheric column in winter. A detailed seasonal heat budget is presented in order to understand specific differences between the Barents–Kara seas and Laptev, East Siberian, Chukchi, and Beaufort seas.

  16. Governance of protected areas in the Arctic

    Directory of Open Access Journals (Sweden)

    Timo Koivurova


    Full Text Available This article analyzes what has been achieved in the Arctic cooperation process – now functioning as the Arctic Council – as regards protected areas in the region. Specifically, the research examines how the work in two of the working groups of the Arctic Council has evolved – the Conservation of Arctic Flora and Fauna (CAFF and the Protection of the Arctic Marine Environment (PAME. Of particular interest here is CAFF’s Circumpolar Protected Area Network (CPAN, which is designed to coordinate the protected area policies of the Arctic states in their Arctic regions. The main goal of the article is to examine what kinds of functions CPAN is meant to achieve and to discuss whether the project has met its goals. An additional focus is the most recent development in the Arctic Council in the field of marine protected areas (MPAs, which were adopted as one priority action for another working group of the Council, the Protection of the Arctic Marine Environment. All of the developments discussed are evaluated by first identifying the trajectories of protected area activities in the Arctic Council and then discussing the possible ways forward. One salient consideration here is whether normative platforms other than the Arctic Council are better equipped to promote the work on protected areas in the Arctic and what type of policy focus for protected areas could be assumed in the Council.

  17. Interaction webs in arctic ecosystems: Determinants of arctic change? (United States)

    Schmidt, Niels M; Hardwick, Bess; Gilg, Olivier; Høye, Toke T; Krogh, Paul Henning; Meltofte, Hans; Michelsen, Anders; Mosbacher, Jesper B; Raundrup, Katrine; Reneerkens, Jeroen; Stewart, Lærke; Wirta, Helena; Roslin, Tomas


    How species interact modulate their dynamics, their response to environmental change, and ultimately the functioning and stability of entire communities. Work conducted at Zackenberg, Northeast Greenland, has changed our view on how networks of arctic biotic interactions are structured, how they vary in time, and how they are changing with current environmental change: firstly, the high arctic interaction webs are much more complex than previously envisaged, and with a structure mainly dictated by its arthropod component. Secondly, the dynamics of species within these webs reflect changes in environmental conditions. Thirdly, biotic interactions within a trophic level may affect other trophic levels, in some cases ultimately affecting land-atmosphere feedbacks. Finally, differential responses to environmental change may decouple interacting species. These insights form Zackenberg emphasize that the combination of long-term, ecosystem-based monitoring, and targeted research projects offers the most fruitful basis for understanding and predicting the future of arctic ecosystems.

  18. The Arctic tourism in Russia

    Directory of Open Access Journals (Sweden)

    Yury F. Lukin


    Full Text Available In the new book "Arctic tourism in Russia" the basic concepts, resource potential, attractiveness (from Lat. Attrahere: to attract, opportunities and threats of environmental, cruise, international, and other types of tourism in the Arctic are system-based analyzed, for the first time in the literature. The sphere of tourism has becoming an integral sector of the economy, having a multiplicative effect for the development of infrastructure, social services, employment. Reference materials about the tourism products in the Russian Arctic and Far North regions are published, including the Arkhangelsk and Murmansk regions; Republic of Karelia, Komi, Sakha (Yakutia; Nenets, the Yamalo-Nenets, Khanty-Mansiysk, the Chukotka Autonomous Districts; Taimyr Dolgan-Nenets Municipal District, Turukhansk district, the city of Norilsk of the Krasnoyarsk region; Magadan region, Kamchatka region.

  19. Arctic Basemaps In Google Maps

    DEFF Research Database (Denmark)

    Muggah, J.; Mioc, Darka


    The Ocean Mapping Group has been collecting data in the Arctic since 2003 and there are approximately 2,000 basemaps. In the current online storage format used by the OMG, it is difficult to view the data and users cannot easily pan and zoom. The purpose of this research is to investigate...... the advantages of the use of Google Maps, to display the OMG's Arctic data. The map should should load the large Artic dataset in a reasonable time. The bathymetric images were created using software in Linux written by the OMG, and a step-by-step process was used to create images from the multibeam data...... collected by the OMG in the Arctic. The website was also created using Linux operating system. The projection needed to be changed from Lambert Conformal Conic (useful at higher Latitudes) to Mercator (used by Google Maps) and the data needed to have a common colour scheme. After creating and testing...

  20. Singapore on the way to the Arctic

    Directory of Open Access Journals (Sweden)

    Valeriy P. Zhuravel


    Full Text Available Singapore’s Arctic interests and needs are analyzed. If China, Japan and South Korea consider the Arctic as a source of oil and gas, Singapore is interested not so much in the mineral resources of the region, but in the use of their technologies for their production. For Singapore, the Arctic is a platform on which its innovation and technology can find a place. Singapore has achieved the status of a permanent observer in the Arctic Council, which for him is a convenient position for careful monitoring of Arctic political changes.

  1. Circumpolar polynya regions and ice production in the Arctic: results from MODIS thermal infrared imagery from 2002/2003 to 2014/2015 with a regional focus on the Laptev Sea (United States)

    Preußer, Andreas; Heinemann, Günther; Willmes, Sascha; Paul, Stephan


    a distinct relation between increasing ice production and ice area export. Overall, our study presents a spatially highly accurate characterization of circumpolar polynya dynamics and ice production, which should be valuable for future modeling efforts of atmosphere-ice-ocean interactions in the Arctic.

  2. Arctic Energy Resources: Energy Research (United States)

    Gryc, George


    Arctic Energy Resources is a volume of 26 papers recording the proceedings of the Comite' Arctique International Conference, held at the Veritas Centre, Oslo, Norway, September 22-24, 1982. This was the fourth of a series of meetings on the Arctic organized by the Comite', an organization established in the Principality of Monaco with the active support of H.S.H. Prince Rainer III. The fourth Conference was opened by H.R.H. Crown Prins Harald of Norway, a noble beginning for a noble objective.The North Polar Region has drawn world attention recently because of several large hydrocarbon and other mineral discoveries and because of major political and environmental actions in the North American Arctic. Since 1923 when Naval Petroleum Reserve number 4 (NPR-4) was established, northern Alaska has been considered a major petroleum province. It was first explored systematically with modern techniques from 1943 to 1953. In 1958, Alaska became a state, and both federal and state lands in northern Alaska were available for private exploration. Building on the knowledge base provided by the Pet-4 program and its spinoff research laboratory at Barrow, industry explored the area east of NPR-4 and discovered the largest hydrocarbon accumulation (9.6 bbl crude oil and 26 Tcf (trillion cubic feet) gas) in North America at Prudhoe Bay. Concerns for environmental impacts, including oil spills, led to the passing of the National Environmental Policy Act in 1969. In 1970, over 9 million acres were set aside, now known as the Arctic National Wildlife Range, and in 1971 the Alaska Native Claims Settlement Act was passed by the U.S. Congress. The Arab oil embargo of 1973 heightened the energy crisis and changed the economic basis for further exploration in the Arctic. The convergence of these events dramatically changed the balance of power and the pace of activity in the North American Arctic.

  3. Arctic-Atlantic Climate Predictability provided by Poleward Ocean Heat Transport (United States)

    Årthun, Marius; Eldevik, Tor; Viste, Ellen; Drange, Helge; Furevik, Tore; Johnson, Helen L.; Keenlyside, Noel S.


    It is commonly understood that the potential for skillful climate prediction resides in the ocean. The poleward propagation of anomalous heat from the subpolar North Atlantic toward the Arctic Ocean has, in particular, been suggested as a primary source for predictability. It nevertheless remains unresolved how and to what extent variable ocean heat is imprinted on the atmosphere to realize its predictive potential over land. Here we assess from observations whether northwestern European and Arctic climate relates predictably to anomalous ocean heat in the Gulf Stream's northern extension. We show that variations in ocean temperature in the high latitude North Atlantic and Nordic Seas are reflected in the climate of northwestern Europe as well as in the Arctic sea ice extent. Statistical regression models show that climate variability thus can be skillfully predicted up to a decade in advance based on the state of the ocean. Our proposed prognostic framework provides an observationally based benchmark for dynamical prediction and highlights the North Atlantic-Nordic Seas as a key provider of a predictable Arctic-Atlantic climate.

  4. A Generic Software Architecture For Prognostics (United States)

    Teubert, Christopher; Daigle, Matthew J.; Sankararaman, Shankar; Goebel, Kai; Watkins, Jason


    Prognostics is a systems engineering discipline focused on predicting end-of-life of components and systems. As a relatively new and emerging technology, there are few fielded implementations of prognostics, due in part to practitioners perceiving a large hurdle in developing the models, algorithms, architecture, and integration pieces. As a result, no open software frameworks for applying prognostics currently exist. This paper introduces the Generic Software Architecture for Prognostics (GSAP), an open-source, cross-platform, object-oriented software framework and support library for creating prognostics applications. GSAP was designed to make prognostics more accessible and enable faster adoption and implementation by industry, by reducing the effort and investment required to develop, test, and deploy prognostics. This paper describes the requirements, design, and testing of GSAP. Additionally, a detailed case study involving battery prognostics demonstrates its use.

  5. Distributed Prognostics Based on Structural Model Decomposition (United States)

    National Aeronautics and Space Administration — Within systems health management, prognostics focuses on predicting the remaining useful life of a system. In the model-based prognostics paradigm, physics-based...

  6. Arctic Glass: Innovative Consumer Technology in Support of Arctic Research (United States)

    Ruthkoski, T.


    The advancement of cyberinfrastructure on the North Slope of Alaska is drastically limited by location-specific conditions, including: unique geophysical features, remoteness of location, and harsh climate. The associated cost of maintaining this unique cyberinfrastructure also becomes a limiting factor. As a result, field experiments conducted in this region have historically been at a technological disadvantage. The Arctic Glass project explored a variety of scenarios where innovative consumer-grade technology was leveraged as a lightweight, rapidly deployable, sustainable, alternatives to traditional large-scale Arctic cyberinfrastructure installations. Google Glass, cloud computing services, Internet of Things (IoT) microcontrollers, miniature LIDAR, co2 sensors designed for HVAC systems, and portable network kits are several of the components field-tested at the Toolik Field Station as part of this project. Region-specific software was also developed, including a multi featured, voice controlled Google Glass application named "Arctic Glass". Additionally, real-time sensor monitoring and remote control capability was evaluated through the deployment of a small cluster of microcontroller devices. Network robustness was analyzed as the devices delivered streams of abiotic data to a web-based dashboard monitoring service in near real time. The same data was also uploaded synchronously by the devices to Amazon Web Services. A detailed overview of solutions deployed during the 2015 field season, results from experiments utilizing consumer sensors, and potential roles consumer technology could play in support of Arctic science will be discussed.

  7. Changing Arctic ecosystems: ecology of loons in a changing Arctic (United States)

    Uher-Koch, Brian; Schmutz, Joel; Whalen, Mary; Pearce, John M.


    The U.S. Geological Survey (USGS) Changing Arctic Ecosystems (CAE) initiative informs key resource management decisions for Arctic Alaska by providing scientific information on current and future ecosystem response to a changing climate. From 2010 to 2014, a key study area for the USGS CAE initiative has been the Arctic Coastal Plain of northern Alaska. This region has experienced rapid warming during the past 30 years, leading to the thawing of permafrost and changes to lake and river systems. These changes, and projections of continued change, have raised questions about effects on wildlife populations that rely on northern lake ecosystems, such as loons. Loons rely on freshwater lakes for nesting habitat and the fish and invertebrates inhabiting the lakes for food. Loons live within the National Petroleum Reserve-Alaska (NPR-A) on Alaska’s northern coast, where oil and gas development is expected to increase. Research by the USGS examines how breeding loons use the Arctic lake ecosystem and the capacity of loons to adapt to future landscape change.

  8. Relevance of Volcanic Eruptions for Decadal to Centennial Fluctuations of the Last Millennium's Arctic Sea Ice Extent (United States)

    Slawinska, J. M.; Robock, A.; Zambri, B.; Xia, L.


    Both external forcings (solar radiation, volcanic eruptions) and internal fluctuations have been proposed to explain such multi-centennial perturbations as the Little Ice Age. Confidence in these hypotheses is limited due to the high uncertainty and limited number of proxies, as well as only one observed realization of the Last Millennium. Here, we evaluate different hypotheses on the origin of Little Ice Age-like anomalies, focusing in particular on the long-term response of North Atlantic and Arctic climate perturbations to solar and volcanic perturbations. For that, we analyze the Last Millennium Ensemble of climate model simulations carried out with the Community Earth System Model (CESM) at the National Center for Atmospheric Research, supplemented with a range of sensitivity tests performed by us using CESM. We identify possible factors favouring the particular phase of the Atlantic Multidecadal Oscillation (AMO) and its interactions with other multi-centennial modes of cooling and glaciation, focusing in particular on sensitivity to such initial conditions as the strength of solar and volcanic forcing. By comparing the climate response to various combinations of external perturbations, we demonstrate nonlinear interactions that are necessary to explain trends observed in the fully coupled system and discuss physical mechanisms through which these external forcings can trigger such multidecadal modes of variability as AMO and subsequently lead to a Little Ice Age-like regime. For that, we capture and compare patterns of the coupled atmosphere-sea-ice-ocean response as revealed through a range of data analysis techniques. We show that the large 1257 Samalas, 1452 Kuwae, and 1600 Huaynaputina volcanic eruptions were the main causes of the multi-centennial glaciation associated with the Little Ice Age.

  9. Cytogenetic Prognostication Within Medulloblastoma Subgroups (United States)

    Shih, David J.H.; Northcott, Paul A.; Remke, Marc; Korshunov, Andrey; Ramaswamy, Vijay; Kool, Marcel; Luu, Betty; Yao, Yuan; Wang, Xin; Dubuc, Adrian M.; Garzia, Livia; Peacock, John; Mack, Stephen C.; Wu, Xiaochong; Rolider, Adi; Morrissy, A. Sorana; Cavalli, Florence M.G.; Jones, David T.W.; Zitterbart, Karel; Faria, Claudia C.; Schüller, Ulrich; Kren, Leos; Kumabe, Toshihiro; Tominaga, Teiji; Shin Ra, Young; Garami, Miklós; Hauser, Peter; Chan, Jennifer A.; Robinson, Shenandoah; Bognár, László; Klekner, Almos; Saad, Ali G.; Liau, Linda M.; Albrecht, Steffen; Fontebasso, Adam; Cinalli, Giuseppe; De Antonellis, Pasqualino; Zollo, Massimo; Cooper, Michael K.; Thompson, Reid C.; Bailey, Simon; Lindsey, Janet C.; Di Rocco, Concezio; Massimi, Luca; Michiels, Erna M.C.; Scherer, Stephen W.; Phillips, Joanna J.; Gupta, Nalin; Fan, Xing; Muraszko, Karin M.; Vibhakar, Rajeev; Eberhart, Charles G.; Fouladi, Maryam; Lach, Boleslaw; Jung, Shin; Wechsler-Reya, Robert J.; Fèvre-Montange, Michelle; Jouvet, Anne; Jabado, Nada; Pollack, Ian F.; Weiss, William A.; Lee, Ji-Yeoun; Cho, Byung-Kyu; Kim, Seung-Ki; Wang, Kyu-Chang; Leonard, Jeffrey R.; Rubin, Joshua B.; de Torres, Carmen; Lavarino, Cinzia; Mora, Jaume; Cho, Yoon-Jae; Tabori, Uri; Olson, James M.; Gajjar, Amar; Packer, Roger J.; Rutkowski, Stefan; Pomeroy, Scott L.; French, Pim J.; Kloosterhof, Nanne K.; Kros, Johan M.; Van Meir, Erwin G.; Clifford, Steven C.; Bourdeaut, Franck; Delattre, Olivier; Doz, François F.; Hawkins, Cynthia E.; Malkin, David; Grajkowska, Wieslawa A.; Perek-Polnik, Marta; Bouffet, Eric; Rutka, James T.; Pfister, Stefan M.; Taylor, Michael D.


    Purpose Medulloblastoma comprises four distinct molecular subgroups: WNT, SHH, Group 3, and Group 4. Current medulloblastoma protocols stratify patients based on clinical features: patient age, metastatic stage, extent of resection, and histologic variant. Stark prognostic and genetic differences among the four subgroups suggest that subgroup-specific molecular biomarkers could improve patient prognostication. Patients and Methods Molecular biomarkers were identified from a discovery set of 673 medulloblastomas from 43 cities around the world. Combined risk stratification models were designed based on clinical and cytogenetic biomarkers identified by multivariable Cox proportional hazards analyses. Identified biomarkers were tested using fluorescent in situ hybridization (FISH) on a nonoverlapping medulloblastoma tissue microarray (n = 453), with subsequent validation of the risk stratification models. Results Subgroup information improves the predictive accuracy of a multivariable survival model compared with clinical biomarkers alone. Most previously published cytogenetic biomarkers are only prognostic within a single medulloblastoma subgroup. Profiling six FISH biomarkers (GLI2, MYC, chromosome 11 [chr11], chr14, 17p, and 17q) on formalin-fixed paraffin-embedded tissues, we can reliably and reproducibly identify very low-risk and very high-risk patients within SHH, Group 3, and Group 4 medulloblastomas. Conclusion Combining subgroup and cytogenetic biomarkers with established clinical biomarkers substantially improves patient prognostication, even in the context of heterogeneous clinical therapies. The prognostic significance of most molecular biomarkers is restricted to a specific subgroup. We have identified a small panel of cytogenetic biomarkers that reliably identifies very high-risk and very low-risk groups of patients, making it an excellent tool for selecting patients for therapy intensification and therapy de-escalation in future clinical trials. PMID

  10. ESPC Regional Arctic Prediction System (United States)


    improvement efforts easier. 2. Establish Collaboration with University of Alaska at Fairbanks (UAF) In July 22-24, we visited UAF Geophysical...detailed steps toward full collaborations. a) Land surface- permafrost modeling. Permafrost is an important part of Arctic Cryosphere. UAF/GI has very

  11. Geologic Provinces of the Circum-Arctic, 2008 (north of the Arctic Circle) (United States)

    U.S. Geological Survey, Department of the Interior — This shapefile includes arcs and polygons that describe U.S. Geological Survey defined 33 geologic provinces of the Circum-Arctic (north of the Arctic Circle). Each...

  12. 77 FR 31677 - Request for Public Comment on Interagency Arctic Research Policy Committee (IARPC) Arctic... (United States)


    ... From the Federal Register Online via the Government Publishing Office OFFICE OF SCIENCE AND TECHNOLOGY POLICY Request for Public Comment on Interagency Arctic Research Policy Committee (IARPC) Arctic... and Policy Act of 1984 (ARPA), Public Law 98-373, established the Interagency Arctic Research Policy...

  13. Arctic fourth world nations in a geopolitical dance

    National Research Council Canada - National Science Library

    Bruce, Heidi


    .... Deeply affected by this increased northern exposure are Arctic Fourth World nations - politically and culturally distinct nations encapsulated by states - that have lived in the Arctic for millennia...

  14. Analytic prognostic for petrochemical pipelines

    CERN Document Server

    Jaoude, Abdo Abou; El-Tawil, Khaled; Noura, Hassan; Ouladsine, Mustapha


    Pipelines tubes are part of vital mechanical systems largely used in petrochemical industries. They serve to transport natural gases or liquids. They are cylindrical tubes and are submitted to the risks of corrosion due to high PH concentrations of the transported liquids in addition to fatigue cracks due to the alternation of pressure-depression of gas along the time, initiating therefore in the tubes body micro-cracks that can propagate abruptly to lead to failure. The development of the prognostic process for such systems increases largely their performance and their availability, as well decreases the global cost of their missions. Therefore, this paper deals with a new prognostic approach to improve the performance of these pipelines. Only the first mode of crack, that is, the opening mode, is considered.

  15. Prognostic stratification of ulcerated melanoma

    DEFF Research Database (Denmark)

    Bønnelykke-Behrndtz, Marie L; Schmidt, Henrik; Christensen, Ib J


    OBJECTIVES: For patients with melanoma, ulceration is an important prognostic marker and interestingly also a predictive marker for the response of adjuvant interferon. A consensual definition and accurate assessment of ulceration are therefore crucial for proper staging and clinical management. We...... stratification of ulcerated lesions. METHODS: From H&E-stained sections, the status (presence vs absence), extent (percentage of the total tumor length), and type (infiltrative vs attenuative) of ulceration and epidermal involvement were evaluated from 385 patients with cutaneous melanoma. RESULTS: The presence...... of ulceration (hazard ratio [HR], 1.83), an attenuative type of ulceration (HR, 3.02), and excessive ulceration (HR, 3.57) were independent predictors of poor melanoma-specific survival. Further subdivision of minimal/moderate ulceration showed independent prognostic value only for lesions with epidermal...

  16. Arctic pathways of Pacific Water: Arctic Ocean Model Intercomparison experiments (United States)

    Karcher, Michael; Proshutinsky, Andrey; Gerdes, Rüdiger; de Cuevas, Beverly; Golubeva, Elena; Kauker, Frank; Nguyen, An T.; Platov, Gennady A.; Wadley, Martin; Watanabe, Eiji; Coward, Andrew C.; Nurser, A. J. George


    Abstract Pacific Water (PW) enters the Arctic Ocean through Bering Strait and brings in heat, fresh water, and nutrients from the northern Bering Sea. The circulation of PW in the central Arctic Ocean is only partially understood due to the lack of observations. In this paper, pathways of PW are investigated using simulations with six state‐of‐the art regional and global Ocean General Circulation Models (OGCMs). In the simulations, PW is tracked by a passive tracer, released in Bering Strait. Simulated PW spreads from the Bering Strait region in three major branches. One of them starts in the Barrow Canyon, bringing PW along the continental slope of Alaska into the Canadian Straits and then into Baffin Bay. The second begins in the vicinity of the Herald Canyon and transports PW along the continental slope of the East Siberian Sea into the Transpolar Drift, and then through Fram Strait and the Greenland Sea. The third branch begins near the Herald Shoal and the central Chukchi shelf and brings PW into the Beaufort Gyre. In the models, the wind, acting via Ekman pumping, drives the seasonal and interannual variability of PW in the Canadian Basin of the Arctic Ocean. The wind affects the simulated PW pathways by changing the vertical shear of the relative vorticity of the ocean flow in the Canada Basin. PMID:27818853

  17. Arctic Research Plan: FY2017-2021 (United States)

    Starkweather, Sandy; Jeffries, Martin O; Stephenson, Simon; Anderson, Rebecca D.; Jones, Benjamin M.; Loehman, Rachel A.; von Biela, Vanessa R.


    The United States is an Arctic nation—Americans depend on the Arctic for biodiversity and climate regulation and for natural resources. America’s Arctic—Alaska—is at the forefront of rapid climate, environmental, and socio-economic changes that are testing the resilience and sustainability of communities and ecosystems. Research to increase fundamental understanding of these changes is needed to inform sound, science-based decision- and policy-making and to develop appropriate solutions for Alaska and the Arctic region as a whole. Created by an Act of Congress in 1984, and since 2010 a subcommittee of the National Science and Technology Council (NSTC) in the Executive Office of the President, the Interagency Arctic Research Policy Committee (IARPC) plays a critical role in advancing scientific knowledge and understanding of the changing Arctic and its impacts far beyond the boundaries of the Arctic. Comprising 14 Federal agencies, offices, and departments, IARPC is responsible for the implementation of a 5-year Arctic Research Plan in consultation with the U.S. Arctic Research Commission, the Governor of the State of Alaska, residents of the Arctic, the private sector, and public interest groups.

  18. Plate tectonic history of the Arctic (United States)

    Burke, K.


    Tectonic development of the Arctic Ocean is outlined, and geological maps are provided for the Arctic during the mid-Cenozoic, later Cretaceous, late Jurassic, early Cretaceous, early Jurassic and late Devonian. It is concluded that Arctic basin history is moulded by the events of the following intervals: (1) continental collision and immediately subsequent rifting and ocean formation in the Devonian, and continental rifting ocean formation, rapid rotation of microcontinents, and another episode of collision in the latest Jurassic and Cretaceous. It is noted that Cenozoic Arctic basin formation is a smaller scale event superimposed on the late Mesozoic ocean basin.

  19. Oil Tanker Transportation In The Russian Arctic

    Directory of Open Access Journals (Sweden)

    Konygin A.


    Full Text Available Abstract High hydrocarbon resource potential makes the Russian Arctic an attractive region for major oil and gas producing companies. Any investment decision is commonly based on an assessment stage which includes various types of technical and economical evaluations. Transportation cost in the Russian Arctic drastically influences overall project economics. Thus accurate method for transportation cost assessment becomes important from early stages of project definition. Infrastructure in the Russian Arctic is poorly developed so conventional estimation methods of hydrocarbon transportation tariff are ineffective. This paper describes a cost estimation method for tanker transportation of oil which considers key features of operations in the Russian Arctic.

  20. SCICEX: Submarine Arctic Science Program, Version 1 (United States)

    National Aeronautics and Space Administration — The Submarine Arctic Science Program, SCICEX, is a federal interagency collaboration among the operational Navy, research agencies, and the marine research community...

  1. China's Developing Arctic Policies: Myths and Misconceptions

    Directory of Open Access Journals (Sweden)

    Marc Lanteigne


    Full Text Available The Arctic and Far North regions of the world have grown in importance for China's international interests in recent years, and in 2013 China became an observer state in the Arctic Council. Beijing has sought to develop an Arctic policy based on scientific research and partnerships, including in the areas of environmental studies and climate change issues, as well as development and economic issues. As the Arctic gains more international attention due to the effects of ice melting and the possibility of the region becoming a new source of resources, concerns have been raised about a scramble for riches and economic advantages. China, as a rising political and economic power, has been subject to much scrutiny, especially from the West, about its emerging agenda in the Arctic region. Although China is not an Arctic state, the concerns are based on predictions that Beijing is seeking to play a stronger and perhaps even dominant role in the Arctic, and this has led to many misconceptions about China's Arctic policy. The result has been a "clash of identities" between Chinese and Western perceptions, and in order to understand why these diverging views have appeared, it is necessary to first examine the origins of "myths" about China's regional Arctic policies, and then examine their roles, using constructivist theory, before suggesting ways for both China and the international community to address this divergence.

  2. Singapore on the way to the Arctic


    Valeriy P. Zhuravel; Artem P. Danilov


    Singapore’s Arctic interests and needs are analyzed. If China, Japan and South Korea consider the Arctic as a source of oil and gas, Singapore is interested not so much in the mineral resources of the region, but in the use of their technologies for their production. For Singapore, the Arctic is a platform on which its innovation and technology can find a place. Singapore has achieved the status of a permanent observer in the Arctic Council, which for him is a convenient position for careful ...

  3. Arctic tides from GPS on sea ice

    DEFF Research Database (Denmark)

    Kildegaard Rose, Stine; Skourup, Henriette; Forsberg, René

    The presence of sea-ice in the Arctic Ocean plays a significant role in the Arctic climate. Sea ice dampens the ocean tide amplitude with the result that global tidal models which use only astronomical data perform less accurately in the polar regions. This study presents a kinematic processing...... of Global Positioning System (GPS) buoys placed on sea-ice at five different sites north of Greenland for the study of sea level height and tidal analysis to improve tidal models in the Central Arctic. The GPS measurements are compared with the Arctic tidal model AOTIM-5, which assimilates tide...

  4. International dialogue about people in the Arctic: the topic of development of the human capital at the International Arctic Forum "Arctic: Territory of Dialogue"

    Directory of Open Access Journals (Sweden)

    Igor V. Katorin


    Full Text Available The International Arctic Forum “Arctic: Territory of Dialogue", held at the end of March 2017 in Arkhangelsk, has become one of the most representative events devoted to the Arctic issues in Russia in recent years. The business program of the event included a plenary session with the participation of the Presidents of Russia, Finland, Iceland, as well as 13 thematic sessions. The theme of the forum "People in the Arctic" was most actively discussed at four thematic sessions, as well as at the special event — the Forum of the Arctic Municipalities. The article presents the main results of the discussion of the participants of the event at the sessions "The Arctic is the territory of professionals", "The Arctic is the Territory of History, Culture and Tourism", "The Arctic is the Territory of Health", "The Arctic is the Territory of the Favorable Life Environment", and also at the Forum of the Arctic Municipalities.

  5. Interaction webs in arctic ecosystems

    DEFF Research Database (Denmark)

    Schmidt, Niels Martin; Hardwick, Bess; Gilg, Olivier


    in environmental conditions. Thirdly, biotic interactions within a trophic level may affect other trophic levels, in some cases ultimately affecting land–atmosphere feedbacks. Finally, differential responses to environmental change may decouple interacting species. These insights form Zackenberg emphasize......How species interact modulate their dynamics, their response to environmental change, and ultimately the functioning and stability of entire communities. Work conducted at Zackenberg, Northeast Greenland, has changed our view on how networks of arctic biotic interactions are structured, how...... they vary in time, and how they are changing with current environmental change: firstly, the high arctic interaction webs are much more complex than previously envisaged, and with a structure mainly dictated by its arthropod component. Secondly, the dynamics of species within these webs reflect changes...

  6. Building Materials in Arctic Climate

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede


    Building in the artic requires special attention on the appropriateness of building materials. The harsh climate makes execution difficult and sets unusual requirements for the pure material properties. In addition, there is a lack of choice of good, natural building materials in the arctic....... This results in high transport costs. The building materials situation in Greenland may potentially be improved by intensifying the reuse of building materials or by promoting the local production of building materials....

  7. Arctic Haze: Natural or Pollution? (United States)


    occur in specific minerals which strongly resist weathering. An example would be zircons , which contain zirconium and hafnium . If this is correct, and if...the YMEF in August and September 1980. A summary of Mr. Borys’ field work to date is shown in Table 1. Samples were collected during approximately 10...XRF microprobe. -1.1- Table 1. Summary of field studies of cloud-active aerosol in the Arctic and environs. Site Dates , Number of 24-h samples Barrow

  8. Arctic Haze: Natural or Pollution (United States)


    l’Atlantique. Sur la base de mesures d’opacite’ et du modele de transport propose une estimation de 1’emmxission totale du Sahara est presentee . This work took more than 6 months, and represented a considerable cost -free contribution to our project. Methods used were dry sieving and...communications associated with the proposed Arctic Network. The filter samples will cost this project nothing; the aerosol vertical profiles will be

  9. Can Canada Avoid Arctic Militarization? (United States)


    global market and the evolution of new fracking technology for the extraction of shale hydrocarbons, the development of the Canadian Arctic might not...Powers and Prospects in Canada’s North, ed. Abele Frances (Montréal: Institute for Research on Public Policy, 2009), 378. 167Richard Spencer, “ Fracking ...Boom Frees the US from Old Oil Alliances,” The Telegraph, December 13, 2013, Fracking -boom-frees

  10. Remote sensing data assimilation for a prognostic phenology model

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, Peter E [ORNL; Stockli, Reto [Colorado State University, Fort Collins


    Predicting the global carbon and water cycle requires a realistic representation of vegetation phenology in climate models. However most prognostic phenology models are not yet suited for global applications, and diagnostic satellite data can be uncertain and lack predictive power. We present a framework for data assimilation of Fraction of Photosynthetically Active Radiation absorbed by vegetation (FPAR) and Leaf Area Index (LAI) from the MODerate Resolution Imaging Spectroradiometer (MODIS) to constrain empirical temperature, light, moisture and structural vegetation parameters of a prognostic phenology model. We find that data assimilation better constrains structural vegetation parameters than climate control parameters. Improvements are largest for drought-deciduous ecosystems where correlation of predicted versus satellite-observed FPAR and LAI increases from negative to 0.7-0.8. Data assimilation effectively overcomes the cloud- and aerosol-related deficiencies of satellite data sets in tropical areas. Validation with a 49-year-long phenology data set reveals that the temperature-driven start of season (SOS) is light limited in warm years. The model has substantial skill (R = 0.73) to reproduce SOS inter-annual and decadal variability. Predicted SOS shows a higher inter-annual variability with a negative bias of 5-20 days compared to species-level SOS. It is however accurate to within 1-2 days compared to SOS derived from net ecosystem exchange (NEE) measurements at a FLUXNET tower. The model only has weak skill to predict end of season (EOS). Use of remote sensing data assimilation for phenology model development is encouraged but validation should be extended with phenology data sets covering mediterranean, tropical and arctic ecosystems.

  11. Characterizing Arctic aerosol in the high an low Arctic during NETCARE 2015 (United States)

    Burkart, Julia; Willis, Megan; Bozem, Heiko; Kunkel, Daniel; Hoor, Peter; Schulz, Hannes; Herber, Andreas; Hannah, Sarah; Leaitch, Richard; Abbatt, Jon


    The Arctic aerosol is well known to show distinct seasonal variations with a maximum in aerosol mass concentrations during late winter and early spring referred to as Arctic haze. To characterize the Arctic haze phenomenon and related processes extensive aerosol measurements (particle number and size, aerosol composition and black carbon, and trace gases) were conducted from the Polar 6 aircraft (Alfred Wegener Institute, Germany) in April 2015. The campaign covered locations in the high Arctic (Alert and Eureka) and low Arctic (Inuvik). Flights focused on vertical profiles from 60m agl up to 6 km. We present the vertical distribution of aerosol number concentrations in different size ranges (5nm to 1µm), black carbon mass concentrations and CO mixing ratios at these three locations. Differences between the high and low Arctic will be highlighted and discussed together with 10 days FLEXPART back trajectories. Air masses in the low Arctic were dominated by a distinct pollution layer tracing back to sources in Northern China, while air masses observed in the high Arctic were less polluted and exhibited a longer residence time (up to 10 days) within the Arctic. We show that there is evidence for black carbon deposition in the high Arctic boundary layer. A decrease in black carbon mass concentrations was frequently observed within the lowest 1000m of the high Arctic atmosphere.

  12. Generic Software Architecture for Prognostics (GSAP) User Guide (United States)

    Teubert, Christopher Allen; Daigle, Matthew John; Watkins, Jason; Sankararaman, Shankar; Goebel, Kai


    The Generic Software Architecture for Prognostics (GSAP) is a framework for applying prognostics. It makes applying prognostics easier by implementing many of the common elements across prognostic applications. The standard interface enables reuse of prognostic algorithms and models across systems using the GSAP framework.

  13. Arctic Change Information for a Broad Audience (United States)

    Soreide, N. N.; Overland, J. E.; Calder, J.


    Demonstrable environmental changes have occurred in the Arctic over the past three decades. NOAA's Arctic Theme Page is a rich resource web site focused on high latitude studies and the Arctic, with links to widely distributed data and information focused on the Arctic. Included is a collection of essays on relevant topics by experts in Arctic research. The website has proven useful to a wide audience, including scientists, students, teachers, decision makers and the general public, as indicated through recognition by USA Today, Science magazine, etc. ( Working jointly with NSF and the University of Washington's Polar Science Center as part of the Study of Environmental Arctic Change (SEARCH) program, NOAA has developed a website for access to pan-Arctic time series spanning diverse data types including climate indices, atmospheric, oceanic, sea ice, terrestrial, biological and fisheries. Modest analysis functions and more detailed analysis results are provided. ( This paper will describe development of an Artic Change Detection status website to provide a direct and comprehensive view of previous and ongoing change in the Arctic for a broad climate community. For example, composite metrics are developed using principal component analysis based on 86 multivariate pan-Arctic time series for seven data types. Two of these metrics can be interpreted as a regime change/trend component and an interdecadal component. Changes can also be visually observed through tracking of 28 separate biophysical indicators. Results will be presented in the form of a web site with relevant, easily understood, value-added knowledge backed by peer review from Arctic scientists and scientific journals.

  14. Modelling micro- and macrophysical contributors to the dissipation of an Arctic mixed-phase cloud during the Arctic Summer Cloud Ocean Study

    National Research Council Canada - National Science Library

    Loewe, Katharina; Ekman, Annica M. L; Paukert, Marco; Sedlar, Joseph; Tjernström, Michael; Hoose, Corinna


    The Arctic climate is changing; temperature changes in the Arctic are greater than at midlatitudes, and changing atmospheric conditions influence Arctic mixed-phase clouds, which are important for the Arctic surface energy budget...

  15. Metrics for Evaluating Performance of Prognostic Techniques (United States)

    National Aeronautics and Space Administration — Prognostics is an emerging concept in condition basedmaintenance(CBM)ofcriticalsystems.Alongwith developing the fundamentals of being able to confidently predict...

  16. Health Monitoring and Prognostics for Computer Servers (United States)

    National Aeronautics and Space Administration — Abstract Prognostics solutions for mission critical systems require a comprehensive methodology for proactively detecting and isolating failures, recommending and...

  17. Embedded Diagnostics & Prognostics Wireless Sensing Platforms

    National Research Council Canada - National Science Library

    Ousachi, Mark; Scott, Andrew; Yee, David; Hosmer, Thomas; Daniszewski, Dave


    An embedded diagnostics and prognostics architecture affects several aspects associated with military ground vehicles such as improved safety, reduction in maintenance times, weapon system readiness...


    National Aeronautics and Space Administration — This paper introduces a generic distributed prognostic health management (PHM) architecture with specific application to the electrical power systems domain. Current...

  19. Simulating Degradation Data for Prognostic Algorithm Development (United States)

    National Aeronautics and Space Administration — PHM08 Challenge Dataset is now publicly available at the NASA Prognostics Respository + Download INTRODUCTION - WHY SIMULATE DEGRADATION DATA? Of various challenges...

  20. A Survey of Artificial Intelligence for Prognostics (United States)

    National Aeronautics and Space Administration — Integrated Systems Health Management includes as key elements fault detection, fault diagnostics, and failure prognostics. Whereas fault detection and diagnostics...

  1. Clinical and Histopathological Prognostic Factors in Chondrosarcomas

    Directory of Open Access Journals (Sweden)

    Bjarne Lund


    Full Text Available Purpose. In an attempt to identify clinical and histopathological factors of prognostic importance in chondrosarcomas, 115 cases of malignant and borderline chondromatous tumours were reviewed.

  2. Benefit-sharing arrangements in the Arctic

    NARCIS (Netherlands)

    Tysyachnyouk, M.


    Can the interests of both the extractive industries and Indigenous communities in the Arctic be balanced through the implementation of benefit-sharing practices in the places of resource extraction? Most transnational corporations
    in the Arctic oil and gas sector have declared their commitment

  3. Recent Arctic Sea Level Variations from Satellites

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Piccioni, Gaia


    Sea level monitoring in the Arctic region has always been an extreme challenge for remote sensing, and in particular for satellite altimetry. Despite more than two decades of observations, altimetry is still limited in the inner Arctic Ocean. We have developed an updated version of the Danish Tec...

  4. Politics of sustainability in the Arctic (POSUSA)

    DEFF Research Database (Denmark)

    Gad, Ulrik Pram; Jakobsen, Uffe; Strandsbjerg, Jeppe

    elaborated than a definable term with a specific meaning. This is the core hypothesis in a collective research project, the POSUSA project (Politics of Sustainability in the Arctic) that aims to map and analyse the role of sustainability in various political and economic strategies in the Arctic....

  5. Arctic-like Rabies Virus, Bangladesh


    Jamil, Khondoker Mahbuba; AHMED, Kamruddin; Hossain, Moazzem; Matsumoto, Takashi; Ali, Mohammad Azmat; Hossain, Sohrab; Hossain, Shakhawat; Islam, Aminul; Nasiruddin, Mohammad; Nishizono, Akira


    Arctic/Arctic-like rabies virus group 2 spread into Bangladesh ?32 years ago. Because rabies is endemic to and a major public health problem in this country, we characterized this virus group. Its glycoprotein has 3 potential N-glycosylation sites that affect viral pathogenesis. Diversity of rabies virus might have public health implications in Bangladesh.

  6. Arctic freshwater export: Status, mechanisms, and prospects

    NARCIS (Netherlands)

    Haine, T.W.N.; Curry, B.; Gerdes, R.; Hansen, E.; Karcher, M.; Lee, C.; Rudels, B.; Spreen, G.; de Steur, L.; Stewart, K.D.; Woodgate, R.


    Large freshwater anomalies clearly exist in the Arctic Ocean. For example, liquid freshwater has accumulated in the Beaufort Gyre in the decade of the 2000s compared to 1980–2000, with an extra ˜ 5000 km3 — about 25% — being stored. The sources of freshwater to the Arctic from precipitation and

  7. Towards a rain-dominated Arctic (United States)

    Bintanja, Richard; Andry, Olivier


    Current climate models project a strong increase in Arctic precipitation over the coming century, which has been attributed primarily to enhanced surface evaporation associated with sea-ice retreat. Since the Arctic is still quite cold, especially in winter, it is often (implicitly) assumed that the additional precipitation will fall mostly as snow. However, very little is known about future changes in rain/snow distribution in the Arctic, notwithstanding the importance for hydrology and biology. Here we use 37 state-of-the-art climate models in standardised twenty-first-century (2006-2100) simulations to show that 70° - 90°N average annual Arctic snowfall will actually decrease, despite the strong increase in precipitation, and that most of the additional precipitation in the future (2091-2100) will fall as rain. In fact, rain is even projected to become the dominant form of precipitation in the Arctic region. This is because Arctic atmospheric warming causes a greater fraction of snowfall to melt before it reaches the surface, in particular over the North Atlantic and the Barents Sea. The reduction in Arctic snowfall is most pronounced during summer and autumn when temperatures are close to the melting point, but also winter rainfall is found to intensify considerably. Projected (seasonal) trends in rain/snowfall will heavily impact Arctic hydrology (e.g. river discharge, permafrost melt), climatology (e.g. snow, sea ice albedo and melt) and ecology (e.g. water and food availability).

  8. Towards a rain-dominated Arctic

    NARCIS (Netherlands)

    Bintanja, Richard; Andry, Olivier


    Climate models project a strong increase in Arctic precipitation over the coming century1, which has been attributed primarily to enhanced surface evaporation associated with sea-ice retreat2. Since the Arctic is still quite cold, especially in winter, it is often (implicitly) assumed that the

  9. Arctic decadal variability in a warming world

    NARCIS (Netherlands)

    Linden, van der Eveline C.; Bintanja, Richard; Hazeleger, Wilco


    Natural decadal variability of surface air temperature might obscure Arctic temperature trends induced by anthropogenic forcing. It is therefore imperative to know how Arctic decadal variability (ADV) will change as the climate warms. In this study, we evaluate ADV characteristics in three

  10. Arctic Climate Observations Using Underwater Sound (ACOUS) (United States)


    of the ice cover in the Arctic Ocean. ACOUS will provide data on the large thermohaline change now occurring in the Arctic Ocean, and advance UAF for a simulation period of 47 years. Two general regimes of circulation with a 15-year period were discovered . Anti-cyclonic circulation

  11. Pacific Northwest Laboratory Alaska (ARCTIC) research program

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, W.C.; Eberhardt, L.E.


    The current program continues studies of arctic ecosystems begun in 1959 as part of the Cape Thompson Program. Specific ecosystem aspects include studies of the ecology of arctic and red foxes, small mammel and bird population studies, lichen studies, and radiation ecology studies. (ACR)


    Directory of Open Access Journals (Sweden)

    Natalia Valerievna Eremina


    Full Text Available The aim of the article is to reveal the forms, methods, content of British strategy in Arctic. Arctic is becoming the area of international cooperation among, first of all, Arctic states. Britain has ambitions to get the status of so-called “subarctic state” to prove its international leadership and acquire guarantees of energetic security. Now Britain has been elaborating the two strategies: military and scientific ones. The main instrument to solve the tasks for Britain is to participate in international structures, connected with Arctic. The article pays attention to the aspects that were not previously analyzed, such as: reasons of British interests in Arctic, bilateral and multilateral relationships between Britain and its partners, first of all, cooperation between Russia and Britain; British institutions; positive and negative aspects of British Arctic strategy; factors that have impact on its evolution, mainly EU and Scottish factors. The research allowed to make the conclusion that Britain does not have enough instruments to have a strong disposition in Arctic, though it plans to accelerate its participation in Arctic organizations. The article is based upon system and structural analysis.

  13. Fate of mercury in the Arctic (FOMA)

    DEFF Research Database (Denmark)

    Skov, H.; Christensen, J.; Asmund, G.

    This report is the final reporting of the project FONA, funded by the Danish Environmental Protection Agency with means from the MIKA/DANCEA funds for Environmental Support to the Arctic Region. The aim of the project is to study the intercompartment mercury transport chain in the arctic area. From...

  14. International Regulation of Central Arctic Ocean Fisheries

    NARCIS (Netherlands)

    Molenaar, E.J.

    Due in particular to the impacts of climate change, the adequacy of the international regulation of Central Arctic Ocean fisheries has come under increasing scrutiny in recent years. As shown in this article, however, international regulation of Central Arctic Ocean fisheries is by no means entirely

  15. Prognostic Factors in Hodgkin's Disease

    DEFF Research Database (Denmark)



    Prognostic factors in Hodgkin's disease (HD) are reviewed. The Ann Arbor staging classification remains the basis for evaluation of patients with HD. However, subgroups of patients with differing prognoses exist within the individual stages. In pathological stages I and II, the number of involved...... of extent of disease such as erythrocyte sedimentation rate, anemia, and serum albumin. In advanced disease the number of involved nodal and extranodal regions, the total tumor burden, B symptoms, age, gender, histology, and a number of hematologic and biochemical indicators are significant. Research...

  16. Process-model simulations of cloud albedo enhancement by aerosols in the Arctic (United States)

    Kravitz, Ben; Wang, Hailong; Rasch, Philip J.; Morrison, Hugh; Solomon, Amy B.


    A cloud-resolving model is used to simulate the effectiveness of Arctic marine cloud brightening via injection of cloud condensation nuclei (CCN), either through geoengineering or other increased sources of Arctic aerosols. An updated cloud microphysical scheme is employed, with prognostic CCN and cloud particle numbers in both liquid and mixed-phase marine low clouds. Injection of CCN into the marine boundary layer can delay the collapse of the boundary layer and increase low-cloud albedo. Albedo increases are stronger for pure liquid clouds than mixed-phase clouds. Liquid precipitation can be suppressed by CCN injection, whereas ice precipitation (snow) is affected less; thus, the effectiveness of brightening mixed-phase clouds is lower than for liquid-only clouds. CCN injection into a clean regime results in a greater albedo increase than injection into a polluted regime, consistent with current knowledge about aerosol–cloud interactions. Unlike previous studies investigating warm clouds, dynamical changes in circulation owing to precipitation changes are small. According to these results, which are dependent upon the representation of ice nucleation processes in the employed microphysical scheme, Arctic geoengineering is unlikely to be effective as the sole means of altering the global radiation budget but could have substantial local radiative effects. PMID:25404677

  17. Process-model simulations of cloud albedo enhancement by aerosols in the Arctic. (United States)

    Kravitz, Ben; Wang, Hailong; Rasch, Philip J; Morrison, Hugh; Solomon, Amy B


    A cloud-resolving model is used to simulate the effectiveness of Arctic marine cloud brightening via injection of cloud condensation nuclei (CCN), either through geoengineering or other increased sources of Arctic aerosols. An updated cloud microphysical scheme is employed, with prognostic CCN and cloud particle numbers in both liquid and mixed-phase marine low clouds. Injection of CCN into the marine boundary layer can delay the collapse of the boundary layer and increase low-cloud albedo. Albedo increases are stronger for pure liquid clouds than mixed-phase clouds. Liquid precipitation can be suppressed by CCN injection, whereas ice precipitation (snow) is affected less; thus, the effectiveness of brightening mixed-phase clouds is lower than for liquid-only clouds. CCN injection into a clean regime results in a greater albedo increase than injection into a polluted regime, consistent with current knowledge about aerosol-cloud interactions. Unlike previous studies investigating warm clouds, dynamical changes in circulation owing to precipitation changes are small. According to these results, which are dependent upon the representation of ice nucleation processes in the employed microphysical scheme, Arctic geoengineering is unlikely to be effective as the sole means of altering the global radiation budget but could have substantial local radiative effects. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  18. Recent Arctic amplification and extreme mid-latitude weather

    NARCIS (Netherlands)

    Cohen, Judah; Screen, James A.; Furtado, Jason C.; Barlow, Mathew; Whittleston, David; Coumou, Dim; Francis, Jennifer; Dethloff, Klaus; Entekhabi, Dara; Overland, James; Jones, Justin


    The Arctic region has warmed more than twice as fast as the global average-a phenomenon known as Arctic amplification. The rapid Arctic warming has contributed to dramatic melting of Arctic sea ice and spring snow cover, at a pace greater than that simulated by climate models. These profound changes


    Directory of Open Access Journals (Sweden)

    A. I. Morozov


    Full Text Available Article is devoted to research of geopolitical position of the Arctic region, its role in modern policy. Approaches of the Arctic countries and of the external regional states to realization of policy in the Arctic are considered. Geopolitical rivalry in the Arctic region is analyzed.

  20. Tipping elements in the Arctic marine ecosystem. (United States)

    Duarte, Carlos M; Agustí, Susana; Wassmann, Paul; Arrieta, Jesús M; Alcaraz, Miquel; Coello, Alexandra; Marbà, Núria; Hendriks, Iris E; Holding, Johnna; García-Zarandona, Iñigo; Kritzberg, Emma; Vaqué, Dolors


    The Arctic marine ecosystem contains multiple elements that present alternative states. The most obvious of which is an Arctic Ocean largely covered by an ice sheet in summer versus one largely devoid of such cover. Ecosystems under pressure typically shift between such alternative states in an abrupt, rather than smooth manner, with the level of forcing required for shifting this status termed threshold or tipping point. Loss of Arctic ice due to anthropogenic climate change is accelerating, with the extent of Arctic sea ice displaying increased variance at present, a leading indicator of the proximity of a possible tipping point. Reduced ice extent is expected, in turn, to trigger a number of additional tipping elements, physical, chemical, and biological, in motion, with potentially large impacts on the Arctic marine ecosystem.

  1. Elemental composition of arctic particulate matter (United States)

    Cahill, T. A.; Eldred, R. A.


    Measurements were made of the elemental composition of particulate matter collected in flights in the Arctic in spring 1983 as part of the Arctic Gas and Aerosol Sampling Program (AGASP). Ten samples of size-selected particles were analyzed by four nondestructive techniques at Davis. Concentrations were determined for H, C, N, and O by Forward Alpha Scattering Techniques (FAST) and for elements heavier than fluorine by Particle Induced X-ray Emission (PIXE). Total mass was measured gravimetrically, and optical absorption was measured using the Laser Integrating Plate Method (LIPM). Results of the analyses show dramatic differences in concentrations and elemental ratios from the Alaskan Arctic to the Norwegian Arctic, with indications of wood smoke and sulfuric acid in the arctic atmosphere.

  2. Arctic ecosystem responses to a warming climate

    DEFF Research Database (Denmark)

    Mortensen, Lars O.

    The Arctic embraces one of the simplest terrestrial ecosystems in the world and yet it covers roughly 11% of the world’s surface. Summer temperatures rarely exceed 10°C and most of the limited precipitation falls as snow. The landmasses are predominantly polar tundra, while the Arctic Ocean...... is frozen solid for the main part of the year. However, in recent decades, arctic temperatures have in-creased between two and three times that of the global averages, which have had a substantial impact on the physical environment of the arctic ecosystem, such as deglaciation of the Greenland inland ice......-trophic interaction patterns. However, while studies have documented the climatic effects on the arctic biotic ecosys-tem, detailed studies have been constrained by short time series or the lack of comprehensive multivariate tools, which enables the disentanglement of direct effects and effects mediated through...

  3. LABEX L-IPSL Arctic Metadata Portal

    Directory of Open Access Journals (Sweden)

    Laura Cordero-Llana


    Full Text Available The Institut Pierre Simon Laplace (IPSL encompasses a wide diversity of projects that focus on the Arctic. From these observations the IPSL has generated a large number of datasets gathering Arctic observations. These observations include measurements on atmospheric chemical composition, snow micro-physical properties or ocean measurements. However, some of these datasets remain locally stored and there is a lack of public awareness regarding these resources, which has hindered their visualisation and sharing. This motivated the creation of the LABEX L-IPSL Arctic metadata Portal (, presented here, which improves the visibility of the variety of observations collected within the institute as well as the evaluation of numerical models. The LABEX L-IPSL Arctic metadata Portal will also promote new avenues in Arctic research within the IPSL and with other collaborating institutions.


    Directory of Open Access Journals (Sweden)

    Vanja Lež


    Full Text Available The existence of large quantities of hydrocarbons is supposed within the Arctic Circle. Assumed quantities are 25% of the total undiscovered hydrocarbon reserves on Earth, mostly natural gas. Over 500 major and minor gas accumulations within the Arctic Circle were discovered so far, but apart from Snøhvit gas field, there is no commercial exploitation of natural gas from these fields. Arctic gas projects are complicated, technically hard to accomplish, and pose a great threat to the return of investment, safety of people and equipment and for the ecosystem. Russia is a country that is closest to the realization of the Arctic gas projects that are based on the giant gas fields. The most extreme weather conditions in the seas around Greenland are the reason why this Arctic region is the least explored and furthest from the realization of any gas project (the paper is published in Croatian .

  5. Timber logging in central Siberia is the main source for recent Arctic driftwood

    Czech Academy of Sciences Publication Activity Database

    Hellmann, L.; Tegel, W.; Kirdyanov, A. V.; Eggertsson, O.; Esper, J.; Agafonov, L.; Nikolaev, A. N.; Knorre, A. A.; Myglan, V. S.; Churakova (Sidorova), O.; Schweingruber, F. H.; Nievergelt, D.; Verstege, A.; Büntgen, Ulf


    Roč. 47, č. 3 (2015), s. 449-460 ISSN 1523-0430 R&D Projects: GA MŠk(CZ) EE2.3.20.0248 Institutional support: RVO:67179843 Keywords : mackenzie river driftwood * tree-ring width * sea-ice * ocean * origin * water * holocene * impact * north * chronology Subject RIV: EH - Ecology, Behaviour Impact factor: 1.455, year: 2015

  6. Advancing NOAA NWS Arctic Program Development (United States)

    Timofeyeva-Livezey, M. M.; Horsfall, F. M. C.; Meyers, J. C.; Churma, M.; Thoman, R.


    Environmental changes in the Arctic require changes in the way the National Oceanic and Atmospheric Administration (NOAA) delivers hydrological and meteorological information to prepare the region's societies and indigenous population for emerging challenges. These challenges include changing weather patterns, changes in the timing and extent of sea ice, accelerated soil erosion due to permafrost decline, increasing coastal vulnerably, and changes in the traditional food supply. The decline in Arctic sea ice is opening new opportunities for exploitation of natural resources, commerce, tourism, and military interest. These societal challenges and economic opportunities call for a NOAA integrated approach for delivery of environmental information including climate, water, and weather data, forecasts, and warnings. Presently the NOAA Arctic Task Force provides leadership in programmatic coordination across NOAA line offices. National Weather Service (NWS) Alaska Region and the National Centers for Environmental Prediction (NCEP) provide the foundational operational hydro-meteorological products and services in the Arctic. Starting in 2016, NOAA's NWS will work toward improving its role in programmatic coordination and development through assembling an NWS Arctic Task Team. The team will foster ties in the Arctic between the 11 NWS national service programs in climate, water, and weather information, as well as between Arctic programs in NWS and other NOAA line offices and external partners. One of the team outcomes is improving decision support tools for the Arctic. The Local Climate Analysis Tool (LCAT) currently has more than 1100 registered users, including NOAA staff and technical partners. The tool has been available online since 2013 ( ). The tool links trusted, recommended NOAA data and analytical capabilities to assess impacts of climate variability and climate change at local levels. A new capability currently being developed will

  7. The Arctic zone: possibilities and risks of development (United States)

    Sentsov, A.; Bolsunovskaya, Y.; Melnikovich, E.


    The authors analyze the Arctic region innovative possibilities from the perspective of political ideology and strategy. The Arctic region with its natural resources and high economic potential attracts many companies and it has become an important area of transnational development. At present, the Arctic region development is of great importance in terms of natural resource management and political system development. However, the most important development issue in the Arctic is a great risk of different countries’ competing interests in economic, political, and legal context. These are challenges for international partnership creating in the Arctic zone, Russian future model developing for the Arctic, and recognition of the Arctic as an important resource for the Russians. The Russian economic, military, and political expansion in the Arctic region has the potential to strengthen the national positions. The authors present interesting options for minimizing and eliminating political risks during the Arctic territories development and define an effective future planning model for the Russian Arctic.

  8. Prognostic radiographic aspects of spondylolisthesis

    Energy Technology Data Exchange (ETDEWEB)

    Saraste, H.; Brostroem, L.A.; Aparisi, T.


    A series of 202 patients (133 men, 69 women) with lumbar spondylolysis were examined radiographically on two occasions, first at the time of diagnosis and later at a follow-up, after an observation period of 20 years or more. The films from patients in groups without and with moderate and severe olisthesis were evaluated with respect to variables describing lumbosacral lordosis, wedging of the spondylolytic vertebra, lengths of the transverse processes and iliolumbar ligaments, disk height, progression of slipping, and influence on measured olisthesis of lumbar spine flexion and extension at the radiographic examination. The evaluation was made with special attention to possible signs which could be predictive for the prognosis of vertebral slipping. Progression of slipping did not differ between patients diagnosed as adults or adolescents. Reduction of disk height was correlated to the degree of slipping present at the initial examination and to the progression of olisthesis. Flexion and extension of the lumbar spine did not modify the degree of olisthesis. Data concerning the lengths of the transverse processes and the iliolumbar ligaments, and lumbar lordosis, cannot be used for prognostic purposes. The lumbar index reflecting the degree of wedge deformity of the spondylolytic vertebra was shown to be the only variable of prognostic value for the development of vertebral slipping.

  9. Aggressive fibromatosis - impact of prognostic variables on ...

    African Journals Online (AJOL)

    South African Journal of Surgery ... To determine the impact of prognostic variables on local control in patients with aggressive fibromatosis treated with or without radiation. Materials and methods. ... The addition of radiation therapy to surgery as well as other known prognostic parameters did not impact on local control.

  10. Multinational Experiment 7. Maritime Security Region: The Arctic (United States)


    Health · Circumpolar Universities Association Global Regimes Relevant to the Arctic · Law of the Sea: Convention on the Law of the Sea · Ozone Layer ...inevitable about deterioration of relations in the Arctic even though cooperation is the preferred modus operandi at the moment. Because the Arctic...make this understood by pursuing policies in the Arctic that could lead to deteriorating relationships among the Arctic states. A final point here is

  11. Arctic Visiting Speakers Series (AVS) (United States)

    Fox, S. E.; Griswold, J.


    The Arctic Visiting Speakers (AVS) Series funds researchers and other arctic experts to travel and share their knowledge in communities where they might not otherwise connect. Speakers cover a wide range of arctic research topics and can address a variety of audiences including K-12 students, graduate and undergraduate students, and the general public. Host applications are accepted on an on-going basis, depending on funding availability. Applications need to be submitted at least 1 month prior to the expected tour dates. Interested hosts can choose speakers from an online Speakers Bureau or invite a speaker of their choice. Preference is given to individuals and organizations to host speakers that reach a broad audience and the general public. AVS tours are encouraged to span several days, allowing ample time for interactions with faculty, students, local media, and community members. Applications for both domestic and international visits will be considered. Applications for international visits should involve participation of more than one host organization and must include either a US-based speaker or a US-based organization. This is a small but important program that educates the public about Arctic issues. There have been 27 tours since 2007 that have impacted communities across the globe including: Gatineau, Quebec Canada; St. Petersburg, Russia; Piscataway, New Jersey; Cordova, Alaska; Nuuk, Greenland; Elizabethtown, Pennsylvania; Oslo, Norway; Inari, Finland; Borgarnes, Iceland; San Francisco, California and Wolcott, Vermont to name a few. Tours have included lectures to K-12 schools, college and university students, tribal organizations, Boy Scout troops, science center and museum patrons, and the general public. There are approximately 300 attendees enjoying each AVS tour, roughly 4100 people have been reached since 2007. The expectations for each tour are extremely manageable. Hosts must submit a schedule of events and a tour summary to be posted online

  12. Concordance for prognostic models with competing risks

    DEFF Research Database (Denmark)

    Wolbers, Marcel; Blanche, Paul; Koller, Michael T


    The concordance probability is a widely used measure to assess discrimination of prognostic models with binary and survival endpoints. We formally define the concordance probability for a prognostic model of the absolute risk of an event of interest in the presence of competing risks and relate i...... of the working model. We further illustrate the methods by computing the concordance probability for a prognostic model of coronary heart disease (CHD) events in the presence of the competing risk of non-CHD death.......The concordance probability is a widely used measure to assess discrimination of prognostic models with binary and survival endpoints. We formally define the concordance probability for a prognostic model of the absolute risk of an event of interest in the presence of competing risks and relate...

  13. Model-Based Prognostics of Hybrid Systems (United States)

    Daigle, Matthew; Roychoudhury, Indranil; Bregon, Anibal


    Model-based prognostics has become a popular approach to solving the prognostics problem. However, almost all work has focused on prognostics of systems with continuous dynamics. In this paper, we extend the model-based prognostics framework to hybrid systems models that combine both continuous and discrete dynamics. In general, most systems are hybrid in nature, including those that combine physical processes with software. We generalize the model-based prognostics formulation to hybrid systems, and describe the challenges involved. We present a general approach for modeling hybrid systems, and overview methods for solving estimation and prediction in hybrid systems. As a case study, we consider the problem of conflict (i.e., loss of separation) prediction in the National Airspace System, in which the aircraft models are hybrid dynamical systems.

  14. Prognostic molecular markers in cancer - quo vadis? (United States)

    Søland, Tine M; Brusevold, Ingvild J


    Despite the tremendous number of studies of prognostic molecular markers in cancer, only a few such markers have entered clinical practise. The lack of clinical prognostic markers clearly reflects limitations in or an inappropriate approach to prognostic studies. This situation should be of great concern for the research community, clinicians and patients. In the present review, we evaluate immunohistochemical prognostic marker studies in oral squamous cell carcinomas (OSCC) from 2006 to 2012. We comment upon general issues such as study design, assay methods and statistical methods, applicable to prognostic marker studies irrespective of cancer type. The three most frequently studied markers in OSCC are reviewed. Our analysis revealed that most new molecular markers are reported only once. To draw conclusions of clinical relevance based on the few markers that appeared in more than one study was problematic due to between-study heterogeneity. Currently, much valuable tissue material, time and money are wasted on irrelevant studies. © 2013 John Wiley & Sons Ltd.

  15. Arctic Energy Resources: Security and Environmental Implications

    Directory of Open Access Journals (Sweden)

    Peter Johnston


    Full Text Available n recent years, there has been considerable interest in the Arctic as a source for resources, as a potential zone for commercial shipping, and as a region that might experience conflict due to its strategic importance. With regards to energy resources, some studies suggest that the region contains upwards of 13 percent of global undiscovered oil, 30 percent of undiscovered gas, and multiples more of gas hydrates. The decreasing amount and duration of Arctic ice cover suggests that extraction of these resources will be increasingly commercially viable. Arctic and non-arctic states wish to benefit from the region's resources and the potential circum-polar navigation possibilities. This has led to concerns about the environmental risks of these operations as well as the fear that competition between states for resources might result in conflict. Unresolved offshore boundaries between the Arctic states exacerbate these fears. Yet, the risk of conflict seems overstated considering the bilateral and multilateral steps undertaken by the Arctic states to resolve contentious issues. This article will examine the potential impact of Arctic energy resources on global security as well as the regional environment and examine the actions of concerned states to promote their interests in the region.


    Directory of Open Access Journals (Sweden)

    Yury Mazurov


    Full Text Available In September 2010, Moscow hosted the International Arctic Forum “The Arctic—Territory of Dialogue.” The Arctic Forum focused its attention on elements of sustainable development in the Arctic region, i.e., ecology, economics, infrastructure, social services, security, and geopolitics. Many Russian experts and many well-known politicians and experts from leading research centers of the Arctic countries (Canada, Denmark, Finland, Iceland, Norway, Sweden, and USA, as well as by participants from France, Germany, Netherlands, and other countries attended the forum. Scholars and public figures from the European countries, representatives of the NATO, the Organization for Security and Cooperation in Europe and other institutions were also present at the conference. In his key-note speech the Chairman of the Board of Trustees of the Russian Geographical Society (RGS, Prime Minister of the Russian Federation, Vladimir V. Putin formulated the principles of Russian national policy in the Arctic. Russian and foreign participants supported the idea of continuing dialogue on the Arctic under the RGS’s aegis and the transformation of the Arctic Forum into a permanent platform for discussions on the most urgent issues of the region.

  17. Modelling atmospheric structure, cloud and their response to CCN in the central Arctic: ASCOS case studies

    Directory of Open Access Journals (Sweden)

    C. E. Birch


    Full Text Available Observations made during late summer in the central Arctic Ocean, as part of the Arctic Summer Cloud Ocean Study (ASCOS, are used to evaluate cloud and vertical temperature structure in the Met Office Unified Model (MetUM. The observation period can be split into 5 regimes; the first two regimes had a large number of frontal systems, which were associated with deep cloud. During the remainder of the campaign a layer of low-level cloud occurred, typical of central Arctic summer conditions, along with two periods of greatly reduced cloud cover. The short-range operational NWP forecasts could not accurately reproduce the observed variations in near-surface temperature. A major source of this error was found to be the temperature-dependant surface albedo parameterisation scheme. The model reproduced the low-level cloud layer, though it was too thin, too shallow, and in a boundary-layer that was too frequently well-mixed. The model was also unable to reproduce the observed periods of reduced cloud cover, which were associated with very low cloud condensation nuclei (CCN concentrations (<1 cm−3. As with most global NWP models, the MetUM does not have a prognostic aerosol/cloud scheme but uses a constant CCN concentration of 100 cm−3 over all marine environments. It is therefore unable to represent the low CCN number concentrations and the rapid variations in concentration frequently observed in the central Arctic during late summer. Experiments with a single-column model configuration of the MetUM show that reducing model CCN number concentrations to observed values reduces the amount of cloud, increases the near-surface stability, and improves the representation of both the surface radiation fluxes and the surface temperature. The model is shown to be sensitive to CCN only when number concentrations are less than 10–20 cm−3.

  18. Survival strategies in arctic ungulates

    Directory of Open Access Journals (Sweden)

    N. J. C. Tyler


    Full Text Available Arctic ungulates usually neither freeze nor starve to death despite the rigours of winter. Physiological adaptations enable them to survive and reproduce despite long periods of intense cold and potential undernutrition. Heat conservation is achieved by excellent insulation combined with nasal heat exchange. Seasonal variation in fasting metabolic rate has been reported in several temperate and sub-arctic species of ungulates and seems to occur in muskoxen. Surprisingly, there is no evidence for this in reindeer. Both reindeer and caribou normally maintain low levels of locomotor activity in winter. Light foot loads are important for reducing energy expenditure while walking over snow. The significance and control of selective cooling of the brain during hard exercise (e.g. escape from predators is discussed. Like other cervids, reindeer and caribou display a pronounced seasonal cycle of appetite and growth which seems to have an intrinsic basis. This has two consequences. First, the animals evidently survive perfectly well despite enduring negative energy balance for long periods. Second, loss of weight in winter is not necessarily evidence of undernutrition. The main role of fat reserves, especially in males, may be to enhance reproductive success. The principal role of fat reserves in winter appears to be to provide a supplement to, rather than a substitute for, poor quality winter forage. Fat also provides an insurance against death during periods of acute starvation.

  19. The 2008 Circum-Arctic Resource Appraisal (United States)

    Moore, Thomas E.; Gautier, Donald L.


    Professional Paper 1824 comprises 30 chapters by various U.S. Geological Survey authors, including introduction and methodology chapters, which together provide documentation of the geological basis and methodology of the 2008 Circum-Arctic Resource Appraisal, results of which were first released in August 2008.  Twenty-eight chapters summarize the petroleum geology and resource potential of individual, geologically defined provinces north of the Arctic Circle, including those of northern Alaska, northern Canada, east and west Greenland, and most of Arctic Russia, as well as certain offshore areas of the north Atlantic Basin and the Polar Sea. Appendixes tabulate the input and output information used during the assessment.

  20. U.S. Navy Arctic Roadmap Update (United States)


    6 weeks open 41’ controlling draft Transpolar Route 2025: 2 weeks open Deep ocean transit Northwest Passage 2025: intermittently open 33...opera7onal  “model”   14     §  Improved Sea Ice & Weather Forecasts §  High-Resolution Arctic System Models §  Coupled ocean /wave/ice...1   6th Symposium on the Impacts of an Ice-Diminishing Arctic on Naval and Maritime Operations U.S. Navy Arctic Roadmap Update

  1. Physicians' perceptions of the value of prognostic models: the benefits and risks of prognostic confidence. (United States)

    Hallen, Sarah A M; Hootsmans, Norbert A M; Blaisdell, Laura; Gutheil, Caitlin M; Han, Paul K J


    The communication of prognosis in end-of-life (EOL) care is a challenging task that is limited by prognostic uncertainty and physicians' lack of confidence in their prognostic estimates. Clinical prediction models (CPMs) are increasingly common evidence-based tools that may mitigate these problems and facilitate the communication and use of prognostic information in EOL care; however, little is known about physicians' perceptions of the value of these tools. To explore physicians' perceptions of the value of CPMs in EOL care. Qualitative study using semi-structured individual interviews which were analysed using a constant comparative method. Convenience sample of 17 attending physicians representing five different medical specialties at a single large tertiary care medical centre. Physicians perceived CPMs as having three main benefits in EOL care: (i) enhancing their prognostic confidence; (ii) increasing their prognostic authority; and (iii) enabling patient persuasion in circumstances of low prognostic and therapeutic uncertainty. However, physicians also perceived CPMs as having potential risks, which include producing emotional distress in patients and promoting prognostic overconfidence in EOL care. Physicians perceive CPMs as a potentially valuable means of increasing their prognostic confidence, communication and explicit use of prognostic information in EOL care. However, physicians' perceptions of CPMs also indicate a need to establish broad and consistent implementation processes to engage patients in shared decision making in EOL care, to effectively communicate uncertainty in prognostic information and to help both patients and physicians manage uncertainty in EOL care decisions. © 2014 John Wiley & Sons Ltd.

  2. Comparison of Myelodysplastic Syndrome Prognostic Scoring Systems (United States)

    Bektaş, Özlen; Üner, Ayşegül; Eliaçık, Eylem; Uz, Burak; Işık, Ayşe; Etgül, Sezgin; Bozkurt, Süreyya; Haznedaroğlu, İbrahim Celalettin; Göker, Hakan; Sayınalp, Nilgün; Aksu, Salih; Demiroğlu, Haluk; Özcebe, Osman İlhami; Büyükaşık, Yahya


    Objective: Myelodysplastic syndrome (MDS) is a clonal hematopoietic stem cell disease. Patients are at risk of developing cytopenias or progression to acute myeloid leukemia. Different classifications and prognostic scoring systems have been developed. The aim of this study was to compare the different prognostic scoring systems. Materials and Methods: One hundred and one patients who were diagnosed with primary MDS in 2003-2011 in a tertiary care university hospital’s hematology department were included in the study. Results: As the International Prognostic Scoring System (IPSS), World Health Organization Classification-Based Prognostic Scoring System (WPSS), MD Anderson Prognostic Scoring System (MPSS), and revised IPSS (IPSS-R) risk categories increased, leukemia-free survival and overall survival decreased (p<0.001). When the IPSS, WPSS, MPSS, and IPSS-R prognostic systems were compared by Cox regression analysis, the WPSS was the best in predicting leukemia-free survival (p<0.001), and the WPSS (p<0.001) and IPSS-R (p=0.037) were better in predicting overall survival. Conclusion: All 4 prognostic systems were successful in predicting overall survival and leukemia-free survival (p<0.001). The WPSS was found to be the best predictor for leukemia-free survival, while the WPSS and IPSS-R were found to be the best predictors for overall survival. PMID:26376664

  3. Comparison of Myelodysplastic Syndrome Prognostic Scoring Systems

    Directory of Open Access Journals (Sweden)

    Özlen Bektaş


    Full Text Available Objective: Myelodysplastic syndrome (MDS is a clonal hematopoietic stem cell disease. Patients are at risk of developing cytopenias or progression to acute myeloid leukemia. Different classifications and prognostic scoring systems have been developed. The aim of this study was to compare the different prognostic scoring systems. Materials and Methods: One hundred and one patients who were diagnosed with primary MDS in 2003-2011 in a tertiary care university hospital’s hematology department were included in the study. Results: As the International Prognostic Scoring System (IPSS, World Health Organization Classification-Based Prognostic Scoring System (WPSS, MD Anderson Prognostic Scoring System (MPSS, and revised IPSS (IPSS-R risk categories increased, leukemia-free survival and overall survival decreased (p<0.001. When the IPSS, WPSS, MPSS, and IPSS-R prognostic systems were compared by Cox regression analysis, the WPSS was the best in predicting leukemia-free survival (p<0.001, and the WPSS (p<0.001 and IPSS-R (p=0.037 were better in predicting overall survival. Conclusion: All 4 prognostic systems were successful in predicting overall survival and leukemia-free survival (p<0.001. The WPSS was found to be the best predictor for leukemia-free survival, while the WPSS and IPSS-R were found to be the best predictors for overall survival.

  4. Arctic tipping points in an Earth system perspective. (United States)

    Wassmann, Paul; Lenton, Timothy M


    We provide an introduction to the volume The Arctic in the Earth System perspective: the role of tipping points. The terms tipping point and tipping element are described and their role in current science, general debates, and the Arctic are elucidated. From a wider perspective, the volume focuses upon the role of humans in the Arctic component of the Earth system and in particular the envelope for human existence, the Arctic ecosystems. The Arctic climate tipping elements, the tipping elements in Arctic ecosystems and societies, and the challenges of governance and anticipation are illuminated through short summaries of eight publications that derive from the Arctic Frontiers conference in 2011 and the EU FP7 project Arctic Tipping Points. Then some ideas based upon resilience thinking are developed to show how wise system management could ease pressures on Arctic systems in order to keep them away from tipping points.

  5. Tidal dissipation in the ice-ocean system on Enceladus (United States)

    Hellard, H.; Sohl, F.; Van der Wal, W.; Steinke, T.; Hußmann, H.


    We investigate how the interior structure and dissipation of tidal energy on Enceladus affect the lateral layering of its outer ice shell. Structural models are created that satisfy the satellite's mean density and polar moment-of-inertia factor as derived from Cassini gravity field data. We particularly consider variations in core density, ice shell thickness and ocean composition. A partly dehydrated core is found to be consistent with current ice shell thickness estimates and power output measurements for Enceladus.

  6. Arctic Cold Weather Medicine and Accidental Hypothermia (United States)


    chocolate ) worscn dchydration from increasing urination and should be limited. Adequate drinking must be implemented into the daily routine. With...complications and standard treatments. The rare problems encountered in the Arctic are Salmonella , Typhoid fever, Paratyphoid fever, Shigella (Bacillary

  7. Arctic/North Pacific Ocean Environmental Studies

    National Research Council Canada - National Science Library

    Mikhalevsky, Peter


    .... The objective of the effort was to test the feasibility of acoustic monitoring of the Arctic Ocean and ice cap using long range low frequency acoustic propagation, by answering the fundamental questions: (1...

  8. Arctic Ocean Regional Climatology (NCEI Accession 0115771) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To provide an improved oceanographic foundation and reference for multi-disciplinary studies of the Arctic Ocean, NCEI developed a new set of high-resolution...

  9. Arctic parasitology: why should we care? (United States)

    Davidson, Rebecca; Simard, Manon; Kutz, Susan J; Kapel, Christian M O; Hamnes, Inger S; Robertson, Lucy J


    The significant impact on human and animal health from parasitic infections in tropical regions is well known, but parasites of medical and veterinary importance are also found in the Arctic. Subsistence hunting and inadequate food inspection can expose people of the Arctic to foodborne parasites. Parasitic infections can influence the health of wildlife populations and thereby food security. The low ecological diversity that characterizes the Arctic imparts vulnerability. In addition, parasitic invasions and altered transmission of endemic parasites are evident and anticipated to continue under current climate changes, manifesting as pathogen range expansion, host switching, and/or disease emergence or reduction. However, Arctic ecosystems can provide useful models for understanding climate-induced shifts in host-parasite ecology in other regions.

  10. Arctic Landfast Sea Ice 1953-1998 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The files in this data set contain landfast sea ice data (monthly means) gathered from both Russian Arctic and Antarctic Research Institute (AARI) and Canadian Ice...

  11. Geologic Provinces of the Arctic, 2000 (prvarcst) (United States)

    U.S. Geological Survey, Department of the Interior — This coverage includes arcs, polygons and polygon labels that describe Arctic portion of the U.S. Geological Survey defined geologic provinces of the World in 2000.

  12. Methane from the East Siberian Arctic shelf

    DEFF Research Database (Denmark)

    Petrenko...[], Vasilii V.; Etheridge, David M.


    In their Report “Extensive methane venting to the atmosphere from sediments of the East Siberian Arctic Shelf” (5 March, p. 1246), N. Shakhova et al. write that methane (CH4) release resulting from thawing Arctic permafrost “is a likely positive feedback to climate warming.” They add...... that the release of Arctic CH4 was implied in previous climate shifts as well as in the recently renewed rise in atmospheric CH4. These claims are not supported by all the literature they cite. Their reference 5 (1) presents measurements of emissions only of carbon dioxide, not CH4. Their reference 8 (2), a study...... the Report and in (6)] add to our understanding of the atmospheric CH4 budget, but they do not show that Arctic warming has produced a positive feedback in radiative forcing by causing these emissions to increase recently. A newly discovered CH4 source is not necessarily a changing source, much less a source...

  13. Methan Dynamics in an Arctic Wetland

    DEFF Research Database (Denmark)

    Nielsen, Cecilie Skov

    Rising temperatures in the Arctic have the potential to increase methane (CH4) emissions from arctic wetlands due to increased decomposition, changes in vegetation cover, and increased substrate input from vegetation and thawing permafrost. The effects of warming and changes in vegetation cover...... be used to oxidize CH4. The over all effect of the presence of sedges on the CH4 budget is unknown for most arctic species. Here the effects of warming and changes in plant cover on CH4 dynamics and emissions in a wetland in Blæsedalen, Disko Island, W. Greenland were investigated. The importance of CH4...... on CH4 emissions are however still largely unknown for the Arctic. Many wetlands plants such as sedges can increase CH4 emissions by transporting the CH4 through internal air tissue. However, at the same time the plants can reduce the CH4 emissions by transporting oxygen to the rhizosphere where it can...

  14. Historical Arctic and Antarctic Surface Observational Data (United States)

    National Aeronautics and Space Administration — This product consists of meteorological data from 105 Arctic weather stations and 137 Antarctic stations, extracted from the National Climatic Data Center (NCDC)'s...

  15. Arctic National Wildlife Range, Annual Narrative Report (United States)

    US Fish and Wildlife Service, Department of the Interior — The Arctic National Wildlife Range (ANWR) was established by executive order in 1960 for the purpose of preserving unique wildlife, wilderness and recreational...

  16. Arctic and Southern Ocean Sea Ice Concentrations (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly sea ice concentration for Arctic (1901 to 1995) and Southern oceans (1973 to 1990) were digitized on a standard 1-degree grid (cylindrical projection) to...

  17. Centennial Valley Arctic Grayling Adaptive Management Plan (United States)

    US Fish and Wildlife Service, Department of the Interior — Montana Arctic grayling (grayling) were patchily distributed throughout the Upper Missouri River (UMR) drainage prior to the mid-1850's. This population declined to...

  18. Arctic and Aleutian terns, Amchitka Island, Alaska (United States)

    US Fish and Wildlife Service, Department of the Interior — Baird (1980) has recently reported on the ecology of Arctic terns (Sterna paradisaea) and Aleutian terns (Sterna aleutica) from 4 areas of mainland Alaska. However,...

  19. Acoustic Resonance Reaction Control Thruster (ARCTIC) Project (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop and demonstrate the innovative Acoustic Resonance Reaction Control Thruster (ARCTIC) to provide rapid and reliable in-space impulse...

  20. NCEP/NCAR Arctic Marine Rawinsonde Archive (United States)

    National Aeronautics and Space Administration — NCEP/NCAR Arctic Marine Rawinsonde Archive, available via ftp, contains 17,659 marine rawinsonde reports for the region north of 65 degrees North. Its record extends...

  1. Arctic Water Vapor Characteristics from Rawinsondes (United States)

    National Aeronautics and Space Administration — A gridded climatological monthly-mean data base of Arctic water vapor characteristics has been assembled by combining fixed station data with data from soundings...

  2. Arctic Marine Transportation Program 1979-1986 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The purpose of this program was to collect data relevant to developing year-round transportation capabilities in the Arctic Ocean. The US Maritime Administration...

  3. Arctic Sea Ice Freeboard and Thickness (United States)

    National Aeronautics and Space Administration — This data set provides measurements of sea ice freeboard and sea ice thickness for the Arctic region. The data were derived from measurements made by from the Ice,...

  4. In Brief: Online Arctic mapping feature unveiled (United States)

    Kumar, Mohi


    The Arctic Research Mapping Application (ARMAP), a Web portal of interactive maps and services, can now be used in conjunction with Google Earth. The new feature allows users to readily interface between satellite images, road and political maps, and other baseline information. ARMAP (see supports Arctic science with special emphasis on promoting the current International Polar Year and is funded by the National Science Foundation's Office of Polar Programs.

  5. Coarse mode aerosols in the High Arctic (United States)

    Baibakov, K.; O'Neill, N. T.; Chaubey, J. P.; Saha, A.; Duck, T. J.; Eloranta, E. W.


    Fine mode (submicron) aerosols in the Arctic have received a fair amount of scientific attention in terms of smoke intrusions during the polar summer and Arctic haze pollution during the polar winter. Relatively little is known about coarse mode (supermicron) aerosols, notably dust, volcanic ash and sea salt. Asian dust is a regular springtime event whose optical and radiative forcing effects have been fairly well documented at the lower latitudes over North America but rarely reported for the Arctic. Volcanic ash, whose socio-economic importance has grown dramatically since the fear of its effects on aircraft engines resulted in the virtual shutdown of European civil aviation in the spring of 2010 has rarely been reported in the Arctic in spite of the likely probability that ash from Iceland and the Aleutian Islands makes its way into the Arctic and possibly the high Arctic. Little is known about Arctic sea salt aerosols and we are not aware of any literature on the optical measurement of these aerosols. In this work we present preliminary results of the combined sunphotometry-lidar analysis at two High Arctic stations in North America: PEARL (80°N, 86°W) for 2007-2011 and Barrow (71°N,156°W) for 2011-2014. The multi-years datasets were analyzed to single out potential coarse mode incursions and study their optical characteristics. In particular, CIMEL sunphotometers provided coarse mode optical depths as well as information on particle size and refractive index. Lidar measurements from High Spectral Resolution lidars (AHSRL at PEARL and NSHSRL at Barrow) yielded vertically resolved aerosol profiles and gave an indication of particle shape and size from the depolarization ratio and color ratio profiles. Additionally, we employed supplementary analyses of HYSPLIT backtrajectories, OMI aerosol index, and NAAPS (Navy Aerosol Analysis and Prediction System) outputs to study the spatial context of given events.

  6. Studying ocean acidification in the Arctic Ocean (United States)

    Robbins, Lisa


    The U.S. Geological Survey (USGS) partnership with the U.S. Coast Guard Ice Breaker Healey and its United Nations Convention Law of the Sea (UNCLOS) cruises has produced new synoptic data from samples collected in the Arctic Ocean and insights into the patterns and extent of ocean acidification. This framework of foundational geochemical information will help inform our understanding of potential risks to Arctic resources due to ocean acidification.

  7. Redefining U.S. Arctic Strategy (United States)


    52 Xie, Kevin. Some BRICS in the Arctic: Developing Powers Look North, Harvard International Review, Vol 36, No. 3, Spring 2015. Accessed 11...May 2015 at < 411013832/some- brics -in-the-arctic-developing-powers-look-north> 18 Strategy for the...2013. Vego, Milan. Joint Operational Warfare, Theory and Practice. Newport, RI: U.S. Naval War College, 2009. Xie, Kevin. Some BRICS in the

  8. Understanding Tropospheric Ozone Variability in the Arctic (United States)

    McClure-Begley, A.; Petropavlovskikh, I. V.; Crepinsek, S.; Uttal, T.; Skov, H.


    The Arctic is a region that has been subject to drastic changes in the climate partially due to transported pollutants which strongly impact the composition of the atmosphere and associated feedbacks. Tropospheric ozone is an atmospheric species formed by the reaction of precursor species (NOx, CO, VOC's) in the presence of UV radiation and drives complex interactions which can result in impacts on atmospheric conditions in the Arctic. As an important greenhouse gas, ozone has a significant influence on the photochemical characteristics, oxidation capacity, and radiative forcing of the atmosphere and at high levels has negative impacts on public health and overall ecosystem functioning. In the Arctic, tropospheric ozone has variable characteristics in time and space. Seasonal variation of ozone is controlled by many factors influencing the production and destruction of ozone. The arctic ozone conditions are strongly influenced by seasonal destruction events, arctic haze, transport of pollution from Asia and influence from precursor compounds released from wildfires. This study investigates long-term ozone variation, seasonal surface ozone conditions, and characterizes deviations from expected ozone levels at four arctic ozone measurement locations (Barrow Alaska, Tiksi Russia, Summit Greenland, and Villum Station Greenland). Frequency of ozone depletion events and high ozone episodes for each station over time provides a context for the changing conditions of ozone in the arctic. NOAA Hysplit back-trajectory analysis, satellite imagery, NOAA Smoke verification model, co-located carbon monoxide, carbon dioxide, and aerosol optical depth measurements are used to understand the dominant source of pollution, pollutant composition, and the interactions due to meteorological conditions that result in anomalies in the ozone mixing ratio records. Characterization of ozone behavior and influences on the measurement locations is essential for understanding the spatial and

  9. Zooplankton in the Arctic outflow (United States)

    Soloviev, K. A.; Dritz, A. V.; Nikishina, A. B.


    Climate changes in the Arctic cause the changes in the current system that may have cascading effect on the structure of plankton community and consequently on the interlinked and delicately balanced food web. Zooplankton species are by definition incapable to perform horizontal moving. Their transport is connected with flowing water. There are zooplankton species specific for the definite water masses and they can be used as markers for the different currents. That allows us to consider zooplankton community composition as a result of water mixing in the studied area. Little is known however about the mechanisms by which spatial and temporal variability in advection affect dynamics of local populations. Ice conditions are also very important in the function of pelagic communities. Melting time is the trigger to all "plankton blooming" processes, and the duration of ice-free conditions determines the food web development in the future. Fram Strait is one of the key regions for the Arctic: the cold water outflow comes through it with the East Greenland Current and meets warm Atlantic water, the West Spitsbergen Current, producing complicated hydrological situation. During 2007 and 2008 we investigated the structure functional characteristics of zooplankton community in the Fram Strait region onboard KV "Svalbard" (April 2007, April and May 2008) and RV "Jan Mayen" (May 2007, August 2008). This study was conducted in frame of iAOOS Norway project "Closing the loop", which, in turn, was a part of IPY. During this cruises multidisciplinary investigations were performed, including sea-ice observations, CTD and ADCP profiling, carbon flux, nutrients and primary production measurements, phytoplankton sampling. Zooplankton was collected with the Hydro-Bios WP2 net and MultiNet Zooplankton Sampler, (mouth area 0.25 m2, mesh size 180 um).Samples were taken from the depth strata of 2000-1500, 1500-1000, 1000-500,500-200, 200-100, 100-60, 60-30, 30-0 m. Gut fluorescence

  10. Arctic Ocean data in CARINA

    Directory of Open Access Journals (Sweden)

    S. Jutterström


    Full Text Available The paper describes the steps taken for quality controlling chosen parameters within the Arctic Ocean data included in the CARINA data set and checking for offsets between the individual cruises. The evaluated parameters are the inorganic carbon parameters (total dissolved inorganic carbon, total alkalinity and pH, oxygen and nutrients: nitrate, phosphate and silicate. More parameters can be found in the CARINA data product, but were not subject to a secondary quality control. The main method in determining offsets between cruises was regional multi-linear regression, after a first rough basin-wide deep-water estimate of each parameter. Lastly, the results of the secondary quality control are discussed as well as applied adjustments.

  11. Active molecular iodine photochemistry in the Arctic (United States)

    Raso, Angela R. W.; Custard, Kyle D.; May, Nathaniel W.; Tanner, David; Newburn, Matt K.; Walker, Lawrence; Moore, Ronald J.; Huey, L. G.; Alexander, Liz; Shepson, Paul B.; Pratt, Kerri A.


    During springtime, the Arctic atmospheric boundary layer undergoes frequent rapid depletions in ozone and gaseous elemental mercury due to reactions with halogen atoms, influencing atmospheric composition and pollutant fate. Although bromine chemistry has been shown to initiate ozone depletion events, and it has long been hypothesized that iodine chemistry may contribute, no previous measurements of molecular iodine (I2) have been reported in the Arctic. Iodine chemistry also contributes to atmospheric new particle formation and therefore cloud properties and radiative forcing. Here we present Arctic atmospheric I2 and snowpack iodide (I-) measurements, which were conducted near Utqiaġvik, AK, in February 2014. Using chemical ionization mass spectrometry, I2 was observed in the atmosphere at mole ratios of 0.3-1.0 ppt, and in the snowpack interstitial air at mole ratios up to 22 ppt under natural sunlit conditions and up to 35 ppt when the snowpack surface was artificially irradiated, suggesting a photochemical production mechanism. Further, snow meltwater I- measurements showed enrichments of up to ˜1,900 times above the seawater ratio of I-/Na+, consistent with iodine activation and recycling. Modeling shows that observed I2 levels are able to significantly increase ozone depletion rates, while also producing iodine monoxide (IO) at levels recently observed in the Arctic. These results emphasize the significance of iodine chemistry and the role of snowpack photochemistry in Arctic atmospheric composition, and imply that I2 is likely a dominant source of iodine atoms in the Arctic.

  12. Active molecular iodine photochemistry in the Arctic. (United States)

    Raso, Angela R W; Custard, Kyle D; May, Nathaniel W; Tanner, David; Newburn, Matt K; Walker, Lawrence; Moore, Ronald J; Huey, L G; Alexander, Liz; Shepson, Paul B; Pratt, Kerri A


    During springtime, the Arctic atmospheric boundary layer undergoes frequent rapid depletions in ozone and gaseous elemental mercury due to reactions with halogen atoms, influencing atmospheric composition and pollutant fate. Although bromine chemistry has been shown to initiate ozone depletion events, and it has long been hypothesized that iodine chemistry may contribute, no previous measurements of molecular iodine (I2) have been reported in the Arctic. Iodine chemistry also contributes to atmospheric new particle formation and therefore cloud properties and radiative forcing. Here we present Arctic atmospheric I2 and snowpack iodide (I(-)) measurements, which were conducted near Utqiaġvik, AK, in February 2014. Using chemical ionization mass spectrometry, I2 was observed in the atmosphere at mole ratios of 0.3-1.0 ppt, and in the snowpack interstitial air at mole ratios up to 22 ppt under natural sunlit conditions and up to 35 ppt when the snowpack surface was artificially irradiated, suggesting a photochemical production mechanism. Further, snow meltwater I(-) measurements showed enrichments of up to ∼1,900 times above the seawater ratio of I(-)/Na(+), consistent with iodine activation and recycling. Modeling shows that observed I2 levels are able to significantly increase ozone depletion rates, while also producing iodine monoxide (IO) at levels recently observed in the Arctic. These results emphasize the significance of iodine chemistry and the role of snowpack photochemistry in Arctic atmospheric composition, and imply that I2 is likely a dominant source of iodine atoms in the Arctic.

  13. Tackling V&V for Prognostics (United States)

    National Aeronautics and Space Administration — We believe our approach to gathering and organizing prognostics V the descriptive text recorded proved on occasion to be insufficient to serve as a standalone...

  14. Distilling the Verification Process for Prognostics Algorithms (United States)

    National Aeronautics and Space Administration — The goal of prognostics and health management (PHM) systems is to ensure system safety, and reduce downtime and maintenance costs. It is important that a PHM system...

  15. Prognostic Factors for Refractory Status Epilepticus

    Directory of Open Access Journals (Sweden)

    J. Gordon Millichap


    Full Text Available Researchers at the Mayo Clinic, Rochester, MN studied the outcome and identified prognostic factors for refractory status epilepticus (RSE in 54 adult patients, median age 52 years [range 18-93].

  16. Requirements Flowdown for Prognostics and Health Management (United States)

    National Aeronautics and Space Administration — Prognostics and Health Management (PHM) principles have considerable promise to change the game of lifecycle cost of engineering systems at high safety levels by...

  17. Evaluating Algorithm Performance Metrics Tailored for Prognostics (United States)

    National Aeronautics and Space Administration — Prognostics has taken center stage in Condition Based Maintenance (CBM) where it is desired to estimate Remaining Useful Life (RUL) of a system so that remedial...

  18. Detection and Prognostics on Low Dimensional Systems (United States)

    National Aeronautics and Space Administration — This paper describes the application of known and novel prognostic algorithms on systems that can be described by low dimensional, potentially nonlinear dynamics....

  19. Precursor Parameter Identification for IGBT Prognostics (United States)

    National Aeronautics and Space Administration — Precursor parameters have been identified to enable development of a prognostic approach for insulated gate bipolar transistors (IGBT). The IGBT were subjected to...

  20. Model-based Prognostics under Limited Sensing (United States)

    National Aeronautics and Space Administration — Prognostics is crucial to providing reliable condition-based maintenance decisions. To obtain accurate predictions of component life, a variety of sensors are often...

  1. How to appraise a prognostic study. (United States)

    Mak, Kenneth; Kum, Cheng Kiong


    Prognostic studies are studies that examine selected predictive variables or risk factors and assess their influence on the outcome of a disease. They allow clinicians to understand better the natural history of a disease, guide clinical decision-making by facilitating the selection of appropriate treatment options, and allow more accurate prediction of disease outcomes. Appraising prognostic studies involves determining the internal validity of the study design and evaluating the influence of systemic errors or bias. In studies examining multiple prognostic variables, care must be taken to minimize the confounding influence each variable would have on the other parameters. Evaluating the results of appropriate statistical analysis enables conclusions to be made that may influence clinical practice. Care must be taken to ensure that the conditions under which the prognostic study were conducted resemble circumstances in the local institution so as to allow the conclusions to be applied to local practices.

  2. Myelodysplastic syndrome: classification and prognostic systems

    Directory of Open Access Journals (Sweden)

    Rosangela Invernizzi


    Full Text Available Myelodysplastic syndromes (MDS are acquired clonal disorders of hematopoiesis, that are characterized most frequently by normocellular or hypercellular bone marrow specimens, and maturation that is morphologically and functionally dysplastic. MDS constitute a complex hematological problem: differences in disease presentation, progression and outcome have made it necessary to use classification systems to improve diagnosis, prognostication and treatment selection. On the basis of new scientific and clinical information, classification and prognostic systems have recently been updated and minimal diagnostic criteria forMDS have been proposed by expert panels. In addition, in the last few years our ability to define the prognosis of the individual patient with MDS has improved. In this paper World Health Organization (WHO classification refinements and recent prognostic scoring systems for the definition of individual risk are highlighted and current criteria are discussed. The recommendations should facilitate diagnostic and prognostic evaluations in MDS and selection of patients for new effective targeted therapies.

  3. Metrics for Evaluating Performance of Prognostics Techniques (United States)

    National Aeronautics and Space Administration — Prognostics is an emerging concept in condition based maintenance (CBM) of critical systems. Along with developing the fundamentals of being able to confidently...

  4. Indian Interest in the Arctic in the Context of China’s Arctic Policy

    Directory of Open Access Journals (Sweden)

    Nikolay A. Nikolaev


    Full Text Available The study examines the general and excellent in the Arctic policy of India and China and the likelihood of rivalry between the two Asian powers in the allocation of resources to the Arctic. Also, Indian and Chinese research trends on Arctic topics were considered.Since the middle of XX century. India and China act as long-standing rivals. Periodically, military clashes broke out between the two sides on a common border. Despite the fact that the key territorial issues on the common border between India and China are resolved military provocations from both sides do not stop. The latest incident was the transfer of Indian troops to the Chinese border zone in the province of Sikkim. Both powers of Asia are major consumers of energy resources, they are more or less interested in the situation on the global energy market.In the Arctic there are colossal reserves of various resources. Certain difficulties and limitations with access to resources and their equitable distribution can force these countries to compete with each other. However, the lack of a specific position on Arctic issues or the formulated regional strategy for India and China creates a lot of doubt about their true intentions. The study of research trends, the activity of Indian and Chinese business structures, as well as the arctic activities of India and China, gives approximate answers to this question.The potentials of India and China are very different in the Arctic. China’s strengths are active participation in international scientific research, the availability of a qualified ice-class crew, active investment in energy and infrastructure projects in the Arctic countries, and fairly stable trade relations with most Arctic countries. The weak side of China is its negative image. Residents of many Arctic countries are very wary of the «rise of China» and its growing interest in the Arctic.Strengths of India are a positive image and a representative diaspora in the Arctic

  5. Vehicle Integrated Prognostic Reasoner (VIPR) Metric Report (United States)

    Cornhill, Dennis; Bharadwaj, Raj; Mylaraswamy, Dinkar


    This document outlines a set of metrics for evaluating the diagnostic and prognostic schemes developed for the Vehicle Integrated Prognostic Reasoner (VIPR), a system-level reasoner that encompasses the multiple levels of large, complex systems such as those for aircraft and spacecraft. VIPR health managers are organized hierarchically and operate together to derive diagnostic and prognostic inferences from symptoms and conditions reported by a set of diagnostic and prognostic monitors. For layered reasoners such as VIPR, the overall performance cannot be evaluated by metrics solely directed toward timely detection and accuracy of estimation of the faults in individual components. Among other factors, overall vehicle reasoner performance is governed by the effectiveness of the communication schemes between monitors and reasoners in the architecture, and the ability to propagate and fuse relevant information to make accurate, consistent, and timely predictions at different levels of the reasoner hierarchy. We outline an extended set of diagnostic and prognostics metrics that can be broadly categorized as evaluation measures for diagnostic coverage, prognostic coverage, accuracy of inferences, latency in making inferences, computational cost, and sensitivity to different fault and degradation conditions. We report metrics from Monte Carlo experiments using two variations of an aircraft reference model that supported both flat and hierarchical reasoning.

  6. Does the Arctic Amplification peak this decade? (United States)

    Martin, Torge; Haine, Thomas W. N.


    Temperatures rise faster in the Arctic than on global average, a phenomenon known as Arctic Amplification. While this is well established from observations and model simulations, projections of future climate (here: RCP8.5) with models of the Coupled Model Intercomparison Project phase 5 (CMIP5) also indicate that the Arctic Amplification has a maximum. We show this by means of an Arctic Amplification factor (AAF), which we define as the ratio of Arctic mean to global mean surface air temperature (SAT) anomalies. The SAT anomalies are referenced to the period 1960-1980 and smoothed by a 30-year running mean. For October, the multi-model ensemble-mean AAF reaches a maximum in 2017. The maximum moves however to later years as Arctic winter progresses: for the autumn mean SAT (September to November) the maximum AAF is found in 2028 and for winter (December to February) in 2060. Arctic Amplification is driven, amongst others, by the ice-albedo feedback (IAF) as part of the more general surface albedo feedback (involving clouds, snow cover, vegetation changes) and temperature effects (Planck and lapse-rate feedbacks). We note that sea ice retreat and the associated warming of the summer Arctic Ocean are not only an integral part of the IAF but are also involved in the other drivers. In the CMIP5 simulations, the timing of the AAF maximum coincides with the period of fastest ice retreat for the respective month. Presence of at least some sea ice is crucial for the IAF to be effective because of the contrast in surface albedo between ice and open water and the need to turn ocean warming into ice melt. Once large areas of the Arctic Ocean are ice-free, the IAF should be less effective. We thus hypothesize that the ice retreat significantly affects AAF variability and forces a decline of its magnitude after at least half of the Arctic Ocean is ice-free and the ice cover becomes basically seasonal.

  7. Arctic summer school onboard an icebreaker (United States)

    Alexeev, Vladimir A.; Repina, Irina A.


    The International Arctic Research Center (IARC) of the University of Alaska Fairbanks conducted a summer school for PhD students, post-docs and early career scientists in August-September 2013, jointly with an arctic expedition as a part of NABOS project (Nansen and Amundsen Basin Observational System) onboard the Russian research vessel "Akademik Fedorov". Both the summer school and NABOS expedition were funded by the National Science Foundation. The one-month long summer school brought together graduate students and young scientists with specialists in arctic oceanography and climate to convey to a new generation of scientists the opportunities and challenges of arctic climate observations and modeling. Young scientists gained hands-on experience during the field campaign and learned about key issues in arctic climate from observational, diagnostic, and modeling perspectives. The summer school consisted of background lectures, participation in fieldwork and mini-projects. The mini-projects were performed in collaboration with summer school instructors and members of the expedition. Key topics covered in the lectures included: - arctic climate: key characteristics and processes; - physical processes in the Arctic Ocean; - sea ice and the Arctic Ocean; - trace gases, aerosols, and chemistry: importance for climate changes; - feedbacks in the arctic system (e.g., surface albedo, clouds, water vapor, circulation); - arctic climate variations: past, ongoing, and projected; - global climate models: an overview. An outreach specialist from the Miami Science Museum was writing a blog from the icebreaker with some very impressive statistics (results as of January 1, 2014): Total number of blog posts: 176 Blog posts written/contributed by scientists: 42 Blog views: 22,684 Comments: 1,215 Number of countries who viewed the blog: 89 (on 6 continents) The 33-day long NABOS expedition started on August 22, 2013 from Kirkenes, Norway. The vessel ("Akademik Fedorov") returned to

  8. Prognostic markers of canine pyometra

    Directory of Open Access Journals (Sweden)

    M.C. Sant'Anna


    Full Text Available The pyometra is a disease that affects middle age and elderly female dogs during diestrus. Hormonal, microbiological, biochemical and hematological aspects are well described. However, few studies have evaluated the role of each in the prognosis of canine pyometra. The aim of this study was to identify markers associated with clinical worsening of dogs with pyometra. We prospectively evaluated 80 dogs with pyometra treated surgically. Group 1 consisted of dogs that were discharged within 48 hours after surgery and Group 2 consisted of those who required prolonged hospitalization or died. The findings of hematological, biochemical and blood lactate levels were compared between groups and variables such as bacterial multidrug resistance, systemic inflammatory response syndrome (SIRS, hyperlactatemia and increased creatinine were analyzed through the dispersion of frequencies between groups. Among the variables studied, the presence of SIRS and elevated serum creatinine >2.5mg/mL were effective in predicting the worsening of the disease and can be used as prognostic markers of canine pyometra.

  9. The Arctic Grand Challenge: Abrupt Climate Change (United States)

    Wilkniss, P. E.


    Trouble in polar paradise (Science, 08/30/02), significant changes in the Arctic environment are scientifically documented (R.E. Moritz et al. ibid.). More trouble, lots more, "abrupt climate change," (R. B. Alley, et al. Science 03/28/03). R. Corell, Arctic Climate Impact Assessment team (ACIA), "If you want to see what will happen in the rest of the world 25 years from now just look what's happening in the Arctic," (Arctic Council meeting, Iceland, 08/03). What to do? Make abrupt Arctic climate change a grand challenge for the IPY-4 and beyond! Scientifically:Describe the "state" of the Arctic climate system as succinctly as possible and accept it as the point of departure.Develop a hypothesis and criteria what constitutes "abrupt climate change," in the Arctic that can be tested with observations. Observations: Bring to bear existing observations and coordinate new investments in observations through an IPY-4 scientific management committee. Make the new Barrow, Alaska, Global Climate Change Research Facility a major U.S. contribution and focal point for the IPY-4 in the U.S Arctic. Arctic populations, Native peoples: The people of the North are living already, daily, with wrenching change, encroaching on their habitats and cultures. For them "the earth is faster now," (I. Krupnik and D. Jolly, ARCUS, 2002). From a political, economic, social and entirely realistic perspective, an Arctic grand challenge without the total integration of the Native peoples in this effort cannot succeed. Therefore: Communications must be established, and the respective Native entities must be approached with the determination to create well founded, well functioning, enduring partnerships. In the U.S. Arctic, Barrow with its long history of involvement and active support of science and with the new global climate change research facility should be the focal point of choice Private industry: Resource extraction in the Arctic followed by oil and gas consumption, return the combustion

  10. A quantitative assessment of Arctic shipping in 2010–2014

    KAUST Repository

    Eguíluz, Victor M.


    Rapid loss of sea ice is opening up the Arctic Ocean to shipping, a practice that is forecasted to increase rapidly by 2050 when many models predict that the Arctic Ocean will largely be free of ice toward the end of summer. These forecasts carry considerable uncertainty because Arctic shipping was previously considered too sparse to allow for adequate validation. Here, we provide quantitative evidence that the extent of Arctic shipping in the period 2011–2014 is already significant and that it is concentrated (i) in the Norwegian and Barents Seas, and (ii) predominantly accessed via the Northeast and Northwest Passages. Thick ice along the forecasted direct trans-Arctic route was still present in 2014, preventing transit. Although Arctic shipping remains constrained by the extent of ice coverage, during every September, this coverage is at a minimum, allowing the highest levels of shipping activity. Access to Arctic resources, particularly fisheries, is the most important driver of Arctic shipping thus far.

  11. Pipeline dreams: people, environment, and the Arctic energy frontier

    National Research Council Canada - National Science Library

    Nuttall, Mark


    "With a focus on the North American Arctic and sub-Arctic, this book discusses how dreams of extracting resource wealth have been significant in influencing and shaping relations between indigenous...

  12. Environmental Working Group Arctic Meteorology and Climate Atlas, Version 1 (United States)

    National Aeronautics and Space Administration — The Arctic Meteorology and Climate Atlas was developed by specialists from the Arctic and Antarctic Research Institute (AARI), St. Petersburg, Russia, the University...

  13. The Arctic DP Research Project: Effective Stationkeeping in Ice

    National Research Council Canada - National Science Library

    Skjetne, Roger; Imsland, Lars; Løset, Sveinung


    ... development that have successfully been used e.g. in the North Sea. The special edition of MIC on Arctic DP presents a set of articles that summarize to an extent the activities of the research project Arctic DP...

  14. The Arctic Region: A Requirement for New Security Architecture? (United States)


    Council as the only circumpolar body and the leading political body for Arctic issues38. Norway also intends to step up its efforts to focus attention on...5711 14. ABSTRACT Global interest in the Arctic will inevitably increase even more in the coming years. International interest in the Arctic manage. This requires a solid, effective regional and global cooperation that constantly adapts to new opportunities and conditions. The Arctic

  15. Arctic Security: An Adaptive Approach for a Changing Climate (United States)


    Europe would be most affected, becoming colder, drier, and windier, much like Siberia .22 This scenario is not as unlikely as it sounds. Climatic records...believe the Lomonosov Ridge, an underwater Arctic mountain range thought to roughly connect Siberia and Greenland, to be an extension of the Arctic; Emergency Prevention, Preparedness, and Response in the Arctic; and Conservation of Arctic Flora and Fauna . Building on this strategy

  16. Changing geo-political realities in the Arctic region

    DEFF Research Database (Denmark)

    Sørensen, Camilla T. N.


    This article analyzes and discusses how Denmark seeks to manage the changing geopolitical realities in the Arctic region specifically focusing on how Denmark seeks to manage its relations with China in the Arctic region.......This article analyzes and discusses how Denmark seeks to manage the changing geopolitical realities in the Arctic region specifically focusing on how Denmark seeks to manage its relations with China in the Arctic region....

  17. Prognostic Disclosures to Children: A Historical Perspective. (United States)

    Sisk, Bryan A; Bluebond-Langner, Myra; Wiener, Lori; Mack, Jennifer; Wolfe, Joanne


    Prognostic disclosure to children has perpetually challenged clinicians and parents. In this article, we review the historical literature on prognostic disclosure to children in the United States using cancer as an illness model. Before 1948, there was virtually no literature focused on prognostic disclosure to children. As articles began to be published in the 1950s and 1960s, many clinicians and researchers initially recommended a "protective" approach to disclosure, where children were shielded from the harms of bad news. We identified 4 main arguments in the literature at this time supporting this "protective" approach. By the late 1960s, however, a growing number of clinicians and researchers were recommending a more "open" approach, where children were included in discussions of diagnosis, which at the time was often synonymous with a terminal prognosis. Four different arguments in the literature were used at this time supporting this "open" approach. Then, by the late 1980s, the recommended approach to prognostic disclosure in pediatrics shifted largely from "never tell" to "always tell." In recent years, however, there has been a growing appreciation for the complexity of prognostic disclosure in pediatrics. Current understanding of pediatric disclosure does not lead to simple "black-and-white" recommendations for disclosure practices. As with most difficult questions, we are left to balance competing factors on a case-by-case basis. We highlight 4 categories of current considerations related to prognostic disclosure in pediatrics, and we offer several approaches to prognostic disclosure for clinicians who care for these young patients and their families. Copyright © 2016 by the American Academy of Pediatrics.

  18. Exploring Arctic Transpolar Drift During Dramatic Sea Ice Retreat

    DEFF Research Database (Denmark)

    Gascard, J.C.; Festy, J.; le Goff, H.


    The Arctic is undergoing significant environmental changes due to climate warming. The most evident signal of this warming is the shrinking and thinning of the ice cover of the Arctic Ocean. If the warming continues, as global climate models predict, the Arctic Ocean will change from a perennially...

  19. India and the Arctic: environment, economy and politics

    Directory of Open Access Journals (Sweden)

    Tatyana L. Shaumyan


    Full Text Available The article analyzes the main trends in the development of India and the development of the Arctic: the participation in the study of global warming and the state of the Arctic ice; the use of the Northern Sea Route for transportation; expansion of international cooperation in the Arctic direction, including with Russia.

  20. Romantic notions about the arctic must include indigenous rights

    DEFF Research Database (Denmark)

    Burke, Danita Catherine


    The Arctic plays a big role in Canada's national identity. But as Canada's relationship with the region evolves, the interests of Indigenous peoples must be better represented. This article summarizes the research in my book 'International Disputes and Cultural Ideas in the Canadian Arctic: Arctic...

  1. Establishing Shared Knowledge about Globalization in Asia and the Arctic

    DEFF Research Database (Denmark)

    Bertelsen, Rasmus Gjedssø; Graczyk, Piotr


    We discuss the role of knowledge in relations between Arctic communities and Asia (the Arctic Council observer states: China, India, Japan, Singapore, South Korea). We argue that mutual and shared knowledge between Arctic communities and Asia is necessary for local benefits and comprehensively...

  2. Arctic Ocean freshwater: How robust are model simulations?

    NARCIS (Netherlands)

    Jahn, A.; Aksenov, Y.; de Cuevas, B.A.; de Steur, L.; Häkkinen, S.; Hansen, E.; Herbaut, C.; Houssais, M.N.; Karcher, M.; Kauker, F.; Lique, C.; Nguyen, A.; Pemberton, P.; Worthen, D.; Zhang, J.


    The Arctic freshwater (FW) has been the focus of many modeling studies, due to the potential impact of Arctic FW on the deep water formation in the North Atlantic. A comparison of the hindcasts from ten ocean-sea ice models shows that the simulation of the Arctic FW budget is quite different in the

  3. Arctic Ocean Paleoceanography and Future IODP Drilling (United States)

    Stein, Ruediger


    Although the Arctic Ocean is a major player in the global climate/earth system, this region is one of the last major physiographic provinces on Earth where the short- and long-term geological history is still poorly known. This lack in knowledge is mainly due to the major technological/logistical problems in operating within the permanently ice-covered Arctic region which makes it difficult to retrieve long and undisturbed sediment cores. Prior to 2004, in the central Arctic Ocean piston and gravity coring was mainly restricted to obtaining near-surface sediments, i.e., only the upper 15 m could be sampled. Thus, all studies were restricted to the late Pliocene/Quaternary time interval, with a few exceptions. These include the four short cores obtained by gravity coring from drifting ice floes over the Alpha Ridge, where older pre-Neogene organic-carbon-rich muds and laminated biosiliceous oozes were sampled. Continuous central Arctic Ocean sedimentary records, allowing a development of chronologic sequences of climate and environmental change through Cenozoic times and a comparison with global climate records, however, were missing prior to the IODP Expedition 302 (Arctic Ocean Coring Expedition - ACEX), the first scientific drilling in the central Arctic Ocean. By studying the unique ACEX sequence, a large number of scientific discoveries that describe previously unknown Arctic paleoenvironments, were obtained during the last decade (for most recent review and references see Stein et al., 2014). While these results from ACEX were unprecedented, key questions related to the climate history of the Arctic Ocean remain unanswered, in part because of poor core recovery, and in part because of the possible presence of a major mid-Cenozoic hiatus or interval of starved sedimentation within the ACEX record. In order to fill this gap in knowledge, international, multidisciplinary expeditions and projects for scientific drilling/coring in the Arctic Ocean are needed. Key

  4. SubArctic Oceans and Global Climate (United States)

    Rhines, P. B.


    The passages connecting the Arctic Ocean with the Atlantic and Pacific, and their `mediterranean' basins, are focal points for the global meridional overturning circulation, and all of the climate impacts which this implies. It is also a difficult region to model accurately: the sensitivity of climate models to subpolar ocean dynamics is well-known. In this talk we stress the need to instrument and analyze the subpolar oceans, and some examples of sustained observations developing there. Results from satellite altimetry, recent Seaglider deployments from Greenland, and mooring arrays will be described. In particular we show the first Seaglider sections of hydrography and bio-optical profiles of the Labrador Sea (one of the first extended deployments of this autonomous undersea vehicle); we discuss the decline during the 1990s of the subpolar gyre circulation of the Atlantic from its great strength during the positive NAO period of the early 1990s, and its relevance to the salinity decline observed over a much longer period; we review observations of the flows at the Iceland-Scotland Ridge and Davis Strait, argued in terms of volume transport plots on the potential temperature/salinity plane; we display maps of the `convection resistance' (related to dynamic height) and its sensitivity to surface low-salinity water masses and their partition between shallow continental shelves and deep ocean. This is a particularly exciting time for climate studies, with fundamental properties of the atmosphere-ocean circulation under debate, even before one considers natural and human-induced variability. Is the four-decade long decline in subArctic salinity the result of increased hydrologic cycle, increased or altered Arctic outflow to the Atlantic, or slowing of the subpolar circulation? Is the basic intensity of the MOC more dependent on high-latitude buoyancy forcing, or wind- or tide-driven mixing in the upwelling branch, or possibly wind-stress at high latitude? Is the

  5. Arctic shipping emissions inventories and future scenarios

    Directory of Open Access Journals (Sweden)

    J. J. Corbett


    Full Text Available This paper presents 5 km×5 km Arctic emissions inventories of important greenhouse gases, black carbon and other pollutants under existing and future (2050 scenarios that account for growth of shipping in the region, potential diversion traffic through emerging routes, and possible emissions control measures. These high-resolution, geospatial emissions inventories for shipping can be used to evaluate Arctic climate sensitivity to black carbon (a short-lived climate forcing pollutant especially effective in accelerating the melting of ice and snow, aerosols, and gaseous emissions including carbon dioxide. We quantify ship emissions scenarios which are expected to increase as declining sea ice coverage due to climate change allows for increased shipping activity in the Arctic. A first-order calculation of global warming potential due to 2030 emissions in the high-growth scenario suggests that short-lived forcing of ~4.5 gigagrams of black carbon from Arctic shipping may increase global warming potential due to Arctic ships' CO2 emissions (~42 000 gigagrams by some 17% to 78%. The paper also presents maximum feasible reduction scenarios for black carbon in particular. These emissions reduction scenarios will enable scientists and policymakers to evaluate the efficacy and benefits of technological controls for black carbon, and other pollutants from ships.

  6. Arctic Observing Experiment (AOX) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Rigor, Ignatius [Applied Physics Lab, University of Washington; Johnson, Jim [Applied Physics Lab, University of Washington; Motz, Emily [National Ice Center; Bisic, Aaron [National Ice Center


    Our ability to understand and predict weather and climate requires an accurate observing network. One of the pillars of this network is the observation of the fundamental meteorological parameters: temperature, air pressure, and wind. We plan to assess our ability to measure these parameters for the polar regions during the Arctic Observing Experiment (AOX, Figure 1) to support the International Arctic Buoy Programme (IABP), Arctic Observing Network (AON), International Program for Antarctic Buoys (IPAB), and Southern Ocean Observing System (SOOS). Accurate temperature measurements are also necessary to validate and improve satellite measurements of surface temperature across the Arctic. Support for research associated with the campaign is provided by the National Science Foundation, and by other US agencies contributing to the US Interagency Arctic Buoy Program. In addition to the support provided by the U.S Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s North Slope of Alaska (NSA) site at Barrow and the National Science Foundation (NSF), the U.S. IABP is supported by the U.S. Coast Guard (USCG), the National Aeronautics and Space Administration (NASA), the National Ice Center (NIC), the National Oceanic and Atmospheric Administration (NOAA), and the Office of Naval Research (ONR).

  7. Heterotrophic protists in the Central Arctic Ocean (United States)

    Sherr, Evelyn B.; Sherr, Barry F.; Fessenden, Lynne

    Distribution, general composition and activity of heterotrophic protists, as well as the distribution of bacteria, were assessed in the upper water column of the central Arctic Ocean during the Arctic Ocean Section, July-September 1994. Bacterial biomass varied from 5 to > 25 mg C 1 -1, with the highest values occurring in the Chukchi Sea. Protist biomass was highest (5-107 mg Cl -1) in the upper 50 m of the water column. Higher integrated (0-50 m) protist biomass values (average 910±250 mg C m -2, range 580-1370 mg C m -2) were found in the Chukchi Sea, compared to the central Arctic Ocean (average 480±320 mg C m -2, range 120-1120 mg C m -2). Heterotrophic dinoflagellates were more abundant than ciliates in the >20 μm size class at all stations. In the central Arctic Ocean, the cryptomonads and diatoms, as well as pico-autotrophs. Clearance rates of 10-100 μm sized ciliates and dinoflagellates, based on the uptake of 1-5 μm fluorescent microspheres, were similar to rates reported for herbivorous protists in temperate waters. In terms of ecosystem carbon flow, we infer that phagotrophic protists in the Arctic Ocean are important consumers of phytoplankton and bacteria, and may represent a significant food resource for zooplankton.

  8. 2nd International Arctic Ungulate Conference

    Directory of Open Access Journals (Sweden)

    A. Anonymous


    Full Text Available The 2nd International Arctic Ungulate Conference was held 13-17 August 1995 on the University of Alaska Fairbanks campus. The Institute of Arctic Biology and the Alaska Cooperative Fish and Wildlife Research Unit were responsible for organizing the conference with assistance from biologists with state and federal agencies and commercial organizations. David R. Klein was chair of the conference organizing committee. Over 200 people attended the conference, coming from 10 different countries. The United States, Canada, and Norway had the largest representation. The conference included invited lectures; panel discussions, and about 125 contributed papers. There were five technical sessions on Physiology and Body Condition; Habitat Relationships; Population Dynamics and Management; Behavior, Genetics and Evolution; and Reindeer and Muskox Husbandry. Three panel sessions discussed Comparative caribou management strategies; Management of introduced, reestablished, and expanding muskox populations; and Health risks in translocation of arctic ungulates. Invited lectures focused on the physiology and population dynamics of arctic ungulates; contaminants in food chains of arctic ungulates and lessons learned from the Chernobyl accident; and ecosystem level relationships of the Porcupine Caribou Herd.

  9. Debating the Arctic during the Ukraine Crisis – Comparing Arctic State Identities and Media Discourses in Canada and Norway

    DEFF Research Database (Denmark)

    Burke, Danita Catherine; Rahbek-Clemmensen, Jon


    Previous studies have argued that domestic factors, including each state’s Arctic state identities, may explain why some Western states (e.g. Canada) have been more critical of Russia in the Arctic than others (e.g. Norway). The present study analyses part of the link between Arctic state identit...

  10. Arctic Infrastructures: Tele Field Notes

    Directory of Open Access Journals (Sweden)

    Rafico Ruiz


    Full Text Available This article contextualizes the conditions of rural “connectivity” in the Canadian Arctic. It examines the emergence of satellites, fibre optic cables, and intranets as modes of social infrastructure at the outset of the twenty-first century. At present, Nunavut, the Northwest Territories, and the Yukon are all at a complicated confluence in that their current and inadequate telecommunications infrastructures are in the process of being renegotiated, re-designed, and re-allotted across civic, governmental, and corporate interests. The article shows how it is at sites of friction that the overlapping if fading legacies of systems-based thinking are emerging: satellites orbiting over fibre optic cable lines; corporate actors competing rather than coordinating with government agencies; and neoliberal rationales of mapping, division, and speed creating disjointed local markets. More broadly, these sites also demonstrate how indigenous forms of “connection” across the globe are increasingly experiencing telecommunications’ lags and temporal disjunctures that are having very material effects on their supposedly post-colonial lives.

  11. Prognostic DNA Methylation Markers for Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Siri H. Strand


    Full Text Available Prostate cancer (PC is the most commonly diagnosed neoplasm and the third most common cause of cancer-related death amongst men in the Western world. PC is a clinically highly heterogeneous disease, and distinction between aggressive and indolent disease is a major challenge for the management of PC. Currently, no biomarkers or prognostic tools are able to accurately predict tumor progression at the time of diagnosis. Thus, improved biomarkers for PC prognosis are urgently needed. This review focuses on the prognostic potential of DNA methylation biomarkers for PC. Epigenetic changes are hallmarks of PC and associated with malignant initiation as well as tumor progression. Moreover, DNA methylation is the most frequently studied epigenetic alteration in PC, and the prognostic potential of DNA methylation markers for PC has been demonstrated in multiple studies. The most promising methylation marker candidates identified so far include PITX2, C1orf114 (CCDC181 and the GABRE~miR-452~miR-224 locus, in addition to the three-gene signature AOX1/C1orf114/HAPLN3. Several other biomarker candidates have also been investigated, but with less stringent clinical validation and/or conflicting evidence regarding their possible prognostic value available at this time. Here, we review the current evidence for the prognostic potential of DNA methylation markers in PC.

  12. A Distributed Prognostic Health Management Architecture (United States)

    Bhaskar, Saha; Saha, Sankalita; Goebel, Kai


    This paper introduces a generic distributed prognostic health management (PHM) architecture with specific application to the electrical power systems domain. Current state-of-the-art PHM systems are mostly centralized in nature, where all the processing is reliant on a single processor. This can lead to loss of functionality in case of a crash of the central processor or monitor. Furthermore, with increases in the volume of sensor data as well as the complexity of algorithms, traditional centralized systems become unsuitable for successful deployment, and efficient distributed architectures are required. A distributed architecture though, is not effective unless there is an algorithmic framework to take advantage of its unique abilities. The health management paradigm envisaged here incorporates a heterogeneous set of system components monitored by a varied suite of sensors and a particle filtering (PF) framework that has the power and the flexibility to adapt to the different diagnostic and prognostic needs. Both the diagnostic and prognostic tasks are formulated as a particle filtering problem in order to explicitly represent and manage uncertainties; however, typically the complexity of the prognostic routine is higher than the computational power of one computational element ( CE). Individual CEs run diagnostic routines until the system variable being monitored crosses beyond a nominal threshold, upon which it coordinates with other networked CEs to run the prognostic routine in a distributed fashion. Implementation results from a network of distributed embedded devices monitoring a prototypical aircraft electrical power system are presented, where the CEs are Sun Microsystems Small Programmable Object Technology (SPOT) devices.

  13. Prognostic modeling in pediatric acute liver failure. (United States)

    Jain, Vandana; Dhawan, Anil


    Liver transplantation (LT) is the only proven treatment for pediatric acute liver failure (PALF). However, over a period of time, spontaneous native liver survival is increasingly reported, making us wonder if we are overtransplanting children with acute liver failure (ALF). An effective prognostic model for PALF would help direct appropriate organ allocation. Only patients who would die would undergo LT, and those who would spontaneously recover would avoid unnecessary LT. Deriving and validating such a model for PALF, however, encompasses numerous challenges. In particular, the heterogeneity of age and etiology in PALF, as well as a lack of understanding of the natural history of the disease, contributed by the availability of LT has led to difficulties in prognostic model development. Several prognostic laboratory variables have been identified, and the incorporation of these variables into scoring systems has been attempted. A reliable targeted prognostic model for ALF in Wilson's disease has been established and externally validated. The roles of physiological, immunological, and metabolomic parameters in prognosis are being investigated. This review discusses the challenges with prognostic modeling in PALF and describes predictive methods that are currently available and in development for the future. Liver Transplantation 22 1418-1430 2016 AASLD. © 2016 by the American Association for the Study of Liver Diseases.



    Hoffmann, Matthias H.; von Hagen, K. Bernhard; Hörandl, Elvira; Röser, Martin; Tkach, Natalia V.


    The arctic biome is a relatively young ecosystem with ~2300 species of vascular plants. We studied the genus Ranunculus as an example of the origin and evolution of the arctic flora. For this purpose we used molecular phylogenetic and clock analyses based on evaluation of nuclear ITS and chloroplast matK-trnK DNA sequences in 194 taxa of Ranunculus and closely related genera. Taxa occurring in the Arctic arose form seven phylogenetic lineages of Ranunculus and also in the genera Coptidium and...

  15. Leading in the Arctic; Translating the United States Arctic Strategy into Opportunities for Peace and Stability (United States)


    Russia.14 The Arctic still provides a short route to other critical parts of the northern hemisphere today and serves as a physical barrier the southern route that goes through the Suez canal.” This change could save approximately “1,000 tons fuel (valued at 650,000)” per ship and cuts...Climatology and Meteorology , 2016. meteorology /climate_vs_weather.html 21. Encyclopædia Britannica Online. "Arctic map

  16. AROME-Arctic: New operational NWP model for the Arctic region (United States)

    Süld, Jakob; Dale, Knut S.; Myrland, Espen; Batrak, Yurii; Homleid, Mariken; Valkonen, Teresa; Seierstad, Ivar A.; Randriamampianina, Roger


    In the frame of the EU-funded project ACCESS (Arctic Climate Change, Economy and Society), MET Norway aimed 1) to describe the present monitoring and forecasting capabilities in the Arctic; and 2) to identify the key factors limiting the forecasting capabilities and to give recommendations on key areas to improve the forecasting capabilities in the Arctic. We have observed that the NWP forecast quality is lower in the Arctic than in the regions further south. Earlier research indicated that one of the factors behind this is the composition of the observing system in the Arctic, in particular the scarceness of conventional observations. To further assess possible strategies for alleviating the situation and propose scenarios for a future Arctic observing system, we have performed a set of experiments to gain a more detailed insight in the contribution of the components of the present observing system in a regional state-of-the-art non-hydrostatic NWP model using the AROME physics (Seity et al, 2011) at 2.5 km horizontal resolution - AROME-Arctic. Our observing system experiment studies showed that conventional observations (Synop, Buoys) can play an important role in correcting the surface state of the model, but prove that the present upper-air conventional (Radiosondes, Aircraft) observations in the area are too scarce to have a significant effect on forecasts. We demonstrate that satellite sounding data play an important role in improving forecast quality. This is the case with satellite temperature sounding data (AMSU-A, IASI), as well as with the satellite moisture sounding data (AMSU-B/MHS, IASI). With these sets of observations, the AROME-Arctic clearly performs better in forecasting extreme events, like for example polar lows. For more details see presentation by Randriamampianina et al. in this session. The encouraging performance of AROME-Arctic lead us to implement it with more observations and improved settings into daily runs with the objective to

  17. Quantum imaging for underwater arctic navigation (United States)

    Lanzagorta, Marco


    The precise navigation of underwater vehicles is a difficult task due to the challenges imposed by the variable oceanic environment. It is particularly difficult if the underwater vehicle is trying to navigate under the Arctic ice shelf. Indeed, in this scenario traditional navigation devices such as GPS, compasses and gyrocompasses are unavailable or unreliable. In addition, the shape and thickness of the ice shelf is variable throughout the year. Current Arctic underwater navigation systems include sonar arrays to detect the proximity to the ice. However, these systems are undesirable in a wartime environment, as the sound gives away the position of the underwater vehicle. In this paper we briefly describe the theoretical design of a quantum imaging system that could allow the safe and stealthy navigation of underwater Arctic vehicles.

  18. Arctic Ozone Depletion from UARS MLS Measurements (United States)

    Manney, G. L.


    Microwave Limb Sounder (MLS) measurements of ozone during four Arctic winters are compared. The evolution of ozone in the lower stratosphere is related to temperature, chlorine monoxide (also measured by MLS), and the evolution of the polar vortex. Lagrangian transport calculations using winds from the United Kingdom Meteorological Office's Stratosphere-Troposphere Data Assimilation system are used to estimate to what extent the evolution of lower stratospheric ozone is controlled by dynamics. Observations, along with calculations of the expected dynamical behavior, show evidence for chemical ozone depletion throughout most of the Arctic lower stratospheric vortex during the 1992-93 middle and late winter, and during all of the 1994-95 winter that was observed by MLS. Both of these winters were unusually cold and had unusually cold and had unusually strong Arctic polar vortices compared to meteorological data over the past 17 years.

  19. Projections and predictability of Arctic shipping accessibility (United States)

    Melia, Nathanael; Haines, Keith; Hawkins, Ed


    The observed reduction in Arctic sea ice opens up the potential for shorter shipping routes across the Arctic Ocean, leading to potentially significant global economic savings. We demonstrate, using bias-corrected global climate models, that the projected sea ice melt through the 21st century increases opportunities for ships to sail through the Arctic between North Atlantic and East Asian ports. Transit potential for Open Water vessels doubles from early to mid-century and coincides with the opening of the trans-polar sea route. Although seasonal, routes become more reliable with an overall increased shipping season length, but with considerable variability from year-to-year. We also demonstrate that there is potential predictability for whether a particular season will be relatively open or closed to shipping access from a few months ahead.


    Hoffmann, Matthias H.; von Hagen, K. Bernhard; Hörandl, Elvira; Röser, Martin; Tkach, Natalia V.


    The arctic biome is a relatively young ecosystem with ~2300 species of vascular plants. We studied the genus Ranunculus as an example of the origin and evolution of the arctic flora. For this purpose we used molecular phylogenetic and clock analyses based on evaluation of nuclear ITS and chloroplast matK-trnK DNA sequences in 194 taxa of Ranunculus and closely related genera. Taxa occurring in the Arctic arose form seven phylogenetic lineages of Ranunculus and also in the genera Coptidium and Halerpestes. Two clades of Ranunculus are species-rich in the Arctic, i.e., Ranunculus sect. Ranunculus and R. sect. Auricomus (both from R. subg. Ranunculus), but this is due to a number of arctic “microtaxa” morphologically barely separate from R. acris in the former clade and the widely agamospermic species complex of R. auricomus in the latter. Lineages with species adapted to wetlands or aquatic habitats are significant groups represented in the arctic flora (R. subg. Ranunculus sectt. Flammula and Hecatonia/Xanthobatrachium, R. subg. Batrachium, genus Coptidium) but show no clear signs of radiation in the Arctic or the northern boreal zone, except for sectt. Hecatonia/Xanthobatrachium, with R. hyperboreus and R. sceleratus subsp. reptabundus. Astonishingly few of the otherwise numerous lineages of Ranunculus with distributions in the higher mountain systems of Eurasia and North America have acted as “founding sources” for the arctic flora. The only clear example is that of the arctic-alpine R. glacialis and the Beringian R. chamissonis from the lineage of subg. R. sectt. Aconitifolii/Crymodes, although there might be others in sect. Auricomus not recovered in the current molecular data. Lineages that gave rise to arctic taxa diverged from each other from the early Miocene (R. glacialis/R. chamissonis, Coptidium, lineages in Halerpestes) and continued at an even rate throughout the Tertiary. There are no signs that the intense climate changes of the late Pliocene

  1. Active molecular iodine photochemistry in the Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Raso, Angela R.; Custard, Kyle D.; May, Nathaniel W.; Tanner, David; Newburn, Matthew K.; Walker, Lawrence R.; Moore, Ronald J.; Huey, L. G.; Alexander, Lizabeth; Shepson, Paul B.; Pratt, Kerri A.


    During springtime, the Arctic atmospheric boundary layer undergoes frequent rapid depletions in ozone and gaseous elemental mercury due to reactions with halogen atoms, influencing atmospheric composition and pollutant fate. Although bromine chemistry has been shown to initiate ozone depletion events, and it has long been hypothesized that iodine chemistry may contribute, no previous measurements of molecular iodine (I2) have been reported in the Arctic. Iodine chemistry also contributes to atmospheric new particle formation and therefore cloud properties and radiative forcing. Here we present Arctic atmospheric I2 and snowpack iodide (I-) measurements, which were conducted near Utqiagvik, AK, in February 2014. Using chemical ionization mass spectrometry, I2 was observed in the atmosphere at mole ratios of 0.3–1.0 ppt, and in the snowpack interstitial air at mole ratios up to 22 ppt under natural sunlit conditions and up to 35 ppt when the snowpack surface was artificially irradiated, suggesting a photochemical production mechanism. Further, snow meltwater I-measurements showed enrichments of up to ~1,900 times above the seawater ratio of I-/Na+, consistent with iodine activation and recycling. Modeling shows that observed I2 levels are able to significantly increase ozone depletion rates, while also producing iodine monoxide (IO) at levels recently observed in the Arctic. These results emphasize the significance of iodine chemistry and the role of snowpack photochemistry in Arctic atmospheric composition, and imply that I2 is likely a dominant source of iodine atoms in the Arctic.

  2. Export of nutrients from the Arctic Ocean (United States)

    Torres-Valdés, Sinhué; Tsubouchi, Takamasa; Bacon, Sheldon; Naveira-Garabato, Alberto C.; Sanders, Richards; McLaughlin, Fiona A.; Petrie, Brian; Kattner, Gerhard; Azetsu-Scott, Kumiko; Whitledge, Terry E.


    study provides the first physically based mass-balanced transport estimates of dissolved inorganic nutrients (nitrate, phosphate, and silicate) for the Arctic Ocean. Using an inverse model-generated velocity field in combination with a quasi-synoptic assemblage of hydrographic and hydrochemical data, we quantify nutrient transports across the main Arctic Ocean gateways: Davis Strait, Fram Strait, the Barents Sea Opening (BSO), and Bering Strait. We found that the major exports of all three nutrients occur via Davis Strait. Transports associated with the East Greenland Current are almost balanced by transports associated with the West Spitsbergen Current. The most important imports of nitrate and phosphate to the Arctic occur via the BSO, and the most important import of silicate occurs via Bering Strait. Oceanic budgets show that statistically robust net silicate and phosphate exports exist, while the net nitrate flux is zero, within the uncertainty limits. The Arctic Ocean is a net exporter of silicate (-15.7 ± 3.2 kmol s-1) and phosphate (-1.0 ± 0.3 kmol s-1; net ± 1 standard error) to the North Atlantic. The export of excess phosphate (relative to nitrate) from the Arctic, calculated at -1.1 ± 0.3 kmol s-1, is almost twice as large as previously estimated. Net transports of silicate and phosphate from the Arctic Ocean provide 12% and 90%, respectively, of the net southward fluxes estimated at 47°N in the North Atlantic. Additional sources of nutrients that may offset nutrient imbalances are explored, and the relevance and the pathway of nutrient transports to the North Atlantic are discussed.

  3. Polydactyly in Arctic foxes (Vulpes lagopus)




    Seven Arctic fox puppies were found to have an extra claw (resembling a canine dewclaw) on their thoracic limb. These individuals came from 2 litters born of 2 different females. The "dewclaw" comprised a claw loosely connected with the limb by soft tissue, and it had the third phalanx (PIII) and a vestigial phalanx. Our results show that the presence of an extra claw on one or both hands in some Arctic fox puppies may, but does not have to, be a dominant trait. The differen...

  4. Monitoring the melting of the Arctic (United States)

    Kalaugher, Liz


    Standing on the deck of the icebreaker Amundsen in the Arctic Ocean, I am bathed in blazing June sunshine. The weather has been like this all week since I joined the ship - a research vessel that set sail from Quebec in Canada last summer - as a visiting science journalist. It would be tempting to think that such conditions are typical, but most areas of the Arctic are in fact cloudy for 80% of the time in the spring and summer due to moisture in the air from melting ice and from exposed areas of the ocean.

  5. Massive phytoplankton blooms under Arctic sea ice. (United States)

    Arrigo, Kevin R; Perovich, Donald K; Pickart, Robert S; Brown, Zachary W; van Dijken, Gert L; Lowry, Kate E; Mills, Matthew M; Palmer, Molly A; Balch, William M; Bahr, Frank; Bates, Nicholas R; Benitez-Nelson, Claudia; Bowler, Bruce; Brownlee, Emily; Ehn, Jens K; Frey, Karen E; Garley, Rebecca; Laney, Samuel R; Lubelczyk, Laura; Mathis, Jeremy; Matsuoka, Atsushi; Mitchell, B Greg; Moore, G W K; Ortega-Retuerta, Eva; Pal, Sharmila; Polashenski, Chris M; Reynolds, Rick A; Schieber, Brian; Sosik, Heidi M; Stephens, Michael; Swift, James H


    Phytoplankton blooms over Arctic Ocean continental shelves are thought to be restricted to waters free of sea ice. Here, we document a massive phytoplankton bloom beneath fully consolidated pack ice far from the ice edge in the Chukchi Sea, where light transmission has increased in recent decades because of thinning ice cover and proliferation of melt ponds. The bloom was characterized by high diatom biomass and rates of growth and primary production. Evidence suggests that under-ice phytoplankton blooms may be more widespread over nutrient-rich Arctic continental shelves and that satellite-based estimates of annual primary production in these waters may be underestimated by up to 10-fold.

  6. The role of the Arctic in future global petroleum supply

    Energy Technology Data Exchange (ETDEWEB)

    Lindholt, Lars; Glomsroed, Solveig


    The Arctic has a substantial share of global petroleum resources, but at higher costs than in most other petroleum provinces. Arctic states and petroleum companies are carefully considering the potential for future extraction in the Arctic. This paper studies the oil and gas supply from 6 arctic regions during 2010-2050 along with global economic growth and different assumptions regarding petroleum prices and resource endowments. Supply is calculated based on a global model of oil and gas markets. The data on undiscovered resources for the Arctic is based on the estimates by USGS. Sensitivity studies are carried out for two alternative price scenarios and for a 50 per cent reduction of arctic undiscovered resources compared with the USGS 2008 resource estimate. Although a major part of the undiscovered arctic petroleum resources is natural gas, our results show that the relative importance of the Arctic as a world gas supplier will decline, while its importance as a global oil producer may be maintained. We also show that less than full access to undiscovered oil resources will have minor effect on total arctic oil production and a marginal effect on arctic gas extraction. The reason is that Arctic Russia is an important petroleum producer with a sufficiently large stock of already discovered resources to support their petroleum production before 2050. (Author)

  7. Climate Change, Globalization and Geopolitics in the New Maritime Arctic (United States)

    Brigham, L. W.


    Early in the 21st century a confluence of climate change, globalization and geopolitics is shaping the future of the maritime Arctic. This nexus is also fostering greater linkage of the Arctic to the rest of the planet. Arctic sea ice is undergoing a historic transformation of thinning, extent reduction in all seasons, and reduction in the area of multiyear ice in the central Arctic Ocean. Global Climate Model simulations of Arctic sea ice indicate multiyear ice could disappear by 2030 for a short period of time each summer. These physical changes invite greater marine access, longer seasons of navigation, and potential, summer trans-Arctic voyages. As a result, enhanced marine safety, environmental protection, and maritime security measures are under development. Coupled with climate change as a key driver of regional change is the current and future integration of the Arctic's natural wealth with global markets (oil, gas and hard minerals). Abundant freshwater in the Arctic could also be a future commodity of value. Recent events such as drilling for hydrocarbons off Greenland's west coast and the summer marine transport of natural resources from the Russian Arctic to China across the top of Eurasia are indicators of greater global economic ties to the Arctic. Plausible Arctic futures indicate continued integration with global issues and increased complexity of a range of regional economic, security and environmental challenges.

  8. Migration and breeding biology of Arctic terns in Greenland

    DEFF Research Database (Denmark)

    Egevang, Carsten

    , the study produced the first estimates of the key prey species of the Arctic tern in Greenland. Although zooplankton and various fish species were present in the chick diet of terns breeding in Disko Bay, Capelin (Mallotus villosus) was the single most important prey species found in all age groups...... (Sandøen) in high-Arctic Northeast Greenland. The level of knowledge of the Arctic tern in Greenland before 2002 was to a large extent poor, with aspects of its biology being completely unknown in the Greenland population. This thesis presents novel findings for the Arctic tern, both on an international...... by the distribution of breeding Arctic terns as suggested by Egevang et al. (2004). Included in the thesis are furthermore results with an appeal to the Greenland management agencies. Along with estimates of the Arctic tern population size at the two most important Arctic tern colonies in West Greenland and East...

  9. Migration and breeding biology of arctic terns in Greenland

    DEFF Research Database (Denmark)

    Egevang, Carsten

    , the study produced the first estimates of the key prey species of the Arctic tern in Greenland. Although zooplankton and various fish species were present in the chick diet of terns breeding in Disko Bay, Capelin (Mallotus villosus) was the single most important prey species found in all age groups...... (Sandøen) in high-Arctic Northeast Greenland. The level of knowledge of the Arctic tern in Greenland before 2002 was to a large extent poor, with aspects of its biology being completely unknown in the Greenland population. This thesis presents novel findings for the Arctic tern, both on an international...... by the distribution of breeding Arctic terns as suggested by Egevang et al. (2004). Included in the thesis are furthermore results with an appeal to the Greenland management agencies. Along with estimates of the Arctic tern population size at the two most important Arctic tern colonies in West Greenland and East...

  10. Arctic security in an age of climate change

    Energy Technology Data Exchange (ETDEWEB)

    Kraska, James (ed.)


    Publisher review: This book examines Arctic defense policy and military security from the perspective of all eight Arctic states. In light of climate change and melting ice in the Arctic Ocean, Canada, Russia, Denmark (Greenland), Norway and the United States, as well as Iceland, Sweden and Finland, are grappling with an emerging Arctic security paradigm. This volume brings together the world's most seasoned Arctic political-military experts from Europe and North America to analyze how Arctic nations are adapting their security postures to accommodate increased shipping, expanding naval presence, and energy and mineral development in the polar region. The book analyzes the ascent of Russia as the first 'Arctic superpower', the growing importance of polar security for NATO and the Nordic states, and the increasing role of Canada and the United States in the region.(Author)

  11. A Model-based Prognostics Approach Applied to Pneumatic Valves (United States)

    National Aeronautics and Space Administration — Within the area of systems health management, the task of prognostics centers on predicting when components will fail. Model-based prognostics exploits domain...

  12. Prognostics-Enabled Power Supply for ADAPT Testbed Project (United States)

    National Aeronautics and Space Administration — Ridgetop's role is to develop electronic prognostics for sensing power systems in support of NASA/Ames ADAPT testbed. The prognostic enabled power systems from...

  13. A Model-Based Prognostics Approach Applied to Pneumatic Valves (United States)

    National Aeronautics and Space Administration — Within the area of systems health management, the task of prognostics centers on predicting when components will fail. Model-based prognostics exploits domain...


    Directory of Open Access Journals (Sweden)

    B. M. Ahmed


    Conclusions. CD56 antigenic expression in AML cases represents an adverse prognostic factor. It should be regularly investigated in cases of AML for better prognostic stratification and assessment. KEY WORDS: CD56; leukemia, myeloid; prognosis

  15. Distributed Prognostics System Implementation on Wireless Embedded Devices (United States)

    National Aeronautics and Space Administration — Distributed prognostics is the next step in the evolution of prognostic methodologies. It is an important enabling technology for the emerging Condition Based...

  16. Communication Optimizations for a Wireless Distributed Prognostic Framework (United States)

    National Aeronautics and Space Administration — Distributed architecture for prognostics is an essential step in prognostic research in order to enable feasible real-time system health management. Communication...

  17. Arctic Health Research Center report no. 101: Combating mosquitoes in arctic Alaska (United States)

    US Fish and Wildlife Service, Department of the Interior — This report covers combating mosquitoes in Arctic Alaska. The physiology and biology of mosquitoes is discussed, followed by techniques to combated mosquitoes.

  18. About scavenging of near-water submicrometer aerosol in Arctic and Sub-Arctic regions (United States)

    Polkin, V. V.; Polkin, Vas. V.


    Situations with scavenging of submicrometer aerosol particles by precipitation are analyzed. Experiments were carries out in Arctic region (NABOS expedition) onboard research vessels "Akademik Fedorov" and "Professor Khlyustin" in August-September 2013.

  19. Chapter 3: Circum-Arctic mapping project: New magnetic and gravity anomaly maps of the Arctic (United States)

    Gaina, C.; Werner, S.C.; Saltus, R.; Maus, S.; Aaro, S.; Damaske, D.; Forsberg, R.; Glebovsky, V.; Johnson, K.; Jonberger, J.; Koren, T.; Korhonen, J.; Litvinova, T.; Oakey, G.; Olesen, O.; Petrov, O.; Pilkington, M.; Rasmussen, T.; Schreckenberger, B.; Smelror, M.


    New Circum-Arctic maps of magnetic and gravity anomalies have been produced by merging regional gridded data. Satellite magnetic and gravity data were used for quality control of the long wavelengths of the new compilations. The new Circum-Arctic digital compilations of magnetic, gravity and some of their derivatives have been analyzed together with other freely available regional and global data and models in order to provide a consistent view of the tectonically complex Arctic basins and surrounding continents. Sharp, linear contrasts between deeply buried basement blocks with different magnetic properties and densities that can be identified on these maps can be used, together with other geological and geophysical information, to refine the tectonic boundaries of the Arctic domain. ?? 2011 The Geological Society of London.

  20. Arctic Ocean, Spring 2008: What's left after the minimum ice extent of 2007? (United States)

    Morison, J.; Aagaard, K.; Alkire, M.; Collier, B.; Krishfield, R.; McPhee, M.; Moritz, D.; Overland, J.; Proshutinsky, A.; Kikuchi, T.; Smethie, B.; Steele, M.; Toole, J.


    On the heels of a record minimum ice extent in September 2007, unique changes were observed in the central Arctic Ocean and Beaufort Sea in spring 2008 as part of collaboration amongst the North Pole Environmental Observatory (NPEO), Beaufort Gyre Exploration Project (BGEP), Ice Tethered Profiler (ITP) and Switchyard programs. NPEO includes an automated drifting station that samples air-ice-ocean conditions while drifting from the Pole toward Fram Strait plus a deep ocean mooring near the Pole. NPEO and the Switchyard program also include repeated airborne hydrographic surveys that track changes along sections radiating from the Pole and north from Ellesmere Island. For IPY, the airborne survey was expanded to include the Beaufort Sea sections of BGEP, with the spring samples giving a seasonal counterpoint to the BGEP summer ship-based surveys. Most of the airborne stations were done with a ski-equipped aircraft landed on the sea ice to take water samples and CTD, oxygen and nutrient profiles. The most remote stations were made using new Air eXpendable CTDs (AXCTD) dropped in leads from an over-flying aircraft. The most remarkable difference from past years was the dominance of first-year ice in most areas, typically a little less than 2 m thick with relatively little snow cover. The Web cameras at the NPEO automated drifting station suggest that the lack of snow may have reduced ice melt. When the snow melted, water appeared to drain through the ice quickly, leaving the ice surface with few melt ponds and a relatively high-albedo appearance. This process, if it was widespread, may have helped more first year ice to survive the summer of 2008 than expected. In 2008, as in 2007, the NPEO ice mass balance buoy showed mostly top melt in spite of colder than normal air temperatures. Similar buoys in the Beaufort Sea showed mostly bottom melt. Near the Pole, upper ocean salinities and Atlantic Water temperatures increased in the early 1990s as the pattern of water

  1. Mixing rates and vertical heat fluxes north of Svalbard from Arctic winter to spring (United States)

    Meyer, Amelie; Fer, Ilker; Sundfjord, Arild; Peterson, Algot K.


    Mixing and heat flux rates collected in the Eurasian Basin north of Svalbard during the N-ICE2015 drift expedition are presented. The observations cover the deep Nansen Basin, the Svalbard continental slope, and the shallow Yermak Plateau from winter to summer. Mean quiescent winter heat flux values in the Nansen Basin are 2 W m-2 at the ice-ocean interface, 3 W m-2 in the pycnocline, and 1 W m-2 below the pycnocline. Large heat fluxes exceeding 300 W m-2 are observed in the late spring close to the surface over the Yermak Plateau. The data consisting of 588 microstructure profiles and 50 days of high-resolution under-ice turbulence measurements are used to quantify the impact of several forcing factors on turbulent dissipation and heat flux rates. Wind forcing increases turbulent dissipation seven times in the upper 50 m, and doubles heat fluxes at the ice-ocean interface. The presence of warm Atlantic Water close to the surface increases the temperature gradient in the water column, leading to enhanced heat flux rates within the pycnocline. Steep topography consistently enhances dissipation rates by a factor of four and episodically increases heat flux at depth. It is, however, the combination of storms and shallow Atlantic Water that leads to the highest heat flux rates observed: ice-ocean interface heat fluxes average 100 W m-2 during peak events and are associated with rapid basal sea ice melt, reaching 25 cm/d.

  2. Arctic Energy Technology Development Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Sukumar Bandopadhyay; Charles Chamberlin; Robert Chaney; Gang Chen; Godwin Chukwu; James Clough; Steve Colt; Anthony Covescek; Robert Crosby; Abhijit Dandekar; Paul Decker; Brandon Galloway; Rajive Ganguli; Catherine Hanks; Rich Haut; Kristie Hilton; Larry Hinzman; Gwen Holdman; Kristie Holland; Robert Hunter; Ron Johnson; Thomas Johnson; Doug Kame; Mikhail Kaneveskly; Tristan Kenny; Santanu Khataniar; Abhijeet Kulkami; Peter Lehman; Mary Beth Leigh; Jenn-Tai Liang; Michael Lilly; Chuen-Sen Lin; Paul Martin; Pete McGrail; Dan Miller; Debasmita Misra; Nagendra Nagabhushana; David Ogbe; Amanda Osborne; Antoinette Owen; Sharish Patil; Rocky Reifenstuhl; Doug Reynolds; Eric Robertson; Todd Schaef; Jack Schmid; Yuri Shur; Arion Tussing; Jack Walker; Katey Walter; Shannon Watson; Daniel White; Gregory White; Mark White; Richard Wies; Tom Williams; Dennis Witmer; Craig Wollard; Tao Zhu


    The Arctic Energy Technology Development Laboratory was created by the University of Alaska Fairbanks in response to a congressionally mandated funding opportunity through the U.S. Department of Energy (DOE), specifically to encourage research partnerships between the university, the Alaskan energy industry, and the DOE. The enabling legislation permitted research in a broad variety of topics particularly of interest to Alaska, including providing more efficient and economical electrical power generation in rural villages, as well as research in coal, oil, and gas. The contract was managed as a cooperative research agreement, with active project monitoring and management from the DOE. In the eight years of this partnership, approximately 30 projects were funded and completed. These projects, which were selected using an industry panel of Alaskan energy industry engineers and managers, cover a wide range of topics, such as diesel engine efficiency, fuel cells, coal combustion, methane gas hydrates, heavy oil recovery, and water issues associated with ice road construction in the oil fields of the North Slope. Each project was managed as a separate DOE contract, and the final technical report for each completed project is included with this final report. The intent of this process was to address the energy research needs of Alaska and to develop research capability at the university. As such, the intent from the beginning of this process was to encourage development of partnerships and skills that would permit a transition to direct competitive funding opportunities managed from funding sources. This project has succeeded at both the individual project level and at the institutional development level, as many of the researchers at the university are currently submitting proposals to funding agencies, with some success.

  3. The Useless Arctic: Exploiting Nature in the Arctic in the 1870s

    Directory of Open Access Journals (Sweden)

    Ulrike Spring


    Full Text Available What is the discursive genealogy of an ecological approach to the Arctic? Building on distinctions suggested by Francis Spufford and Gísli Pálsson, this article examines a specific juncture in the history of European–Arctic interaction – the reception of the Austro-Hungarian Arctic Expedition in 1874 – and traces the potential for ecological and relational understandings in what seems to be an orientalist and exploitative material. Examining the medial reception in Austria and in Norway, along with certain key texts in which Arctic wildlife is described, we find that the Norwegian reception of the expedition emphasizes practical issues connected with resource exploitation in the Arctic, while the Austrian reception mostly sees the Arctic as a symbolic resource with which to negotiate issues of identity and modernity. The Austrian discourse revolves around a set of paradoxical contradictions, the most central being those between materialism and idealism and emptiness and fullness; we argue it is the instability of such ambiguities which produces the possibility of a future ecological discourse.

  4. Prognostic, quantitative histopathologic variables in lobular carcinoma of the breast

    DEFF Research Database (Denmark)

    Ladekarl, M; Sørensen, Flemming Brandt


    of disease, vv(nuc), MI, and NI were of significant independent, prognostic value. On the basis of the multivariate analyses, a prognostic index with highly distinguishing capacity between prognostically poor and favorable cases was constructed. CONCLUSION: Quantitative histopathologic variables are of value...

  5. Evaluating biomarkers for prognostic enrichment of clinical trials. (United States)

    Kerr, Kathleen F; Roth, Jeremy; Zhu, Kehao; Thiessen-Philbrook, Heather; Meisner, Allison; Wilson, Francis Perry; Coca, Steven; Parikh, Chirag R


    A potential use of biomarkers is to assist in prognostic enrichment of clinical trials, where only patients at relatively higher risk for an outcome of interest are eligible for the trial. We investigated methods for evaluating biomarkers for prognostic enrichment. We identified five key considerations when considering a biomarker and a screening threshold for prognostic enrichment: (1) clinical trial sample size, (2) calendar time to enroll the trial, (3) total patient screening costs and the total per-patient trial costs, (4) generalizability of trial results, and (5) ethical evaluation of trial eligibility criteria. Items (1)-(3) are amenable to quantitative analysis. We developed the Biomarker Prognostic Enrichment Tool for evaluating biomarkers for prognostic enrichment at varying levels of screening stringency. We demonstrate that both modestly prognostic and strongly prognostic biomarkers can improve trial metrics using Biomarker Prognostic Enrichment Tool. Biomarker Prognostic Enrichment Tool is available as a webtool at and as a package for the R statistical computing platform. In some clinical settings, even biomarkers with modest prognostic performance can be useful for prognostic enrichment. In addition to the quantitative analysis provided by Biomarker Prognostic Enrichment Tool, investigators must consider the generalizability of trial results and evaluate the ethics of trial eligibility criteria.

  6. Prognostication in young and elderly breast cancer patients

    NARCIS (Netherlands)

    Kruijff, Esther Michelle de


    Part I describes the prognostic effect and interactions of the immune system in breast cancer patients. Part II of the thesis describes the prognostic effect of these prognostic immune parameters and biomarkers molecular subtypes and stem cell marker ALDH-1, which are known to be strong breast

  7. Decreased Prognostic Value of International Prognostic Score in Chinese Advanced Hodgkin Lymphoma Patients Treated in the Contemporary Era

    Directory of Open Access Journals (Sweden)

    Qin Wang


    Conclusions: The IPS has decreased the prognostic value in Chinese advanced HL patients treated in the contemporary era. More prognostic factors are needed to supplement this original scoring system so as to identify different risk populations more accurately.

  8. Temperature and precipitation history of the Arctic

    DEFF Research Database (Denmark)

    Miller, G. H.; Brigham-Grette, J.; Alley, R. B.


    its present extent. With the loss of land ice, sea level was about 5 m higher than present, with the extra melt coming from both Greenland and Antarctica as well as small glaciers. The Last Glacial Maximum (LGM) peaked w21 ka ago, when mean annual temperatures over parts of the Arctic were as much...

  9. Towards seasonal Arctic shipping route predictions (United States)

    Melia, N.; Haines, K.; Hawkins, E.; Day, J. J.


    The continuing decline in Arctic sea-ice will likely lead to increased human activity and opportunities for shipping in the region, suggesting that seasonal predictions of route openings will become ever more important. Here we present results from a set of ‘perfect model’ experiments to assess the predictability characteristics of the opening of Arctic sea routes. We find skilful predictions of the upcoming summer shipping season can be made from as early as January, although typically forecasts show lower skill before a May ‘predictability barrier’. We demonstrate that in forecasts started from January, predictions of route opening date are twice as uncertain as predicting the closing date and that the Arctic shipping season is becoming longer due to climate change, with later closing dates mostly responsible. We find that predictive skill is state dependent with predictions for high or low ice years exhibiting greater skill than medium ice years. Forecasting the fastest open water route through the Arctic is accurate to within 200 km when predicted from July, a six-fold increase in accuracy compared to forecasts initialised from the previous November, which are typically no better than climatology. Finally we find that initialisation of accurate summer sea-ice thickness information is crucial to obtain skilful forecasts, further motivating investment into sea-ice thickness observations, climate models, and assimilation systems.

  10. From Cold War to Arctic Battle?

    DEFF Research Database (Denmark)

    Jensen, Boris Brorman


    Greenland and the whole Arctic region is becoming a geopolitical hot spot. The opening of new potential sail routes to Asia and the possible exploitation of oil, gas and other natural resources like rare earth minerals are creating a window of opportunity for Greenland. What are the risks and who...

  11. Carbon dioxide in Arctic and subarctic regions

    Energy Technology Data Exchange (ETDEWEB)

    Gosink, T. A.; Kelley, J. J.


    A three year research project was presented that would define the role of the Arctic ocean, sea ice, tundra, taiga, high latitude ponds and lakes and polar anthropogenic activity on the carbon dioxide content of the atmosphere. Due to the large physical and geographical differences between the two polar regions, a comparison of CO/sub 2/ source and sink strengths of the two areas was proposed. Research opportunities during the first year, particularly those aboard the Swedish icebreaker, YMER, provided additional confirmatory data about the natural source and sink strengths for carbon dioxide in the Arctic regions. As a result, the hypothesis that these natural sources and sinks are strong enough to significantly affect global atmospheric carbon dioxide levels is considerably strengthened. Based on the available data we calculate that the whole Arctic region is a net annual sink for about 1.1 x 10/sup 15/ g of CO/sub 2/, or the equivalent of about 5% of the annual anthropogenic input into the atmosphere. For the second year of this research effort, research on the seasonal sources and sinks of CO/sub 2/ in the Arctic will be continued. Particular attention will be paid to the seasonal sea ice zones during the freeze and thaw periods, and the tundra-taiga regions, also during the freeze and thaw periods.

  12. Methods for shorebird surveys in the Arctic (United States)

    Jonathan Bart; Susan L. Earnst


    A substantial effort is being made to develop a longterm monitoring program for shorebirds in North American (Brown et al. 2000, Donaldson et al. 2001, Bart et al. this volume). The current program, PRISM (Program for Regional and International Shorebird Monitoring), has four segments: arctic and boreal breeding surveys, temperate breeding surveys, temperate non-...

  13. Contrasts between Antarctic and Arctic ozone depletion. (United States)

    Solomon, Susan; Portmann, Robert W; Thompson, David W J


    This work surveys the depth and character of ozone depletion in the Antarctic and Arctic using available long balloon-borne and ground-based records that cover multiple decades from ground-based sites. Such data reveal changes in the range of ozone values including the extremes observed as polar air passes over the stations. Antarctic ozone observations reveal widespread and massive local depletion in the heart of the ozone "hole" region near 18 km, frequently exceeding 90%. Although some ozone losses are apparent in the Arctic during particular years, the depth of the ozone losses in the Arctic are considerably smaller, and their occurrence is far less frequent. Many Antarctic total integrated column ozone observations in spring since approximately the 1980s show values considerably below those ever observed in earlier decades. For the Arctic, there is evidence of some spring season depletion of total ozone at particular stations, but the changes are much less pronounced compared with the range of past data. Thus, the observations demonstrate that the widespread and deep ozone depletion that characterizes the Antarctic ozone hole is a unique feature on the planet.

  14. Shallow freshwater ecosystems of the circumpolar Arctic

    DEFF Research Database (Denmark)

    Rautio, Milla; Dufresne, France; Laurion, Isabelle


    This review provides a synthesis of limnological data and conclusions from studies on ponds and small lakes at our research sites in Subarctic and Arctic Canada, Alaska, northern Scandinavia, and Greenland. Many of these water bodies contain large standing stocks of benthic microbial mats that gr...

  15. Exploring the diversity of Arctic eelpouts

    DEFF Research Database (Denmark)

    Ghigliotti, L.; Møller, Peter Rask; Cheng, C.-H. C.


    Zoarcidae (eelpouts), including 298 recognized valid species, is the most diverse family in the suborder Zoarcoidei (order Perciformes). Many of the species exhibit a great degree of phenotypic plasticity. In the present work, we analyze the genome of six Arctic species from the most diversified...

  16. The Cenozoic palaeoenvironment of the Arctic Ocean. (United States)

    Moran, Kathryn; Backman, Jan; Brinkhuis, Henk; Clemens, Steven C; Cronin, Thomas; Dickens, Gerald R; Eynaud, Frédérique; Gattacceca, Jérôme; Jakobsson, Martin; Jordan, Richard W; Kaminski, Michael; King, John; Koc, Nalan; Krylov, Alexey; Martinez, Nahysa; Matthiessen, Jens; McInroy, David; Moore, Theodore C; Onodera, Jonaotaro; O'Regan, Matthew; Pälike, Heiko; Rea, Brice; Rio, Domenico; Sakamoto, Tatsuhiko; Smith, David C; Stein, Ruediger; St John, Kristen; Suto, Itsuki; Suzuki, Noritoshi; Takahashi, Kozo; Watanabe, Mahito; Yamamoto, Masanobu; Farrell, John; Frank, Martin; Kubik, Peter; Jokat, Wilfried; Kristoffersen, Yngve


    The history of the Arctic Ocean during the Cenozoic era (0-65 million years ago) is largely unknown from direct evidence. Here we present a Cenozoic palaeoceanographic record constructed from >400 m of sediment core from a recent drilling expedition to the Lomonosov ridge in the Arctic Ocean. Our record shows a palaeoenvironmental transition from a warm 'greenhouse' world, during the late Palaeocene and early Eocene epochs, to a colder 'icehouse' world influenced by sea ice and icebergs from the middle Eocene epoch to the present. For the most recent approximately 14 Myr, we find sedimentation rates of 1-2 cm per thousand years, in stark contrast to the substantially lower rates proposed in earlier studies; this record of the Neogene reveals cooling of the Arctic that was synchronous with the expansion of Greenland ice (approximately 3.2 Myr ago) and East Antarctic ice (approximately 14 Myr ago). We find evidence for the first occurrence of ice-rafted debris in the middle Eocene epoch (approximately 45 Myr ago), some 35 Myr earlier than previously thought; fresh surface waters were present at approximately 49 Myr ago, before the onset of ice-rafted debris. Also, the temperatures of surface waters during the Palaeocene/Eocene thermal maximum (approximately 55 Myr ago) appear to have been substantially warmer than previously estimated. The revised timing of the earliest Arctic cooling events coincides with those from Antarctica, supporting arguments for bipolar symmetry in climate change.

  17. Dendro-provenancing of Arctic driftwood

    Czech Academy of Sciences Publication Activity Database

    Hellmann, L.; Tegel, W.; Geyer, J.; Kirdyanov, A. V.; Nikolaev, A. N.; Eggertsson, O.; Altman, Jan; Reinig, F.; Morganti, S.; Wacker, L.; Büntgen, Ulf


    Roč. 162, 15 April 2017 (2017), s. 1-11 ISSN 0277-3791 R&D Projects: GA ČR(CZ) GA17-07378S Institutional support: RVO:67985939 ; RVO:67179843 Keywords : Driftwood * Arctic ocean * Boreal forest Subject RIV: DG - Athmosphere Sciences, Meteorology OBOR OECD: Climatic research Impact factor: 4.797, year: 2016

  18. Conflict Resolution Practices of Arctic Aboriginal Peoples

    NARCIS (Netherlands)

    Gendron, R.; Hille, C.


    This article presents an overview of the conflict resolution practices of indigenous populations in the Arctic. Among the aboriginal groups discussed are the Inuit, the Aleut, and the Saami. Having presented the conflict resolution methods, the authors discuss the types of conflicts that are

  19. Arctic Ice Melting: National Security Implications (United States)


    be a curse rather than a good, and under no conditions can it either lead into freedom or constitute a proof for its existence. - Hannah ... Arendt 39 How will the domestic or foreign economic policies of the United States be affected by Arctic ice melting? Increased access to the

  20. Rossby Waves in the Arctic Ocean

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Schmith, Torben

    The Arctic Ocean has a characteristic stable stratification with fresh and cold water occupying the upper few hundred meters and the warm and more saline Atlantic waters underneath. These water masses are separated by the cold halocline. The stability of the cold halocline regulates the upward di...... of the thermohaline circulation....

  1. Requirements Flowdown for Prognostics and Health Management (United States)

    Goebel, Kai; Saxena, Abhinav; Roychoudhury, Indranil; Celaya, Jose R.; Saha, Bhaskar; Saha, Sankalita


    Prognostics and Health Management (PHM) principles have considerable promise to change the game of lifecycle cost of engineering systems at high safety levels by providing a reliable estimate of future system states. This estimate is a key for planning and decision making in an operational setting. While technology solutions have made considerable advances, the tie-in into the systems engineering process is lagging behind, which delays fielding of PHM-enabled systems. The derivation of specifications from high level requirements for algorithm performance to ensure quality predictions is not well developed. From an engineering perspective some key parameters driving the requirements for prognostics performance include: (1) maximum allowable Probability of Failure (PoF) of the prognostic system to bound the risk of losing an asset, (2) tolerable limits on proactive maintenance to minimize missed opportunity of asset usage, (3) lead time to specify the amount of advanced warning needed for actionable decisions, and (4) required confidence to specify when prognosis is sufficiently good to be used. This paper takes a systems engineering view towards the requirements specification process and presents a method for the flowdown process. A case study based on an electric Unmanned Aerial Vehicle (e-UAV) scenario demonstrates how top level requirements for performance, cost, and safety flow down to the health management level and specify quantitative requirements for prognostic algorithm performance.

  2. Prognostic indices in childhood heart failure

    African Journals Online (AJOL)

    mia (28%), and congenital heart disease (25 %). There was a case-fatality rate of 24% among the study population. Poor prognostic indices identified were age below one year or above 5years, presence of underlying acute respiratory in- fections, rheumatic heart disease and renal disorders. Conclusion: Heart failure in ...

  3. Identification of Prostate Cancer Prognostic Markers (United States)


    role in cellular energetics and growth. So far, our results suggest that genomic alterations may serve as prognostic markers that would improve the...shRNA vectors with better knockdown efficiency . Stable ECI1- knockdown cells would be ultimately used to perform rescue experiments for the phenotypes

  4. Prognostic factors for neckpain in general practice.

    NARCIS (Netherlands)

    Hoving, J.L.; Vet, H.C.W. de; Twisk, J.W.R.; Devillé, W.L.J.M.; Windt, D. van der; Koes, B.W.; Bouter, L.M.


    Prognostic studies on neck pain are scarce and are typically restricted to short-term follow-up only. In this prospective cohort study, indicators of short- and long-term outcomes of neck pain were identified that can easily be measured in general practice. Patients between 18 and 70 years of age,

  5. Prognostic factors in Guillain-Barre syndrome

    Directory of Open Access Journals (Sweden)

    Semra Mungan


    Full Text Available Objective: Guillain–Barre syndrome (GBS is an immune-mediated disorder of peripheral nerves resulting as acute inflammatory demyelinating polyradiculoneuropathy. GBS has a heterogeneous clinical course and laboratory findings. Acute onset and progressive course, and is usually associated with a good prognosis but some forms have a poor prognosis. Factors that can affect the prognosis of GBS have been investigated in several studies. Assessment of poor prognostic factors of GBS plays a vital role in the management and monitorization of patients. Methods: In this retrospective study of patients admitted to the acute phase of GBS removing clinical and laboratory profiles and was planned to investigate the prognostic factors. Results: Totally 23 patients (Female/male: 16/7 were recruited. Mean age was 47 (range: 17-70 years. Statistically significant poor prognostic factors were advanced age (p=0.042, erythrocyte sedimentation rate (p=0.027 and serum albumin level (p=0.007. Conclusion: Advanced age, increased ESR and decreased albumin levels were found as poor prognostic factors in GBS.

  6. Prognostic biological features in neck dissection specimens

    NARCIS (Netherlands)

    Woolgar, J.A.; Triantafyllou, A.; Lewis Jr., J.S.; Hunt, J.; Williams, M.D.; Takes, R.P.; Thompson, L.D.; Slootweg, P.J.; Devaney, K.O.; Ferlito, A.


    The superior prognostic value offered by routine histopathological staging of neck dissections, as compared to clinical staging using palpation and modern imaging techniques, is well established in the literature concerning the management of squamous cell carcinoma of the head and neck. In this

  7. Towards Performance Prognostics of a Launch Valve (United States)


    Towards Performance Prognostics of a Launch Valve Glenn Shevach1, Mark Blair2, James Hing3, Larry Venetsky4, Everard Martin5, John Wheelock6...focuses on robotics and machine learning for ALRE & SE applications. Everard Martin is a Mechanical Engineer in the Steam Catapult Launcher In-Service

  8. The biology of melanoma prognostic factors.

    NARCIS (Netherlands)

    Spatz, A.; Stock, N.; Batist, G.; Kempen, L.C.L.T. van


    Cutaneous melanoma still represents a paradox among all solid tumors. It is the cancer for which the best prognostic markers ever identified in solid tumors are available, yet there is very little understanding of their biological significance. This review focuses on recent biological data that shed

  9. Integrated Diagnostics and Prognostics of Rotating Machinery

    Directory of Open Access Journals (Sweden)

    Kam W. Ng


    Full Text Available This paper provides an overview of current research efforts in integrated diagnostics and prognostics of rotating machinery. Specifically, the following topics are discussed: sensing techniques and sensors; signal detection, identification and extraction; classification of faults; predictive failure models; data/model fusion; information management; and man–machine interface. Technical issues, recommendations, and future research directions are also addressed.

  10. Arctic Gas hydrate, Environment and Climate (United States)

    Mienert, Jurgen; Andreassen, Karin; Bünz, Stefan; Carroll, JoLynn; Ferre, Benedicte; Knies, Jochen; Panieri, Giuliana; Rasmussen, Tine; Myhre, Cathrine Lund


    Arctic methane hydrate exists on land beneath permafrost regions and offshore in shelf and continental margins sediments. Methane or gas hydrate, an ice-like substrate, consists mainly of light hydrocarbons (mostly methane from biogenic sources but also ethane and propane from thermogenic sources) entrapped by a rigid cage of water molecules. The pressure created by the overlying water and sediments offshore stabilizes the CH4 in continental margins at a temperature range well above freezing point; consequently CH4 exists as methane ice beneath the seabed. Though the accurate volume of Arctic methane hydrate and thus the methane stored in hydrates throughout the Quaternary is still unknown it must be enormous if one considers the vast regions of Arctic continental shelves and margins as well as permafrost areas offshore and on land. Today's subseabed methane hydrate reservoirs are the remnants from the last ice age and remain elusive targets for both unconventional energy and as a natural methane emitter influencing ocean environments and ecosystems. It is still contentious at what rate Arctic warming may govern hydrate melting, and whether the methane ascending from the ocean floor through the hydrosphere reaches the atmosphere. As indicated by Greenland ice core records, the atmospheric methane concentration rose rapidly from ca. 500 ppb to ca. 750 ppb over a short time period of just 150 years at the termination of the younger Dryas period ca. 11600 years ago, but the dissociation of large quantities of methane hydrates on the ocean floor have not been documented yet (Brook et al., 2014 and references within). But with the major projected warming and sea ice melting trend (Knies et al., 2014) one may ask, for how long will CH4 stay trapped in methane hydrates if surface and deep-ocean water masses will warm and permafrost continuous to melt (Portnov et al. 2014). How much of the Arctic methane will be consumed by the micro- and macrofauna, how much will

  11. Profound Impacts of AN Arctic Face Lift (United States)

    Nghiem, Son

    Son Nghiem, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, United States The ice cover on the Arctic Ocean has undergone a face lift that removes much of the older and thicker perennial ice and replaces it with the younger and thinner seasonal ice. Although the sea ice cover is a thin skin compared to the depth of the Arctic Ocean, this face lift exerts profound change in the Arctic environment. Here, we present scatterometer remote sensing of Arctic sea ice change and its implication on chemical processes from the ice surface to the troposphere extending into the internal continental land. In the context of a half century change, the extent of perennial ice declines at rate of 0.5 million km2 per decade in the 1970s-1990s while there is no discernable trend in the 1950s-1960s. Abruptly, the rate of decrease has tripled to 1.5 million km2 per decade in the 2000s. A record was set in the reduction of Arctic perennial ice extent in winter 2008. By 1 March 2008, perennial ice extent was reduced by one million km2 compared to that at the same time in 2007. On 1 May 2009, perennial ice extent was reduced to 2.1 million km2 , which is a virtual tie to 2.2 million km2 of perennial ice extent on 1 May 2008 given the uncertainty of ±0.2 million km2 . Although the extent of perennial ice extent is similar, its distribution is quite different, with a significant perennial ice pack in the Beaufort Sea in 2008, and in contrast a large expanse of perennial ice along the Transpolar Drift Stream in 2009. The continuing drastic reduction of perennial ice significantly decreases the overall surface albedo, resulting in enhanced solar heat absorption in spring and summer, which further decreases the Arctic ice pack through the ice-albedo feedback mechanism and ice melt from the underside due to oceanic thermodynamic interactions. Satellite maps of sea ice class distribution show the closely conformation with patterns of

  12. The Arctic - A New Region for China's Foreign Policy

    Directory of Open Access Journals (Sweden)

    V S Yagiya


    Full Text Available Article is devoted to foreign policy of China in the Arctic. Main attention is paid to strategic view of the China concerning the Arctic, to bilateral and multilateral cooperation on the Arctic issues, also to opinion of Russian experts about discussing of Russian-China economic partnership. It was shown interests of the People's Republic of China in the Arctic: use Arctic transport system from the Pacific Rim to Europe; possibility of access to the Arctic resources; seeks of partners for the realized of Arctic projects and programs. It was pointed six directions of China cooperation in the Arctic: a scientific researches, b natural minerals, oil and gas issues, c tourism, d routes of the Arctic navigation, e use of high technologies in development of regional economy, e cooperation in the cultural and educational spheres. Authors are summarized that at the initial stage of the international cooperation in the Arctic polar scientific researches become as the tool of “he soft power”, and in the long term - the Northern Sea Route of the Russian Federation is included in the Strategy of China Economic belt and the Maritime Silk Route in the XXI century.

  13. Radioactive contamination in Arctic - present situation and future challenges

    Energy Technology Data Exchange (ETDEWEB)

    Strand, Per [Norwegian Radiation Protection Authority, Oesteraes (Norway)


    There is currently a focus on radioactivity and the Arctic region. The reason for this is probably the high number of nuclear sources in parts of the Arctic and the vulnerability of Arctic systems to radioactive contamination. The Arctic environment is also perceived as a wilderness and the need for the protection of this wilderness against contamination is great. In the last decade information has also been released concerning the nuclear situation which has caused concern in many countries. Due to such concerns, the International Arctic Environmental Protection Strategy (IAEPS) was launched in 1991 and the Arctic Monitoring and Assessment Programme (AMAP) was established. AMAP is undertaking an assessment of the radioactive contamination of the Arctic and its radiological consequences. In 1996 IAEPS became part of the Arctic Council. AMAP presented one main report in 1997 and another in 1998. There are also several other national, bilateral and international programmes in existence which deal with this issue. This paper summarises some of current knowledge about sources of radioactive contamination, vulnerability, exposure of man, and potential sources for radioactive contamination within Arctic and some views on the future needs for work concerning radioactivity in Arctic. (au)

  14. Collaborative Research: Improving Decadal Prediction of Arctic Climate Variability and Change Using a Regional Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Gutowski, William J. [Iowa State Univ., Ames, IA (United States)


    This project developed and applied a regional Arctic System model for enhanced decadal predictions. It built on successful research by four of the current PIs with support from the DOE Climate Change Prediction Program, which has resulted in the development of a fully coupled Regional Arctic Climate Model (RACM) consisting of atmosphere, land-hydrology, ocean and sea ice components. An expanded RACM, a Regional Arctic System Model (RASM), has been set up to include ice sheets, ice caps, mountain glaciers, and dynamic vegetation to allow investigation of coupled physical processes responsible for decadal-scale climate change and variability in the Arctic. RASM can have high spatial resolution (~4-20 times higher than currently practical in global models) to advance modeling of critical processes and determine the need for their explicit representation in Global Earth System Models (GESMs). The pan-Arctic region is a key indicator of the state of global climate through polar amplification. However, a system-level understanding of critical arctic processes and feedbacks needs further development. Rapid climate change has occurred in a number of Arctic System components during the past few decades, including retreat of the perennial sea ice cover, increased surface melting of the Greenland ice sheet, acceleration and thinning of outlet glaciers, reduced snow cover, thawing permafrost, and shifts in vegetation. Such changes could have significant ramifications for global sea level, the ocean thermohaline circulation and heat budget, ecosystems, native communities, natural resource exploration, and commercial transportation. The overarching goal of the RASM project has been to advance understanding of past and present states of arctic climate and to improve seasonal to decadal predictions. To do this the project has focused on variability and long-term change of energy and freshwater flows through the arctic climate system. The three foci of this research are: - Changes

  15. The Biochemical Prognostic Factors of Subclinical Hypothyroidism

    Directory of Open Access Journals (Sweden)

    Myung Won Lee


    Full Text Available BackgroundPatients with subclinical hypothyroidism (SHT are common in clinical practice. However, the clinical significance of SHT, including prognosis, has not been established. Further clarifying SHT will be critical in devising a management plan and treatment guidelines for SHT patients. Thus, the aim of this study was to investigate the prognostic factors of SHT.MethodsWe reviewed the medical records of Korean patients who visited the endocrinology outpatient clinic of Severance Hospital from January 2008 to September 2012. Newly-diagnosed patients with SHT were selected and reviewed retrospectively. We compared two groups: the SHT maintenance group and the spontaneous improvement group.ResultsThe SHT maintenance group and the spontaneous improvement group had initial thyroid-stimulating hormone (TSH levels that were significantly different (P=0.035. In subanalysis for subjects with TSH levels between 5 to 10 µIU/mL, the spontaneous improvement group showed significantly lower antithyroid peroxidase antibody (anti-TPO-Ab titer than the SHT maintenance group (P=0.039. Regarding lipid profiles, only triglyceride level, unlike total cholesterol and low density lipoprotein cholesterol, was related to TSH level, which is correlated with the severity of SHT. Diffuse thyroiditis on ultrasonography only contributed to the severity of SHT, not to the prognosis. High sensitivity C-reactive protein and urine iodine excretion, generally regarded as possible prognostic factors, did not show any significant relation with the prognosis and severity of SHT.ConclusionOnly initial TSH level was a definite prognostic factor of SHT. TPO-Ab titer was also a helpful prognostic factor for SHT in cases with mildly elevated TSH. Other than TSH and TPO-Ab, we were unable to validate biochemical prognostic factors in this retrospective study for Korean SHT patients.

  16. Modeling the summertime Arctic cloudy boundary layer

    Energy Technology Data Exchange (ETDEWEB)

    Curry, J.A.; Pinto, J.O. [Univ. of Colorado, Boulder, CO (United States); McInnes, K.L. [CSIRO Division of Atmospheric Research, Mordialloc (Australia)


    Global climate models have particular difficulty in simulating the low-level clouds during the Arctic summer. Model problems are exacerbated in the polar regions by the complicated vertical structure of the Arctic boundary layer. The presence of multiple cloud layers, a humidity inversion above cloud top, and vertical fluxes in the cloud that are decoupled from the surface fluxes, identified in Curry et al. (1988), suggest that models containing sophisticated physical parameterizations would be required to accurately model this region. Accurate modeling of the vertical structure of multiple cloud layers in climate models is important for determination of the surface radiative fluxes. This study focuses on the problem of modeling the layered structure of the Arctic summertime boundary-layer clouds and in particular, the representation of the more complex boundary layer type consisting of a stable foggy surface layer surmounted by a cloud-topped mixed layer. A hierarchical modeling/diagnosis approach is used. A case study from the summertime Arctic Stratus Experiment is examined. A high-resolution, one-dimensional model of turbulence and radiation is tested against the observations and is then used in sensitivity studies to infer the optimal conditions for maintaining two separate layers in the Arctic summertime boundary layer. A three-dimensional mesoscale atmospheric model is then used to simulate the interaction of this cloud deck with the large-scale atmospheric dynamics. An assessment of the improvements needed to the parameterizations of the boundary layer, cloud microphysics, and radiation in the 3-D model is made.

  17. Arctic and Antarctic sea ice and climate (United States)

    Barreira, S.


    Principal Components Analysis in T-Mode Varimax rotated was performed on Antarctic and Arctic monthly sea ice concentration anomalies (SICA) fields for the period 1979-2014, in order to investigate which are the main spatial characteristics of sea ice and its relationship with atmospheric circulation. This analysis provides 5 patterns of sea ice for inter-spring period and 3 patterns for summer-autumn for Antarctica (69,2% of the total variance) and 3 different patterns for summer-autumn and 3 for winter-spring season for the Arctic Ocean (67,8% of the total variance).Each of these patterns has a positive and negative phase. We used the Monthly Polar Gridded Sea Ice Concentrations database derived from satellite information generated by NASA Team algorithm. To understand the links between the SICA and climate trends, we extracted the mean pressure and, temperature field patterns for the months with high loadings (positive or negative) of the sea ice patterns that gave distinct atmospheric structures associated with each one. For Antarctica, the first SICA spatial winter-spring pattern in positive phase shows a negative SICA centre over the Drake Passage and north region of Bellingshausen and Weddell Seas together with another negative SICA centre over the East Indian Ocean. Strong positive centres over the rest of the Atlantic and Indian Oceans basins and the Amundsen Sea are also presented. A strong negative pressure anomaly covers most of the Antarctic Continent centered over the Bellingshausen Sea accompanied by three positive pressure anomalies in middle-latitudes. During recent years, the Arctic showed persistent associations of sea-ice and climate patterns principally during summer. Our strongest summer-autumn pattern in negative phase showed a marked reduction on SICA over western Arctic, primarily linked to an overall increase in Arctic atmospheric temperature most pronounced over the Beaufort, Chukchi and East Siberian Seas, and a positive anomaly of

  18. Sulfate Aerosol in the Arctic: Source Attribution and Radiative Forcing

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yang [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland WA USA; Wang, Hailong [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland WA USA; Smith, Steven J. [Joint Global Change Research Institute, Pacific Northwest National Laboratory, College Park MD USA; Easter, Richard C. [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland WA USA; Rasch, Philip J. [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland WA USA


    Source attributions of Arctic sulfate and its direct radiative effect for 2010–2014 are quantified in this study using the Community Earth System Model (CESM) equipped with an explicit sulfur source-tagging technique. Regions that have high emissions and/or are near/within the Arctic present relatively large contributions to Arctic sulfate burden, with the largest contribution from sources in East Asia (27%). East Asia and South Asia together have the largest contributions to Arctic sulfate concentrations at 9–12 km, whereas sources within or near the Arctic account largely below 2 km. For remote sources with strong emissions, their contributions to Arctic sulfate burden are primarily driven by meteorology, while contributions of sources within or near the Arctic are dominated by their emission strength. The sulfate direct radiative effect (DRE) is –0.080 W m-2 at the Arctic surface, offsetting the net warming effect from the combination of in-snow heating and DRE cooling from black carbon. East Asia, Arctic local and Russia/Belarus/Ukraine sources contribute –0.017, –0.016 and –0.014 W m-2, respectively, to Arctic sulfate DRE. A 20% reduction in anthropogenic SO2 emissions leads to a net increase of +0.013 W m-2 forcing at the Arctic surface. These results indicate that a joint reduction in BC emissions could prevent possible Arctic warming from future reductions in SO2 emissions. Sulfate DRE efficiency calculations suggest that short transport pathways together with meteorology favoring long sulfate lifetimes make certain sources more efficient in influencing the Arctic sulfate DRE.

  19. Pan-Arctic observations in GRENE Arctic Climate Change Research Project and its successor (United States)

    Yamanouchi, Takashi


    We started a Japanese initiative - "Arctic Climate Change Research Project" - within the framework of the Green Network of Excellence (GRENE) Program, funded by the Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT), in 2011. This Project targeted understanding and forecasting "Rapid Change of the Arctic Climate System and its Global Influences." Four strategic research targets are set by the Ministry: 1. Understanding the mechanism of warming amplification in the Arctic; 2. Understanding the Arctic climate system for global climate and future change; 3. Evaluation of the impacts of Arctic change on the weather and climate in Japan, marine ecosystems and fisheries; 4. Projection of sea ice distribution and Arctic sea routes. Through a network of universities and institutions in Japan, this 5-year Project involves more than 300 scientists from 39 institutions and universities. The National Institute of Polar Research (NIPR) works as the core institute and The Japan Agency for Marine- Earth Science and Technology (JAMSTEC) joins as the supporting institute. There are 7 bottom up research themes approved: the atmosphere, terrestrial ecosystems, cryosphere, greenhouse gases, marine ecology and fisheries, sea ice and Arctic sea routes and climate modeling, among 22 applications. The Project will realize multi-disciplinal study of the Arctic region and connect to the projection of future Arctic and global climatic change by modeling. The project has been running since the beginning of 2011 and in those 5 years pan-Arctic observations have been carried out in many locations, such as Svalbard, Russian Siberia, Alaska, Canada, Greenland and the Arctic Ocean. In particular, 95 GHz cloud profiling radar in high precision was established at Ny-Ålesund, Svalbard, and intensive atmospheric observations were carried out in 2014 and 2015. In addition, the Arctic Ocean cruises by R/V "Mirai" (belonging to JAMSTEC) and other icebreakers belonging to other

  20. Ozone variability and halogen oxidation within the Arctic and sub-Arctic springtime boundary layer

    Directory of Open Access Journals (Sweden)

    J. B. Gilman


    Full Text Available The influence of halogen oxidation on the variabilities of ozone (O3 and volatile organic compounds (VOCs within the Arctic and sub-Arctic atmospheric boundary layer was investigated using field measurements from multiple campaigns conducted in March and April 2008 as part of the POLARCAT project. For the ship-based measurements, a high degree of correlation (r = 0.98 for 544 data points collected north of 68° N was observed between the acetylene to benzene ratio, used as a marker for chlorine and bromine oxidation, and O3 signifying the vast influence of halogen oxidation throughout the ice-free regions of the North Atlantic. Concurrent airborne and ground-based measurements in the Alaskan Arctic substantiated this correlation and were used to demonstrate that halogen oxidation influenced O3 variability throughout the Arctic boundary layer during these springtime studies. Measurements aboard the R/V Knorr in the North Atlantic and Arctic Oceans provided a unique view of the transport of O3-poor air masses from the Arctic Basin to latitudes as far south as 52° N. FLEXPART, a Lagrangian transport model, was used to quantitatively determine the exposure of air masses encountered by the ship to first-year ice (FYI, multi-year ice (MYI, and total ICE (FYI+MYI. O3 anti-correlated with the modeled total ICE tracer (r = −0.86 indicating that up to 73% of the O3 variability measured in the Arctic marine boundary layer could be related to sea ice exposure.

  1. Distributed Prognostic Health Management with Gaussian Process Regression (United States)

    Saha, Sankalita; Saha, Bhaskar; Saxena, Abhinav; Goebel, Kai Frank


    Distributed prognostics architecture design is an enabling step for efficient implementation of health management systems. A major challenge encountered in such design is formulation of optimal distributed prognostics algorithms. In this paper. we present a distributed GPR based prognostics algorithm whose target platform is a wireless sensor network. In addition to challenges encountered in a distributed implementation, a wireless network poses constraints on communication patterns, thereby making the problem more challenging. The prognostics application that was used to demonstrate our new algorithms is battery prognostics. In order to present trade-offs within different prognostic approaches, we present comparison with the distributed implementation of a particle filter based prognostics for the same battery data.

  2. Lean construction as an effective organization model in Arctic

    Directory of Open Access Journals (Sweden)

    Balashova Elena S.


    Full Text Available In recent time, due to the sharp climatic changes, the Arctic attracts an increased interest of the world powers as a strategically important object. In 2013, the development strategy of the Arctic zone of the Russian Federation and national security for the period up to 2020 was approved by the President. In this strategy, the socio-economic development of the region in terms of improving the quality of life, expressed in the implementation of housing and civil engineering is very important. The goal of the study is to identify effective organization model of construction in the Arctic zone of the Russian Federation. Lean construction as a dynamically developing methodology abroad is analyzed. Characteristics of this organization model of construction meet the necessary requirements for the construction of various infrastructure objects in the Arctic. Therefore, the concept of lean construction can be an effective strategy of development of the Arctic regions of Russia as well as other Arctic countries.

  3. CARVE: The Carbon in Arctic Reservoirs Vulnerability Experiment (United States)

    Miller, Charles E.; Dinardo, Steven J.


    The Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) is a NASA Earth Ventures (EV-1) investigation designed to quantify correlations between atmospheric and surface state variables for the Alaskan terrestrial ecosystems through intensive seasonal aircraft campaigns, ground-based observations, and analysis sustained over a 5-year mission. CARVE bridges critical gaps in our knowledge and understanding of Arctic ecosystems, linkages between the Arctic hydrologic and terrestrial carbon cycles, and the feedbacks from fires and thawing permafrost. CARVE's objectives are to: (1) Directly test hypotheses attributing the mobilization of vulnerable Arctic carbon reservoirs to climate warming; (2) Deliver the first direct measurements and detailed maps of CO2 and CH4 sources on regional scales in the Alaskan Arctic; and (3) Demonstrate new remote sensing and modeling capabilities to quantify feedbacks between carbon fluxes and carbon cycle-climate processes in the Arctic (Figure 1). We describe the investigation design and results from 2011 test flights in Alaska.

  4. The Future of the Arctic: A Key to Global Sustainability

    Directory of Open Access Journals (Sweden)

    Francesco Stipo


    Full Text Available The USACOR Report forecasts that by 2050 the Arctic will become the major supplier of energy to the world, in particular oil and natural gas, and natural resources such as mineral water. In the coming decades, the population in the Arctic region is projected to increase significantly due to the expansion of exploration for resources. The Report recommends that a Zero emission policy be implemented throughout the Arctic area for water emissions into the seas, rivers, or estuaries and oceans. The Report recommends that the Arctic Council guarantees safe navigation and environmental protection, establishing a Fund to cover expenses to purchase icebreakers and towards the cost of the personnel in order to assist commercial navigation in the Arctic region. The Arctic Council shall also issue environmental rules to regulate the mineral exploitation in the region and ensure that the wildlife is protected and that the exploitation of resources is conducted in a sustainable manner.

  5. Molecular epidemiological study of Arctic rabies virus isolates from Greenland and comparison with isolates from throughout the Arctic and Baltic regions

    DEFF Research Database (Denmark)

    Mansfield, K.L.; Racloz, V.; McElhinney, L.M.


    We report a Molecular epidemiological study of rabies in Arctic Countries by comparing a panel of novel Greenland isolates to a larger cohort of viral sequences from both Arctic and Baltic regions. Rabies Virus isolates originating from wildlife (Arctic/red foxes, raccoon-dogs and reindeer), from...... sequences from the Arctic and Arctic-like viruses, which were distinct from rabies isolates originating ill the Baltic region of Europe, the Steppes in Russia and from North America. The Arctic-like group consist of isolates from India, Pakistan, southeast Siberia and Japan. The Arctic group...... in northeast Siberia and Alaska. Arctic 2b isolates represent a biotype, which is dispersed throughout the Arctic region. The broad distribution of rabies in the Arctic regions including Greenland, Canada and Alaska provides evidence for the movement of rabies across borders....

  6. Fundamental differences between Arctic and Antarctic ozone depletion


    Solomon, Susan; Haskins, Jessica; Ivy, Diane J.; Min, Flora


    Fundamental differences in observed ozone depletion between the Arctic and the Antarctic are shown, clarifying distinctions between both average and extreme ozone decreases in the two hemispheres. Balloon-borne and satellite measurements in the heart of the ozone layer near 18−24 km altitude show that extreme ozone decreases often observed in the Antarctic ozone hole region have not yet been measured in the Arctic in any year, including the unusually cold Arctic spring of 2011. The data provi...

  7. Arctic Sovereignty Disputes: International Relations Theory in the High North (United States)


    Fleet since the end of the Cold War, Moscow continues to regard Murmansk , the Barents Sea and adjacent Arctic waters as vital to the defense of...end of the Cold War, Moscow continues to regard Murmansk , the Barents Sea and adjacent Arctic waters as vital to the defense of Russia and the...minimum, and several ships transited the northern sea route to from Murmansk to the far East. The future of the Arctic is here, now

  8. National security of Russia in the Arctic: Problems and solutions

    Directory of Open Access Journals (Sweden)

    Ivanov G. V.


    Full Text Available The paper contains the analysis of actual problems of national security of Russia in the Arctic. The author has come to the conclusion that the threats of military security of the Russian Federation in the Arctic region are of rising character and the development of modern military-political situation suggests that large-scale use of military forces in the Arctic zone is unlikely and possible resolution of conflicts lies in the international legal area

  9. Indian scientific endeavors in Ny-Ålesund, Arctic

    Directory of Open Access Journals (Sweden)

    Neloy Khare


    Full Text Available An ice free Arctic can effect tropical climate and is therefore a key variable to understand the climate change. In order to undertake studies in the Arctic region, on 1st July 2008, the Indian station ‘Himadri’ has been opened in Ny-Ålesund. With India, 15 stations from 10 countries are now established in Ny-Ålesund. This report highlights Indian initiatives in the Arctic region.

  10. Letter. Late cretaceous seasonal ocean variability from the arctic


    Davies, Andrew; Kemp, Alan E.S.; Pike, Jennifer


    The modern Arctic Ocean is regarded as barometer of global change and amplifier of global warming1 and therefore records of past Arctic change are of a premium for palaeoclimate reconstruction. Little is known of the state of the Arctic Ocean in the greenhouse period of the late Cretaceous, yet records from such times may yield important clues to its future behaviour given current global warming trends. Here we present the first seasonally resolved sedimentary record from the Cretaceous from ...

  11. Features of integrative process in formation of the Arctic region


    Nadezhda Kharlampeva


    Features of integrative process in formation of the Arctic region Nadezhda Kharlampieva, Saint-Petersburg State University Article is devoted to the Arctic - the new region of contemporary international relations system where global issues of world politics are solved. Discussion around the Arctic in the early 21st century can be characterized within four policy-academic thesis formulated by contemporary development and 'open region' concepts. From the view point of world political analysis, ...

  12. Arctic “ozone hole” in a cold volcanic stratosphere


    Tabazadeh, A.; Drdla, K.; M. R. Schoeberl; Hamill, P.; Toon, O. B.


    Optical depth records indicate that volcanic aerosols from major eruptions often produce clouds that have greater surface area than typical Arctic polar stratospheric clouds (PSCs). A trajectory cloud–chemistry model is used to study how volcanic aerosols could affect springtime Arctic ozone loss processes, such as chlorine activation and denitrification, in a cold winter within the current range of natural variability. Several studies indicate that severe denitrification can increase Arctic ...

  13. The Reemergence of the Arctic as a Strategic Location (United States)


    ocean filled with natural resources and encircled by some of the world’s most highly developed cultures .3 Until the summer of 2007, the Arctic did...Natural Wildlife Refuge (ANWR). Additionally, indigenous groups began to network and form regional groups to protect their culture and lifestyle.22...Arctic Council and the Barents Euro-Arctic Council [depicted in yellow]; international non-governmental organizations, such as the Inuit Circumpolar

  14. Simulation of Extreme Arctic Cyclones in IPCC AR5 Experiments (United States)


    Final Technical Report: "Simulation of Extreme Arctic Cyclones in IPCC AR5 Experiments" PI: Stephen Vavrus Nelson Institute Center for Climatic...June 2012: "Simulation of extreme Arctic cyclones in IPCC AR5 experiments", Breckenridge, CO. Oral presentation at the AGU Fall Meeting, December 2012...34Simulation of extreme Arctic cyclones in IPCC AR5 experiments", San Francisco, CA. Poster presentation at the World Climate Research Program (WCRP

  15. Selling Energy to China: Chinese Energy Politics in the Arctic


    Nguyen, Ly Kieu Le


    Abstract Until recently, the Arctic including the Arctic Ocean was only mentioned in the context of global warming. However, global warming has led to a thawing of ice that unveiled great findings of natural resources. The Arctic is now in the middle of a rapid environmental, geopolitical and economic transformation. The planting of the Russian flag by Russian researchers in 2007 on the bottom of the Artic Ocean triggered an overwhelming attention from other actors and states outside the regi...

  16. Changes in the Arctic: Background and Issues for Congress (United States)


    have potential consequences for weather in the United States, access to mineral and biological resources in the Arctic, the economies and cultures of... cultures of Arctic indigenous peoples. Two of the Coast Guard’s three polar icebreakers—Polar Star and Polar Sea—have exceeded their intended 30-year...Finland, Sweden, and Iceland . 2 These eight countries are often referred to as the Arctic 1 Except

  17. Spatial distribution of aquatic marine fungi across the western Arctic and sub-arctic. (United States)

    Hassett, Brandon T; Ducluzeau, Anne-Lise L; Collins, Roy E; Gradinger, Rolf


    Fungi are important parasites of primary producers and nutrient cyclers in aquatic ecosystems. In the Pacific-Arctic domain, fungal parasitism is linked to light intensities and algal stress that can elevate disease incidence on algae and reduce diatom concentrations. Fungi are vastly understudied in the marine realm and knowledge of their function is constrained by the current understanding of fungal distribution and drivers on global scales. To investigate the spatial distribution of fungi in the western Arctic and sub-Arctic, we used high throughput methods to sequence 18S rRNA, cloned and sequenced 28S rRNA and microscopically counted chytrid-infected diatoms. We identified a broad distribution of fungal taxa predominated by Chytridiomycota and Dikarya. Phylogenetic analysis of our Chytridiomycota clones placed Arctic marine fungi sister to the order Lobulomycetales. This clade of fungi predominated in fungal communities under ice with low snowpack. Microscopic examination of fixed seawater and sea ice samples revealed chytrids parasitizing diatoms collected across the Arctic that notably infected 25% of a single diatom species in the Bering Sea. The Pezizomycotina comprised > 95% of eukaryotic sequence reads in Greenland, providing preliminary evidence for osmotrophs being a substitute for algae as the base of food webs. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  18. Spatial Distribution of Methanesulphonic Acid in the Arctic Aerosol Collected during the Chinese Arctic Research Expedition

    Directory of Open Access Journals (Sweden)

    Peipei Ye


    Full Text Available Methanesulphonic acid (MSA, mainly derived from marine biogenic emissions has been frequently used to estimate the marine biogenic contribution. However, there are few reports on MSA over the Arctic Ocean, especially the central Arctic Ocean. Here, we analyzed MSA in aerosol samples collected over the ocean and seas during the Chinese Arctic Research Expedition (CHINARE 2012 using ion chromatography. The aerosol MSA concentrations over the Arctic Ocean varied considerably and ranged from non-detectable (ND to 229 ng/m3, with an average of 27 ± 54 ng/m3 (median: 10 ng/m3. We found the distribution of aerosol MSA exhibited an obvious regional variation, which was affected by biotic and abiotic factors. High values were generally observed in the Norwegian Sea; this phenomenon was attributed to high rates of phytoplankton primary productivity and dimethylsulfide (DMS fluxes in this region. Concentrations over the pack ice region in the central Arctic Ocean were generally lower than over the open waters at the ice edge in the Chukchi Sea. This difference was the mainly caused by sea ice. In addition, we found that higher MSA concentrations were associated with warmer sea surface temperature (SST.

  19. Arctic Research of the United States, Spring 1990, volume 4 (United States)

    Brown, Jerry; Bowen, Stephen

    This is a journal for national and international audiences of government officials, scientists, engineers, educators, Arctic residents, and other people interested in Arctic-related topics. Reports cover a broad spectrum of life in the Arctic including such topics as fish, game, health, social services, science, engineering, environment, oceanography, international activities, international cooperation, global change, conferences, polar libraries, data, policies, research, and history. The emphasis in this issue is on the importance of the Arctic Ocean and its marginal seas to U.S. national interests, including fisheries, the oil and gas industries, and global climate change processes.

  20. Behavioral interactions of penned red and arctic foxes (United States)

    Rudzinski, D.R.; Graves, H.B.; Sargeant, A.B.; Storm, G.L.


    Expansion of the geographical distribution of red foxes (Vulpes vulpes) into the far north tundra region may lead to competition between arctic (Alopex lagopus) and red foxes for space and resources. Behavioral interactions between red and arctic foxes were evaluated during 9 trials conducted in a 4.05-ha enclosure near Woodworth, North Dakota. Each trial consisted of introducing a male-female pair of arctic foxes into the enclosure and allowing them to acclimate for approximately a week before releasing a female red fox into the enclosure, followed by her mate a few days later. In 8 of 9 trials, red foxes were dominant over arctic foxes during encounters. Activity of the arctic foxes decreased upon addition of red foxes. Arctic foxes tried unsuccessfully to defend preferred den, resting, and feeding areas. Even though the outcome of competition between red and arctic foxes in the Arctic is uncertain, the more aggressive red fox can dominate arctic foxes in direct competition for den sites and other limited resources.

  1. Ocean currents shape the microbiome of Arctic marine sediments

    National Research Council Canada - National Science Library

    Hamdan, Leila J; Coffin, Richard B; Sikaroodi, Masoumeh; Greinert, Jens; Treude, Tina; Gillevet, Patrick M


    ...). Water and sediment directly underlying water with origin in the Arctic, Pacific or Atlantic oceans were analyzed by pyrosequencing and length heterogeneity-PCR in conjunction with physicochemical...

  2. PMEL EcoFOCI Early Arctic Data, 1986-1991 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pacific Marine Environmental Laboratory (PMEL) Fisheries-Oceanography Cooperative Investigations (FOCI) Early Arctic Data, 1987 - 1991

  3. Public Opinion on Canadian Arctic Sovereignty and Security

    National Research Council Canada - National Science Library

    Mathieu Landriault


    .... An examination of 18 opinion polls conducted between 2006 and 2015 that questioned respondents directly or indirectly on circumpolar affairs concluded that Canadians do not prioritize the Arctic...

  4. Arctic air pollution: Challenges and opportunities for the next decade

    Directory of Open Access Journals (Sweden)

    S.R. Arnold


    Full Text Available Abstract 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.

  5. Migration and breeding biology of Arctic terns in Greenland

    DEFF Research Database (Denmark)

    Egevang, Carsten

    (Sandøen) in high-Arctic Northeast Greenland. The level of knowledge of the Arctic tern in Greenland before 2002 was to a large extent poor, with aspects of its biology being completely unknown in the Greenland population. This thesis presents novel findings for the Arctic tern, both on an international...... scale and on a national scale. The study on Arctic tern migration (Manus I) – the longest annual migration ever recorded in any animal – is a study with an international appeal. The study documented how Greenland and Iceland breeding terns conduct the roundtrip migration to the Weddell Sea in Antarctica...

  6. Identifying Priorities for International Arctic Research and Policy (United States)

    Rachold, V.; Hik, D.; Barr, S.


    The International Arctic Science Committee (IASC) is a non-governmental, international scientific organization, founded in 1990 by representatives of national scientific organizations of the eight Arctic countries - Canada, Denmark, Finland, Iceland, Norway, Russia (at that time Union of Soviet Socialist Republics), Sweden and the United States of America. Over the past 25 years, IASC has evolved into the leading international science organization of the North and its membership today includes 23 countries involved in all aspects of Arctic research, including 15 non-Arctic countries (Austria, China, the Czech Republic, France, Germany, India, Italy, Japan, the Netherlands, Poland, Portugal, South Korea, Spain, Switzerland and the UK). The Founding Articles committed IASC to pursue a mission of encouraging and facilitating cooperation in all aspects of Arctic research, in all countries engaged in Arctic research and in all areas of the Arctic region. IASC promotes and supports leading-edge multi-disciplinary research in order to foster a greater scientific understanding of the Arctic region and its role in the Earth system. IASC has organized three forward-looking conferences focused on international and interdisciplinary perspectives for advancing Arctic research cooperation and applications of Arctic knowledge. Indeed, the IASC Founding Articles call for IASC to host these conferences periodically in order to "review the status of Arctic science, provide scientific and technical advice, and promote cooperation and links with other national and international organizations." Through its members, including national science organizations and funding agencies from all countries engaged in Arctic research, IASC is uniquely placed to undertake this task. As an accredited observer on the Arctic Council, IASC is also in the position to introduce the outcome of its science planning efforts into the Arctićs main political body and to liaise with the Arctic Council Permanent

  7. [Horse, cow and reindeer were converted into arctic domestic animals]. (United States)

    Kantanen, Juha


    Domestic animal production in the arctic region is often thought to be based exclusively on reindeer herding. There are, however, regions in Northern Europe and Siberia having a long tradition in rearing breeds of cattle and horse adapted to the northers conditions also. The development of these arctic animal breeds has been largely founded on old tradition rather than on the programs of breeding organizations. As a result of the selection carried out by nature and man, the domestic animals of arctic regions express characteristics that are metabolic, structural, associated with reproductive physiology and conducive to the adaptation to arctic conditions.

  8. The Reemergence of the Arctic as a Strategic Location

    National Research Council Canada - National Science Library

    Knell, Niave F


    ...), the European Union (EU), multinational oil and gas corporations, supra-national nongovernmental organizations, indigenous groups, the World Trade Organization, the internet, and trade among the Arctic states...

  9. Assessing calibration of prognostic risk scores. (United States)

    Crowson, Cynthia S; Atkinson, Elizabeth J; Therneau, Terry M


    Current methods used to assess calibration are limited, particularly in the assessment of prognostic models. Methods for testing and visualizing calibration (e.g. the Hosmer-Lemeshow test and calibration slope) have been well thought out in the binary regression setting. However, extension of these methods to Cox models is less well known and could be improved. We describe a model-based framework for the assessment of calibration in the binary setting that provides natural extensions to the survival data setting. We show that Poisson regression models can be used to easily assess calibration in prognostic models. In addition, we show that a calibration test suggested for use in survival data has poor performance. Finally, we apply these methods to the problem of external validation of a risk score developed for the general population when assessed in a special patient population (i.e. patients with particular comorbidities, such as rheumatoid arthritis). © The Author(s) 2013.

  10. [Prognostic factors of early breast cancer]. (United States)

    Almagro, Elena; González, Cynthia S; Espinosa, Enrique


    Decision about the administration of adjuvant therapy for early breast cancer depends on the evaluation of prognostic factors. Lymph node status, tumor size and grade of differentiation are classical variables in this regard, and can be complemented by hormonal receptor status and HER2 expression. These factors can be combined into prognostic indexes to better estimate the risk of relapse or death. Other factors are less important. Gene profiles have emerged in recent years to identify low-risk patients who can forgo adjuvant chemotherapy. A number of profiles are available and can be used in selected cases. In the future, gene profiling will be used to select patients for treatment with new targeted therapies. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

  11. Diagnostic and prognostic epigenetic biomarkers in cancer. (United States)

    Costa-Pinheiro, Pedro; Montezuma, Diana; Henrique, Rui; Jerónimo, Carmen


    Growing cancer incidence and mortality worldwide demands development of accurate biomarkers to perfect detection, diagnosis, prognostication and monitoring. Urologic (prostate, bladder, kidney), lung, breast and colorectal cancers are the most common and despite major advances in their characterization, this has seldom translated into biomarkers amenable for clinical practice. Epigenetic alterations are innovative cancer biomarkers owing to stability, frequency, reversibility and accessibility in body fluids, entailing great potential of assay development to assist in patient management. Several studies identified putative epigenetic cancer biomarkers, some of which have been commercialized. However, large multicenter validation studies are required to foster translation to the clinics. Herein we review the most promising epigenetic detection, diagnostic, prognostic and predictive biomarkers for the most common cancers.

  12. Vehicle Integrated Prognostic Reasoner (VIPR) Final Report (United States)

    Bharadwaj, Raj; Mylaraswamy, Dinkar; Cornhill, Dennis; Biswas, Gautam; Koutsoukos, Xenofon; Mack, Daniel


    A systems view is necessary to detect, diagnose, predict, and mitigate adverse events during the flight of an aircraft. While most aircraft subsystems look for simple threshold exceedances and report them to a central maintenance computer, the vehicle integrated prognostic reasoner (VIPR) proactively generates evidence and takes an active role in aircraft-level health assessment. Establishing the technical feasibility and a design trade-space for this next-generation vehicle-level reasoning system (VLRS) is the focus of our work.

  13. Prognostic Analysis of the Tactical Quiet Generator

    Energy Technology Data Exchange (ETDEWEB)

    Hively, Lee M [ORNL


    The U.S. Army needs prognostic analysis of mission-critical equipment to enable condition-based maintenance before failure. ORNL has developed and patented prognostic technology that quantifies condition change from noisy, multi-channel, time-serial data. This report describes an initial application of ORNL's prognostic technology to the Army's Tactical Quiet Generator (TQG), which is designed to operate continuously at 10 kW. Less-than-full power operation causes unburned fuel to accumulate on internal components, thereby degrading operation and eventually leading to failure. The first objective of this work was identification of easily-acquired, process-indicative data. Two types of appropriate data were identified, namely output-electrical current and voltage, plus tri-axial acceleration (vibration). The second objective of this work was data quality analysis to avoid the garbage-in-garbage-out syndrome. Quality analysis identified more than 10% of the current data as having consecutive values that are constant, or that saturate at an extreme value. Consequently, the electrical data were not analyzed further. The third objective was condition-change analysis to indicate operational stress under non-ideal operation and machine degradation in proportion to the operational stress. Application of ORNL's novel phase-space dissimilarity measures to the vibration power quantified the rising operational stress in direct proportion to the less-than-full-load power. We conclude that ORNL's technology is an excellent candidate to meet the U.S. Army's need for equipment prognostication.

  14. Machinery prognostics and prognosis oriented maintenance management

    CERN Document Server

    Yan, Jihong


    This book gives a complete presentatin of the basic essentials of machinery prognostics and prognosis oriented maintenance management, and takes a look at the cutting-edge discipline of intelligent failure prognosis technologies for condition-based maintenance.  Latest research results and application methods are introduced for signal processing, reliability moelling, deterioration evaluation, residual life prediction and maintenance-optimization as well as applications of these methods.

  15. Prognostic factors in young ovarian cancer patients

    DEFF Research Database (Denmark)

    Klar, M; Hasenburg, A; Hasanov, M


    OBJECTIVES: We evaluated in a large study meta-database of prospectively randomised phase III trials the prognostic factors for progression-free survival (PFS) and overall survival (OS) in patients 40 years of age with advanced epithelial ovarian cancer. METHODS: A total of 5055 patients...... epithelial ovarian cancer, excellent performance status, who had received complete macroscopic upfront cytoreduction and ≥5 chemotherapy cycles. RESULTS: For patients

  16. No prognostic value added by vitamin D pathway SNPs to current prognostic system for melanoma survival. (United States)

    Luo, Li; Orlow, Irene; Kanetsky, Peter A; Thomas, Nancy E; Fang, Shenying; Lee, Jeffrey E; Berwick, Marianne; Lee, Ji-Hyun


    The prognostic improvement attributed to genetic markers over current prognostic system has not been well studied for melanoma. The goal of this study is to evaluate the added prognostic value of Vitamin D Pathway (VitD) SNPs to currently known clinical and demographic factors such as age, sex, Breslow thickness, mitosis and ulceration (CDF). We utilized two large independent well-characterized melanoma studies: the Genes, Environment, and Melanoma (GEM) and MD Anderson studies, and performed variable selection of VitD pathway SNPs and CDF using Random Survival Forest (RSF) method in addition to Cox proportional hazards models. The Harrell's C-index was used to compare the performance of model predictability. The population-based GEM study enrolled 3,578 incident cases of cutaneous melanoma (CM), and the hospital-based MD Anderson study consisted of 1,804 CM patients. Including both VitD SNPs and CDF yielded C-index of 0.85, which provided slight but not significant improvement by CDF alone (C-index = 0.83) in the GEM study. Similar results were observed in the independent MD Anderson study (C-index = 0.84 and 0.83, respectively). The Cox model identified no significant associations after adjusting for multiplicity. Our results do not support clinically significant prognostic improvements attributable to VitD pathway SNPs over current prognostic system for melanoma survival.

  17. No prognostic value added by vitamin D pathway SNPs to current prognostic system for melanoma survival.

    Directory of Open Access Journals (Sweden)

    Li Luo

    Full Text Available The prognostic improvement attributed to genetic markers over current prognostic system has not been well studied for melanoma. The goal of this study is to evaluate the added prognostic value of Vitamin D Pathway (VitD SNPs to currently known clinical and demographic factors such as age, sex, Breslow thickness, mitosis and ulceration (CDF. We utilized two large independent well-characterized melanoma studies: the Genes, Environment, and Melanoma (GEM and MD Anderson studies, and performed variable selection of VitD pathway SNPs and CDF using Random Survival Forest (RSF method in addition to Cox proportional hazards models. The Harrell's C-index was used to compare the performance of model predictability. The population-based GEM study enrolled 3,578 incident cases of cutaneous melanoma (CM, and the hospital-based MD Anderson study consisted of 1,804 CM patients. Including both VitD SNPs and CDF yielded C-index of 0.85, which provided slight but not significant improvement by CDF alone (C-index = 0.83 in the GEM study. Similar results were observed in the independent MD Anderson study (C-index = 0.84 and 0.83, respectively. The Cox model identified no significant associations after adjusting for multiplicity. Our results do not support clinically significant prognostic improvements attributable to VitD pathway SNPs over current prognostic system for melanoma survival.

  18. Microbial Biogeography of the Arctic Cryosphere

    DEFF Research Database (Denmark)

    Hauptmann, Aviaja Zenia Edna Lyberth

    Microbial biogeography has become a recognized field of research within the science of microbial ecology. Technological advances such as the high throughput sequencing of genetic information with next-generation sequencing (NGS) technologies have made us able to “see” the diversity of microbial...... communities. This has considerably improved our understanding that even harsh and seemingly barren environments such as the cryosphere, the frozen parts of our planet, is inhabited by diverse life. This thesis presents three studies in microbial biogeography of the Arctic cryosphere utilizing a range of NGS...... to a previously unacknowledged degree. The overall aim of this thesis is to illustrate the advantages that NGS has given in the field of microbial biogeography with the Arctic cryosphere as an example. The most important point in the following is that in order to utilize these advantages to their full potential...

  19. Satellite monitoring of impact Arctic regions (United States)

    Bondur, V. G.; Vorobev, V. E.


    The results of satellite monitoring of the environmental state of impact Arctic regions subjected to heavy anthropogenic influence are given. We analyze arrays of vegetation indices and complex spectral transformations derived from processed long-term (1973-2013) satellite data for areas around the cities of Arkhangelsk and Zapolyarny (Murmansk oblast). These data have been used to evaluate the changes in the state of the environment and reveal areas of peak anthropogenic impacts causing significant morphologic changes in all kinds of geosystems and strongly affecting the Arctic natural ecosystems. We have identified the impact regions that are subjected to peak anthropogenic impact and found that these areas are associated with specific industrial facilities.

  20. Carbon dioxide exchange in the Arctic

    DEFF Research Database (Denmark)

    Ravn, Nynne Marie Rand

    Low temperatures in the Arctic have through geological times caused a build-up of carbon (C) in the soil while carbon dioxide (CO2) has been removed from the atmosphere, because ecosystem respiration (ER) has been exceeded by the photosynthesis (GEP). Increasing air temperature, as occurring...... in current years, is likely to increase ER due to increased decomposition and increased substrate input e.g. due to permafrost thaw. If GEP is left unchanged and decomposition of old C from the soil is occurring this might result in an increase of the emission of CO2 to the atmosphere probably resulting...... fluxes and organic nutrient utilization between ecosystems occurring from different latitudes and dominated by different vegetation types. These aspects are important to understand the effects of climate change on the CO2 balance in the Arctic and its potential positive feedback on global climate change...

  1. Observing Arctic Ecology using Networked Infomechanical Systems (United States)

    Healey, N. C.; Oberbauer, S. F.; Hollister, R. D.; Tweedie, C. E.; Welker, J. M.; Gould, W. A.


    Understanding ecological dynamics is important for investigation into the potential impacts of climate change in the Arctic. Established in the early 1990's, the International Tundra Experiment (ITEX) began observational inquiry of plant phenology, plant growth, community composition, and ecosystem properties as part of a greater effort to study changes across the Arctic. Unfortunately, these observations are labor intensive and time consuming, greatly limiting their frequency and spatial coverage. We have expanded the capability of ITEX to analyze ecological phenomenon with improved spatial and temporal resolution through the use of Networked Infomechanical Systems (NIMS) as part of the Arctic Observing Network (AON) program. The systems exhibit customizable infrastructure that supports a high level of versatility in sensor arrays in combination with information technology that allows for adaptable configurations to numerous environmental observation applications. We observe stereo and static time-lapse photography, air and surface temperature, incoming and outgoing long and short wave radiation, net radiation, and hyperspectral reflectance that provides critical information to understanding how vegetation in the Arctic is responding to ambient climate conditions. These measurements are conducted concurrent with ongoing manual measurements using ITEX protocols. Our NIMS travels at a rate of three centimeters per second while suspended on steel cables that are ~1 m from the surface spanning transects ~50 m in length. The transects are located to span soil moisture gradients across a variety of land cover types including dry heath, moist acidic tussock tundra, shrub tundra, wet meadows, dry meadows, and water tracks. We have deployed NIMS at four locations on the North Slope of Alaska, USA associated with 1 km2 ARCSS vegetation study grids including Barrow, Atqasuk, Toolik Lake, and Imnavait Creek. A fifth system has been deployed in Thule, Greenland beginning in

  2. Politics of Sustainability in the Arctic

    DEFF Research Database (Denmark)

    Gad, Ulrik Pram; Jakobsen, Uffe; Strandsbjerg, Jeppe


    The concept of sustainability has become central in arctic politics. However, there is little agreement on what ‘sustainable’ means. For different actors (governments, indigenous people, NGOs, etc.) the concept implies different sets of opportunities and precautions. Sustainability, therefore......, is a much more fundamental idea to be further elaborated depending on contexts than a definable term with a specific meaning. This paper suggests a set of theoretical questions, which can provide the first steps toward a research agenda on the politics of sustainability. The approach aims to map and analyze...... the role of sustainability in political and economic strategies in the Arctic. Sustainability has become a fundamental concept that orders the relationship between the environment (nature) and development (economy), however, in the process rearticulating other concepts such as identity (society). Hence, we...

  3. Methane and Root Dynamics in Arctic Soil

    DEFF Research Database (Denmark)

    D'Imperio, Ludovica

    on the global climate. We investigated two aspects of arctic ecosystem dynamics which are not well represented in climatic models: i) soil methane (CH4) oxidation in dry heath tundra and barren soils and ii) root dynamics in wetlands. Field measurements were carried out during the growing season in Disko Island...... a large capacity to oxidize CH4 which seems mainly controlled by soil moisture. Short-term responses to climatic manipulations (1-2 years) suggest that increased winter snow precipitation may reduce CH4 oxidation rates due to increased soil moisture after thawing. On the other hand, increased summer air...... temperature may enhance soil CH4 oxidation rates as a consequence of increased soil temperature and evapotranspiration. Bearing in mind the large distribution of dry tundra soils over the Arctic and their strong potential to oxidize CH4, these ecosystems could play a central role in offsetting CH4 emissions...

  4. Heritage and Change in the Arctic

    DEFF Research Database (Denmark)

    be continuously negotiated. In Heritage and Change in the Arctic scholars from the social and human sciences explore change and transformation from two resource-inspired angles: it keeps a constant focus on the impact of change on tangible and intangible heritage, as well as on some of the cultural and social......In recent years, rapid changes to Arctic environments and conditions have spurred much analysis into the melting of sea and inland ice, the opening up of new sea routes, impacts on flora and fauna, and increased access to globally desired resources. In this book the focus is directed at a more...... as stakeholders, developers and wardens of resources. In times characterized by such change and ambivalence, heritage offers itself as a means by which a community can meaningfully relate to both past and future; but its use (and the inclusion and exclusion of particular identity-building elements) must also...

  5. A Distributed Approach to System-Level Prognostics (United States)

    Daigle, Matthew J.; Bregon, Anibal; Roychoudhury, Indranil


    Prognostics, which deals with predicting remaining useful life of components, subsystems, and systems, is a key technology for systems health management that leads to improved safety and reliability with reduced costs. The prognostics problem is often approached from a component-centric view. However, in most cases, it is not specifically component lifetimes that are important, but, rather, the lifetimes of the systems in which these components reside. The system-level prognostics problem can be quite difficult due to the increased scale and scope of the prognostics problem and the relative Jack of scalability and efficiency of typical prognostics approaches. In order to address these is ues, we develop a distributed solution to the system-level prognostics problem, based on the concept of structural model decomposition. The system model is decomposed into independent submodels. Independent local prognostics subproblems are then formed based on these local submodels, resul ting in a scalable, efficient, and flexible distributed approach to the system-level prognostics problem. We provide a formulation of the system-level prognostics problem and demonstrate the approach on a four-wheeled rover simulation testbed. The results show that the system-level prognostics problem can be accurately and efficiently solved in a distributed fashion.

  6. New prognostic biomarkers in multiple myeloma

    Directory of Open Access Journals (Sweden)

    Aneta Szudy-Szczyrek


    Full Text Available Multiple myeloma is a malignant neoplastic disease, characterized by uncontrolled proliferation and accumulation of plasma cells in the bone marrow, which is usually connected with production of a monoclonal protein. It is the second most common hematologic malignancy. It constitutes approximately 1% of all cancers and 10% of hematological malignancies. Despite the huge progress that has been made in the treatment of multiple myeloma in the past 30 years including the introduction of new immunomodulatory drugs and proteasome inhibitors, it is still an incurable disease. According to current data, the five-year survival rate is 45%. Multiple myeloma is a very heterogeneous disease with a very diverse clinical course, which is expressed by differences in effectiveness of therapeutic strategies and ability to develop chemoresistance. This diversity implies the need to define risk stratification factors that would help to create personalized and optimized therapy and thereby improve treatment outcomes. Prognostic markers that aim to objectively evaluate the risk of a poor outcome, relapse and the patient’s overall outcome are useful for this purpose. The existing, widely used prognostic classifications, such as the Salmon-Durie classification or ISS, do not allow for individualization of treatment. As a result of the development of diagnostic techniques, especially cytogenetics and molecular biology, we were able to discover a lot of new, more sensitive and specific prognostic factors. The paper presents recent reports on the role of molecular, cytogenetic and biochemical alterations in pathogenesis and prognosis of the disease.

  7. “An Arctic Great Power”? Recent Developments in Danish Arctic Policy

    DEFF Research Database (Denmark)

    Rahbek-Clemmensen, Jon


    Denmark has been a firm advocate for Arctic cooperation in the recent decade, most importantly as the initiator of the 2008 Ilulissat meeting. Two new strategic publications – a foreign policy report (Danish Diplomacy and Defence in a Time of Change) and a defense report (The Ministry of Defence...... the documents represent a break in Danish Arctic policy. It argues that the two documents represent continuation, rather than change. They show that the High North continues to become steadily more important on the Danish foreign policy agenda, although the region remains just one of several regional priorities...... for Denmark. They also continue the cooperation-oriented Danish Arctic policy and move this policy forward by adding more analysis of specific policy programs and initiatives that have long been on the agenda. These initiatives are meant to strengthen the Kingdom of Denmark’s High North profile, further...

  8. Chemical pollution in the Arctic and Sub-Arctic marine ecosystems: an overview of current knowledge

    Energy Technology Data Exchange (ETDEWEB)

    Savinova, T.N.; Gabrielsen, G.W.; Falk-Petersen, S.


    This report is part of a research project in the framework of the Norwegian-Russian Environmental Cooperation, which was initiated in 1991 to elucidate the present status of environmental contaminants in the highly sensitive Arctic aquatic ecosystem, with special focus on sea birds. Although these ecosystems are the least polluted areas in the world, they are contaminated. The main pathways of contamination into Arctic and sub-Arctic marine ecosystems are atmospheric transport, ocean currents and rivers and in some areas, dumping and ship accidents. A literature survey reveals: (1) there is a lack of data from several trophic levels, (2) previous data are difficult to compare with recent data because of increased quality requirement, (3) not much has been done to investigate the effects of contaminants on the cellular level, at individual or population levels. 389 refs., 7 figs., 32 tabs.

  9. Climate-derived tensions in Arctic security.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.; Strickland, James Hassler


    Globally, there is no lack of security threats. Many of them demand priority engagement and there can never be adequate resources to address all threats. In this context, climate is just another aspect of global security and the Arctic just another region. In light of physical and budgetary constraints, new security needs must be integrated and prioritized with existing ones. This discussion approaches the security impacts of climate from that perspective, starting with the broad security picture and establishing how climate may affect it. This method provides a different view from one that starts with climate and projects it, in isolation, as the source of a hypothetical security burden. That said, the Arctic does appear to present high-priority security challenges. Uncertainty in the timing of an ice-free Arctic affects how quickly it will become a security priority. Uncertainty in the emergent extreme and variable weather conditions will determine the difficulty (cost) of maintaining adequate security (order) in the area. The resolution of sovereignty boundaries affects the ability to enforce security measures, and the U.S. will most probably need a military presence to back-up negotiated sovereignty agreements. Without additional global warming, technology already allows the Arctic to become a strategic link in the global supply chain, possibly with northern Russia as its main hub. Additionally, the multinational corporations reaping the economic bounty may affect security tensions more than nation-states themselves. Countries will depend ever more heavily on the global supply chains. China has particular needs to protect its trade flows. In matters of security, nation-state and multinational-corporate interests will become heavily intertwined.

  10. A Compendium of Arctic Environmental Information (United States)


    warn- ing of possible future ice invasions during petroleum drill- ing operations in open-water conditions. Development of sea ice Several basic...Butterfly closures, medium: 10 Moleskin 12 x 2 inch: 1 Aspirin 5 grain: 25 tablets The medications ’ ’should be restricted to healthy young adults, not...Geology. Published by the American Association of Petroleum Geologists, Tulsa, Oklahoma, 1973. Rey, L. (ed.) (1982). The Arctic Ocean. John Wiley

  11. Canada : oil, gas, and the new Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Huebert, R. [Calgary Univ., AB (Canada). Dept. of Political Science; Calgary Univ., AB (Canada). Centre for Military and Strategic Studies


    This presentation provided a broad overview of the geopolitical issues affecting the massive transformation of the Arctic resulting from resource development, globalization, and climate change. Two Arctics are emerging, notably one European and one North American. Oil and gas companies are investing heavily in the North, and there is continued debate over pipelines and projects, but the viability of projects can shift abruptly from technological and political change. Recent examples include the emergence of shale gas, the possibility of the United States becoming a gas exporter, and the Deepwater Horizon disaster. In terms of Maritime jurisdictions and boundaries, a comparison was presented regarding the Canadian and Russian claims to the continental shelf. International cooperation and a commitment to peaceful means can be seen in the Ilulissat Declaration, the acceptance of the United Nations Convention of the Law of the Sea as rules, the scientific cooperation of Canada, the United States, and Denmark, and the recent boundary agreement between Russia and Norway. The positions of the main players in the new geopolitics of the North were outlined, particularly with respect to Russia, the United States, Norway, Denmark, and Canada. Their recent policy statements and developing arctic force capabilities were summarized. Canada's more assertive Arctic policy was outlined in more detail along with the country's base locations and recent security actions in the North. The main issues facing nations with interests in the North will be maritime and aerospace; understanding the new players on the scene; and new technological developments. 10 figs., 5 refs.

  12. Safeguarding Canadian Arctic Sovereignty Against Conventional Threats (United States)


    and copper. For instance, in 2003, Canada became 15 the world’s third largest diamond producer on a value basis behind Botswana and Russia, based...on only three mines discovered in its northern territories in the 1990s and exploited since 1998. 13 Local discoveries in the Arctic have redefined... mining provisions, even if it recognized that the portions relating to navigation and over flight reflect customary international law. 15 The

  13. Geolocating Russian sources for Arctic black carbon (United States)

    Cheng, Meng-Dawn


    To design and implement an effective emission control strategy for black carbon (BC), the locations and strength of BC sources must be identified. Lack of accurate source information from the Russian Federation has created difficulty for a range of research and policy activities in the Arctic because Russia occupies the largest landmass in the Arctic Circle. A project was initiated to resolve emission sources of BC in the Russian Federation by using the Potential Source Contribution Function (PSCF). It used atmospheric BC data from two Arctic sampling stations at Alert Nunavut, Canada, and Tiksi Bay, Russia. The geographical regions of BC emission sources in Russia were identified and summarized as follows: (1) a region surrounding Moscow, (2) regions in Eurasia stretching along the Ural Mountains from the White Sea to the Black Sea, and (3) a number of scattered areas from western Siberia to the Russian Far East. Particulate potassium ions, non-marine sulfate, and vanadium were used to assist in resolving the source types: forest fire/biomass burning, coal-fired power plant, and oil combustion. Correlating these maps with the BC map helped to resolve source regions of BC emissions and connect them to their corresponding source types. The results imply that a region south of Moscow and another north of the Ural Mountains could be significant BC sources, but none of the grid cells in these regions could be linked to forest fires, oil combustion, or coal-fired power plants based on these three markers.

  14. Vole abundance and reindeer carcasses determine breeding activity of Arctic foxes in low Arctic Yamal, Russia. (United States)

    Ehrich, Dorothee; Cerezo, Maite; Rodnikova, Anna Y; Sokolova, Natalya A; Fuglei, Eva; Shtro, Victor G; Sokolov, Aleksandr A


    High latitude ecosystems are at present changing rapidly under the influence of climate warming, and specialized Arctic species at the southern margin of the Arctic may be particularly affected. The Arctic fox (Vulpes lagopus), a small mammalian predator endemic to northern tundra areas, is able to exploit different resources in the context of varying tundra ecosystems. Although generally widespread, it is critically endangered in subarctic Fennoscandia, where a fading out of the characteristic lemming cycles and competition with abundant red foxes have been identified as main threats. We studied an Arctic fox population at the Erkuta Tundra Monitoring site in low Arctic Yamal (Russia) during 10 years in order to determine which resources support the breeding activity in this population. In the study area, lemmings have been rare during the last 15 years and red foxes are nearly absent, creating an interesting contrast to the situation in Fennoscandia. Arctic fox was breeding in nine of the 10 years of the study. The number of active dens was on average 2.6 (range 0-6) per 100 km2 and increased with small rodent abundance. It was also higher after winters with many reindeer carcasses, which occurred when mortality was unusually high due to icy pastures following rain-on-snow events. Average litter size was 5.2 (SD = 2.1). Scat dissection suggested that small rodents (mostly Microtus spp.) were the most important prey category. Prey remains observed at dens show that birds, notably waterfowl, were also an important resource in summer. The Arctic fox in southern Yamal, which is part of a species-rich low Arctic food web, seems at present able to cope with a state shift of the small rodent community from high amplitude cyclicity with lemming dominated peaks, to a vole community with low amplitude fluctuations. The estimated breeding parameters characterized the population as intermediate between the lemming fox and the coastal fox ecotype. Only continued

  15. Does the modified Glasgow Prognostic Score (mGPS) have a prognostic role in esophageal cancer? (United States)

    Walsh, Siun M; Casey, Sarah; Kennedy, Raymond; Ravi, Narayanasamy; Reynolds, John V


    The modified Glasgow Prognostic Score (mGPS), which combines indices of decreased plasma albumin and elevated CRP, has reported independent prognostic significance in colorectal cancer, but its value in upper gastrointestinal cancer is unclear. The aim of this study was to assess the prognostic significance of mGPS in patients with operable esophageal malignancy. Patients undergoing resection with curative intent between January 2008 and June 2013 were included. The mGPS was scored as 0, 1, or 2 based on CRP(>10 mg/L) and albumin(<35g/L). The mGPS score (0 vs. 1/2 combined) was correlated with patient and tumor characteristics, and operative and oncologic outcomes. Two hundred and twenty-three patients were included. Median (range) follow-up was 21(12-70) months. The mGPS was 0 in 174 patients(78%). mGPS was significantly associated with positive nodal status(P = 0.008) and stage ≥III (P = 0.017). There was a significant improvement in overall survival in patients with mGPS = 0 (47.8 vs. 37.5 months, P = 0.014) but in multivariate analysis, only TNM-stage and nodal status were found to be independent prognostic indicators. mGPS is associated with advanced stage but has no independent prognostic significance and does not impact on operative outcomes. Consequently, this data does not support its routine application in patient selection or prognostication. J. Surg. Oncol. 2016;113:732-737. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  16. Seasonal Clear-Sky Flux and Cloud Radiative Effect Anomalies in the Arctic Atmospheric Column Associated with the Arctic Oscillation and Arctic Dipole (United States)

    Hegyi, Bradley M.; Taylor, Patrick C.


    The impact of the Arctic Oscillation (AO) and Arctic Dipole (AD) on the radiative flux into the Arctic mean atmospheric column is quantified. 3-month-averaged AO and AD indices are regressed with corresponding surface and top-of-atmosphere (TOA) fluxes from the CERES-SFC and CERES-TOA EBAF datasets over the period 2000-2014. An increase in clear-sky fluxes into the Arctic mean atmospheric column during fall is the largest net flux anomaly associated with AO, primarily driven by a positive net longwave flux anomaly (i.e. increase of net flux into the atmospheric column) at the surface. A decrease in the Arctic mean atmospheric column cloud radiative effect during winter and spring is the largest flux anomaly associated with AD, primarily driven by a change in the longwave cloud radiative effect at the surface. These prominent responses to AO and AD are widely distributed across the ice-covered Arctic, suggesting that the physical process or processes that bring about the flux change associated with AO and AD are distributed throughout the Arctic.

  17. Prognostic factors in papillary and follicular thyroid carcinomas

    DEFF Research Database (Denmark)

    Godballe, C; Asschenfeldt, P; Jørgensen, K E


    To identify clinical and histologic prognostic factors and to investigate whether immunohistochemical detection of p53 expression might contain prognostic information, a retrospective study of patient and tumor characteristics was performed in 225 cases of papillary and follicular thyroid carcino...... prognostic indicator, which might be of value in the treatment planning in patients with papillary or follicular thyroid carcinomas.......To identify clinical and histologic prognostic factors and to investigate whether immunohistochemical detection of p53 expression might contain prognostic information, a retrospective study of patient and tumor characteristics was performed in 225 cases of papillary and follicular thyroid...... carcinomas. The analyses were based on cause-specific and crude survival. In univariate analysis, age at diagnosis, tumor size, presence of distant metastases, histology (papillary contra follicular type), extrathyroidal invasion, necrosis in primary tumor, and p53 expression were significant prognostic...

  18. Autonomous Observations of the Upper Ocean Stratification and Velocity Field about the Seasonality Retreating Marginal Ice Zone (United States)


    stratification and velocity field about the seasonality-retreating marginal ice zone 5b. GRANT NUMBER N00014-12-1-0140 Sc. PROGRAM ELEMENT NUMBER 6...STATEMENT UNLIMITED - UNCLASSIFIED 13. SUPPLEMENTARY NOTES 14. ABSTRACT As a contribution to the Marginal Ice Zone ORI, this research element was...understanding of the Arctic air-ice-ocean system. 15. SUBJECT TERMS Arctic Ocean Air-Ice-Ocean Interaction Marginal Ice Zone 16. SECURITY

  19. Autonomous Observations of the Upper Ocean Stratification and Velocity Field about the Seasonally-Retreating Marginal Ice Zone (United States)


    stratification and velocity field about the seasonality-retreating marginal ice zone Sb. GRANT NUMBER N00014-12-1 -0140 Sc. PROGRAM ELEMENT NUMBER 6...STATEMENT UNLIMITED- UNCLASSIFIED 13. SUPPLEMENTARY NOTES 14. ABSTRACT As a contribution to the Marginal Ice Zone DRI , this research element was...understanding of the Arctic air-ice-ocean system. 15. SUBJECT TERMS Arctic Ocean Air-Ice-Ocean Interaction Marginal Ice Zone 16. SECURITY

  20. Genetics differentiation between Arctic and Antarctic monothalamous foraminiferans

    DEFF Research Database (Denmark)

    Pawlowski, Jan; Majewski, Wojciech; Longet, David


    distinct genetically. As expected, Arctic specimens were usually more closely related to those from Northern Europe than to their Antarctic representatives. The deep-sea specimens from Weddell Sea branched as a sister to the McMurdo Sound population, while those from the Arctic Ocean clustered with ones...

  1. Physical properties of the arctic summer aerosol particles in relation ...

    Indian Academy of Sciences (India)

    The sea-salt particles of marine origin generated within the Arctic circle are identified as the main source of the Arctic summer aerosols. Total number concentration of aerosol particles increases with increase in wind speed, the increase being more when winds from open leads over the oceanic sector are reaching the ...

  2. Implementation of U.S. Policy in the Arctic (United States)


    Ballistic Missile Early Warning System, its Reserve units with LC-130 Hercules that are ski - 62 U.S. Navy, U.S. Marine Corps, U.S. Coast Guard, Naval...of Arctic and Alpine Research. The International Arctic Research Center is at the University of Alaska Fairbanks.123 Additionally, the NSF supports

  3. Global Warming Threatens National Interests in the Arctic (United States)


    Global warming has impacted the Arctic Ocean by significantly reducing the extent of the summer ice cover allowing greater access to the region...increased operations in the Arctic region, and DoD must continue to research and develop new and alternate energy sources for its forces. Global warming is

  4. Phase Zero Contracting for U.S. Arctic National Security (United States)


    Included is a literature review of national strategy and international policies, limited to specific research areas. Analysis of procurement stakeholder...contract actions are appropriate for Phase Zero of Arctic planning? Included is a literature review of national strategy and international policies...59 ix LIST OF FIGURES Figure 1. Graphic Representation of Arctic Area of Interest. Source: CNO (2014

  5. Siberian Arctic black carbon sources constrained by model and observation (United States)

    Winiger, Patrik; Andersson, August; Eckhardt, Sabine; Stohl, Andreas; Semiletov, Igor P.; Dudarev, Oleg V.; Charkin, Alexander; Shakhova, Natalia; Klimont, Zbigniew; Heyes, Chris; Gustafsson, Örjan


    Black carbon (BC) in haze and deposited on snow and ice can have strong effects on the radiative balance of the Arctic. There is a geographic bias in Arctic BC studies toward the Atlantic sector, with lack of observational constraints for the extensive Russian Siberian Arctic, spanning nearly half of the circum-Arctic. Here, 2 y of observations at Tiksi (East Siberian Arctic) establish a strong seasonality in both BC concentrations (8 ngṡm-3 to 302 ngṡm-3) and dual-isotope-constrained sources (19 to 73% contribution from biomass burning). Comparisons between observations and a dispersion model, coupled to an anthropogenic emissions inventory and a fire emissions inventory, give mixed results. In the European Arctic, this model has proven to simulate BC concentrations and source contributions well. However, the model is less successful in reproducing BC concentrations and sources for the Russian Arctic. Using a Bayesian approach, we show that, in contrast to earlier studies, contributions from gas flaring (6%), power plants (9%), and open fires (12%) are relatively small, with the major sources instead being domestic (35%) and transport (38%). The observation-based evaluation of reported emissions identifies errors in spatial allocation of BC sources in the inventory and highlights the importance of improving emission distribution and source attribution, to develop reliable mitigation strategies for efficient reduction of BC impact on the Russian Arctic, one of the fastest-warming regions on Earth.

  6. Adapting Governance and Regulation of the Marine Arctic

    NARCIS (Netherlands)

    Molenaar, Erik


    The Arctic is currently undergoing change at a pace many would not have considered possible just a decade or so ago. It is therefore reasonable to argue that while the international law and policy regime for the governance and regulation of the marine Arctic may have been adequate for an

  7. High-Arctic butterflies become smaller with rising temperatures

    DEFF Research Database (Denmark)

    Bowden, Joseph James; Eskildsen, Anne; Hansen, Rikke Reisner


    size but long growing seasons could also increase body size as was recently shown in an Arctic spider species. Here, we present the longest known time series on body size variation in two High-Arctic butterfly species: Boloria chariclea and Colias hecla. We measured wing length of nearly 4500...

  8. Glass Fiber Resin Composites and Components at Arctic Temperatures (United States)


    NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited GLASS FIBER RESIN ...3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE GLASS FIBER RESIN COMPOSITES AND COMPONENTS AT ARCTIC TEMPERATURES 5...dependent on the reaction between the fiber and the resin , but little research has been conducted that was geared toward naval applications at arctic

  9. Mercury associated neurochemical response in Arctic barnacle goslings (Branta leucopsis)

    NARCIS (Netherlands)

    Brink, van den Nico W.; Scheiber, Isabella B.R.; Jong, de Margje E.; Braun, Anna; Arini, Adeline; Basu, Niladri; Berg, van den Hans; Komdeur, Jan; Loonen, Maarten J.J.E.


    There remains great concern over mercury pollution in the Arctic, though relatively little is known about impacts on biota that inhabit Arctic terrestrial systems. To help address this, the current study was performed with barnacle goslings (Branta leucopsis) from a coal mine-impacted site and a

  10. Future-Proofing Japan’s Interests in the Arctic

    DEFF Research Database (Denmark)

    Tonami, Aki


    In May 2013 the Arctic states convened in Kiruna, Sweden, in part to decide on whether six new states should be admitted as observers to the Arctic Council. Japan’s application was accepted along with those of China,India, Italy, Singapore, and South Korea. At a glance, one might ask what credent...

  11. Conceptualizing delta forms and processes in Arctic coastal environments

    DEFF Research Database (Denmark)

    Bendixen, Mette; Kroon, Aart


    Climate warming in the Arctic directly causes two opposite changes in Arctic coastal systems: increased melt-water discharge through rivers induces extra influx of sediments and extended open water season increases wave impact which reworks and erodes the shores. A shoreline change analysis along...

  12. Changes in the Arctic: Background and Issues for Congress (United States)


    2012 Chicago Summit – likely at the insistence of Canada. See “NATO in the Arctic: Challenges and Opportunities,” by Luke Coffee , Heritage...Emelie Rutherford , “Coast Guard To Test How Ships and Aircraft Operate in Arctic,” Inside the Navy, January 21, 2008; Philip Ewiing, “Allen: CG

  13. The nature of spatial transitions in the Arctic. (United States)

    H. E. Epstein; J. Beringer; W. A. Gould; A. H. Lloyd; C. D. Thompson; F. S. Chapin III; G. J. Michaelson; C. L. Ping; T. S. Rupp; D. A. Walker


    Aim Describe the spatial and temporal properties of transitions in the Arctic and develop a conceptual understanding of the nature of these spatial transitions in the face of directional environmental change. Location Arctic tundra ecosystems of the North Slope of Alaska and the tundraforest region of the Seward Peninsula, Alaska. Methods We synthesize information from...

  14. The genetic prehistory of the New World Arctic

    DEFF Research Database (Denmark)

    Raghavan, Maanasa; DeGiorgio, Michael; Albrechtsen, Anders


    The New World Arctic, the last region of the Americas to be populated by humans, has a relatively well-researched archaeology, but an understanding of its genetic history is lacking. We present genome-wide sequence data from ancient and present-day humans from Greenland, Arctic Canada, Alaska...

  15. Deep Arctic Ocean warming during the last glacial cycle (United States)

    Cronin, T. M.; Dwyer, G.S.; Farmer, J.; Bauch, H.A.; Spielhagen, R.F.; Jakobsson, M.; Nilsson, J.; Briggs, W.M.; Stepanova, A.


    In the Arctic Ocean, the cold and relatively fresh water beneath the sea ice is separated from the underlying warmer and saltier Atlantic Layer by a halocline. Ongoing sea ice loss and warming in the Arctic Ocean have demonstrated the instability of the halocline, with implications for further sea ice loss. The stability of the halocline through past climate variations is unclear. Here we estimate intermediate water temperatures over the past 50,000 years from the Mg/Ca and Sr/Ca values of ostracods from 31 Arctic sediment cores. From about 50 to 11 kyr ago, the central Arctic Basin from 1,000 to 2,500 m was occupied by a water mass we call Glacial Arctic Intermediate Water. This water mass was 1–2 °C warmer than modern Arctic Intermediate Water, with temperatures peaking during or just before millennial-scale Heinrich cold events and the Younger Dryas cold interval. We use numerical modelling to show that the intermediate depth warming could result from the expected decrease in the flux of fresh water to the Arctic Ocean during glacial conditions, which would cause the halocline to deepen and push the warm Atlantic Layer into intermediate depths. Although not modelled, the reduced formation of cold, deep waters due to the exposure of the Arctic continental shelf could also contribute to the intermediate depth warming.

  16. Ecological dynamics across the Arctic associated with recent climate change (United States)

    Eric Post; Mads C. Forchhammer; M. Syndonia Bret-Harte; Terry V. Callaghan; Torben R. Christensen; Bo Elberling; Anthony D. Fox; Olivier Gilg; David S. Hik; Toke T. Høye; Rolf A. Ims; Erik Jeppesen; David R. Klein; Jesper Madsen; A. David McGuire; Søren Rysgaard; Daniel E. Schindler; Ian Stirling; Mikkel P. Tamstorf; Nicholas J.C. Tyler; Rene van der Wal; Jeffrey Welker; Philip A. Wookey; Niels Martin Schmidt; Peter. Aastrup


    At the close of the Fourth International Polar Year, we take stock of the ecological consequences of recent climate change in the Arctic, focusing on effects at population, community, and ecosystem scales. Despite the buffering effect of landscape heterogeneity, Arctic ecosystems and the trophic relationships that structure them have been severely perturbed. These...

  17. The Arctic Climate Modeling Program: Professional Development for Rural Teachers (United States)

    Bertram, Kathryn Berry


    The Arctic Climate Modeling Program (ACMP) offered yearlong science, technology, engineering, and math (STEM) professional development to teachers in rural Alaska. Teacher training focused on introducing youth to workforce technologies used in Arctic research. Due to challenges in making professional development accessible to rural teachers, ACMP…

  18. Arctic Tides from GPS on sea-ice

    DEFF Research Database (Denmark)

    Kildegaard Rose, Stine; Skourup, Henriette; Forsberg, René


    ) placed on sea-ice, at six different sites north of Greenland for the preliminary study of sea surface height (SSH), and tidal analysis to improve tide models in the Central Arctic. The GPS measurements are compared with the Arctic tide model AOTIM-5, which assimilates tide-gauges and altimetry data...

  19. The impact of Greenland's deglaciation on the Arctic circulation

    DEFF Research Database (Denmark)

    Dethloff, K.; Dorn, W.; Rinke, A.


    connected with shifts in the synoptic storm tracks during winter would have important consequences for the atmospheric freshwater input into the Arctic Ocean and the Nordic sea with the potential to cause variability in the Arctic Ocean dynamics on centennial to millennial time scales. The significant...

  20. The Alaska Arctic Vegetation Archive (AVA-AK)

    NARCIS (Netherlands)

    Walker, Donald A.; Breen, Amy L.; Druckenmiller, Lisa A.; Wirth, Lisa W.; Fisher, Will; Raynolds, Martha K.; Šibík, Jozef; Walker, Marilyn D.; Hennekens, Stephan; Boggs, Keith; Boucher, Tina; Buchhorn, Marcel; Bültmann, Helga; Cooper, David J.; Daniëls, Fred J.A.; Davidson, Scott J.; Ebersole, James J.; Elmendorf, Sara C.; Epstein, Howard E.; Gould, William A.; Hollister, Robert D.; Iversen, Colleen M.; Jorgenson, M.T.; Kade, Anja; Lee, Michael T.; MacKenzie, William H.; Peet, Robert K.; Peirce, Jana L.; Schickhoff, Udo; Sloan, Victoria L.; Talbot, Stephen S.; Tweedie, Craig E.; Villarreal, Sandra; Webber, Patrick J.; Zona, Donatella


    The Alaska Arctic Vegetation Archive (AVA-AK, GIVD-ID: NA-US-014) is a free, publically available database archive of vegetation-plot data from the Arctic tundra region of northern Alaska. The archive currently contains 24 datasets with 3,026 non-overlapping plots. Of these, 74% have geolocation

  1. Arctic methane sources: Isotopic evidence for atmospheric inputs

    NARCIS (Netherlands)

    Fisher, R.E.; Sriskantharajah, S.; Lowry, D.; Lanoisellé, M.; Fowler, C.M.R.; James, R.H.; Hermansen, O.; Lund Myhre, C.; Stohl, A.; Greinert, J.; Nisbet-Jones, P.B.R.; Mienert, J.; Nisbet, E.G.


    By comparison of the methane mixing ratio and the carbon isotope ratio (delta C-13(CH4)) in Arctic air with regional background, the incremental input of CH4 in an air parcel and the source delta C-13(CH4) signature can be determined. Using this technique the bulk Arctic CH4 source signature of air

  2. A Survey of Metrics for Performance Evaluation of Prognostics (United States)

    National Aeronautics and Space Administration — Prognostics is an emerging concept in condition basedmaintenance(CBM)ofcriticalsystems.Alongwith developing the fundamentals of being able to confidently predict...

  3. Distributed Prognostic Health Management with Gaussian Process Regression (United States)

    National Aeronautics and Space Administration — Distributed prognostics architecture design is an enabling step for efficient implementation of health management systems. A major challenge encountered in such...

  4. An Approach to Prognostic Decision Making in the Aerospace Domain (United States)

    National Aeronautics and Space Administration — The field of Prognostic Health Management (PHM) has been undergoing rapid growth in recent years, with development of increasingly sophisticated techniques for...

  5. Evaluating Prognostics Performance for Algorithms Incorporating Uncertainty Estimates (United States)

    National Aeronautics and Space Administration — Uncertainty Representation and Management (URM) are an integral part of the prognostic system development.1As capabilities of prediction algorithms evolve, research...

  6. Accelerated Aging Experiments for Capacitor Health Monitoring and Prognostics (United States)

    National Aeronautics and Space Administration — This paper discusses experimental setups for health monitoring and prognostics of electrolytic capacitors under nominal operation and accelerated aging conditions....

  7. Towards Arctic Resource Governance of Marine Invasive Species

    DEFF Research Database (Denmark)

    Kourantidou, Melina; Kaiser, Brooks; Fernandez, Linda


    research into invasive species threats in the Arctic, including the ways in which known marine invasions are related to different stakeholder groups and existing disparate national and international experiences with invasive species. Stakeholdergroups include dominant industries (fishing, shipping, tourism......Scientific and policy-oriented publications highlighting the magnitude of uncertainty in the changing Arctic and the possibilities for effective regional governance are proliferating, yet it remains a challenging task to examine Arctic marine biodiversity. Limited scientific data are currently...... available. Through analysis of marine invasions in the Arctic, we work to identify and assess patterns in the knowledge gaps regarding invasive species in the Arctic that affect the ability to generate improved governance outcomes. These patterns are expected to depend on multiple aspects of scientific...

  8. Enabling Use of Unmanned Aircraft Systems for Arctic Environmental Monitoring

    DEFF Research Database (Denmark)

    Storvold, Rune; la Cour-Harbo, Anders; Mulac, Brenda

    ) and their technology, offer a range of new and unique capabilities that can assist scientists in their quest for more data. In 2008, scientists from the eight Arctic countries came together and unanimously agreed that UAS are a key tool to understand the climate change occurring in the Arctic and its impact......The Arctic is undergoing rapid change as the coverage and thickness of sea ice is diminishing, glaciers and icecaps retreating and ecosystems are under stress. Scientists are scrambling to understand the many Arctic processes and mechanisms as a result of the rapid change. Research stations......, poor resolution, and the complicated surface of snow and ice. Measurements made from manned aircraft are also limited because of range and endurance, as well as the danger and costs presented by operating manned aircraft in harsh and remote environments like the Arctic. Unmanned aircraft systems (UAS...

  9. Enhanced role of eddies in the Arctic marine biological pump. (United States)

    Watanabe, Eiji; Onodera, Jonaotaro; Harada, Naomi; Honda, Makio C; Kimoto, Katsunori; Kikuchi, Takashi; Nishino, Shigeto; Matsuno, Kohei; Yamaguchi, Atsushi; Ishida, Akio; Kishi, Michio J


    The future conditions of Arctic sea ice and marine ecosystems are of interest not only to climate scientists, but also to economic and governmental bodies. However, the lack of widespread, year-long biogeochemical observations remains an obstacle to understanding the complicated variability of the Arctic marine biological pump. Here we show an early winter maximum of sinking biogenic flux in the western Arctic Ocean and illustrate the importance of shelf-break eddies to biological pumping from wide shelves to adjacent deep basins using a combination of year-long mooring observations and three-dimensional numerical modelling. The sinking flux trapped in the present study included considerable fresh organic material with soft tissues and was an order of magnitude larger than previous estimates. We predict that further reductions in sea ice will promote the entry of Pacific-origin biological species into the Arctic basin and accelerate biogeochemical cycles connecting the Arctic and subarctic oceans.

  10. Carbon, Climate and Cameras: Showcasing Arctic research through multimedia storytelling (United States)

    Tachihara, B. L.; Linder, C. A.; Holmes, R. M.


    In July 2011, Tachihara spent three weeks in the Siberian Arctic documenting The Polaris Project, an NSF-funded effort that brings together an international group of undergraduate students and research scientists to study Arctic systems. Using a combination of photography, video and interviews gathered during the field course, we produced a six-minute film focusing on the researchers' quest to track carbon as it moves from terrestrial upland areas into lakes, streams, rivers and eventually into the Arctic Ocean. The overall goal was to communicate the significance of Arctic science in the face of changing climate. Using a selection of clips from the 2011 video, we will discuss the advantages and challenges specific to using multimedia presentations to represent Arctic research, as well as science in general. The full video can be viewed on the Polaris website:

  11. Ekman circulation in the Arctic Ocean: Beyond the Beaufort Gyre (United States)

    Ma, Barry; Steele, Michael; Lee, Craig M.


    Data derived from satellite-based observations, with buoy-based observations and assimilations, are used to calculate ocean Ekman layer transport and evaluate long-term trends in the Arctic Ocean over the period 1979-2014. The 36 year mean of upwelling (downwelling) is 3.7 ± 2.0 (-4.0 ± 2.2) Sv for the entire Arctic Basin, with ˜0.3 Sv net downwelling contributed mostly by the Canadian region. With regard to long-term trends, the annual mean upwelling (downwelling) over the entire Arctic Basin is increasing at a linear rate of 0.92 (-0.98) Sv/decade. The Canada/Alaska coasts and Beaufort and Laptev Seas are regions of greatest Ekman transport intensification. The central Arctic Ocean and Lincoln Sea also have an increasing trend in transport. The Canadian and Eurasian regions each account for about half the total vertical Ekman variations in the Arctic Basin.

  12. Climate change and the ecology and evolution of Arctic vertebrates

    DEFF Research Database (Denmark)

    Gilg, Olivier; Kovacs, Kit M.; Aars, J.


    Climate change is taking place more rapidly and severely in the Arctic than anywhere on the globe, exposing Arctic vertebrates to a host of impacts. Changes in the cryosphere dominate the physical changes that already affect these animals, but increasing air temperatures, changes in precipitation...... already been documented. Changes in phenology and range will occur for most species but will only partly mitigate climate change impacts, which are particularly difficult to forecast due to the many interactions within and between trophic levels. Even though Arctic species richness is increasing via......, and ocean acidification will also affect Arctic ecosystems in the future. Adaptation via natural selection is problematic in such a rapidly changing environment. Adjustment via phenotypic plasticity is therefore likely to dominate Arctic vertebrate responses in the short term, and many such adjustments have...

  13. ARCTOX: a pan-Arctic sampling network to track mercury contamination across Arctic marine food webs

    DEFF Research Database (Denmark)

    Fort, Jerome; Helgason, Halfdan; Amelineau, Francoise

    . Sea-ice disappearance is opening new shipping areas to polluting human industries. The general warming of ocean water masses is expected to affect the cycle of Hg, thereby increasing exposure of marine organisms. Hence, Hg could have high impacts on Arctic organisms, biodiversity and ecosystems...

  14. Trophic pathways supporting Arctic grayling in a small stream on the Arctic Coastal Plain, Alaska (United States)

    McFarland, Jason J.; Wipfli, Mark S.; Whitman, Matthew S.


    Beaded streams are prominent across the Arctic Coastal Plain (ACP) of Alaska, yet prey flow and food web dynamics supporting fish inhabiting these streams are poorly understood. Arctic grayling (Thymallus arcticus) are a widely distributed upper-level consumer on the ACP and migrate into beaded streams to forage during the short 3-month open-water season. We investigated energy pathways and key prey resources that support grayling in a representative beaded stream, Crea Creek. We measured terrestrial invertebrates entering the stream from predominant riparian vegetation types, prey types supporting a range of fish size classes, and how riparian plants and fish size influenced foraging habits. We found that riparian plants influenced the quantity of terrestrial invertebrates entering Crea Creek; however, these differences were not reflected in fish diets. Prey type and size ingested varied with grayling size and season. Small grayling (fish (>15 cm FL) foraged most heavily on ninespine stickleback (Pungitius pungitius) throughout the summer, indicating that grayling can be insectivorous and piscivorous, depending on size. These findings underscore the potential importance of small streams in Arctic ecosystems as key summer foraging habitats for fish. Understanding trophic pathways supporting stream fishes in these systems will help interpret whether and how petroleum development and climate change may affect energy flow and stream productivity, terrestrial–aquatic linkages and fishes in Arctic ecosystems.

  15. Toxicokinetics and effects of PCBs in Arctic fish: a review of studies on Arctic charr (United States)

    Jorgensen, EH; Vijayan, M.N.; Killie, J.-E.A.; Aluru, N.; Aas-Hansen, O.; Maule, A.


    In a series of environmentally realistic laboratory experiments, toxicokinetics and effects of polychlorinated biphenyls (PCBs) were studied in the Arctic charr (Salvelinus alpinus). Winter fasting and emaciation, which are common among Arctic charr living in high latitudes, resulted in a redistribution of the lipophilic PCBs from lipid-storing tissue such as the muscle, to vital organs that must be considered sensitive toward PCB (liver and brain). This redistribution was accompanied by a significant potentiation of the hepatic cytochrome P-450 (CYP) 1A biomarker response, from low activities in October (within those measured in uncontaminated charr) to a high, probably maximum, induction in May. Performance studies demonstrated a clear effect of environmentally realistic PCB levels on endocrine mechanisms, immune function, and seawater preadaptation (smoltification) in charr that had been feed deprived for several months after contamination with Aroclor 1254, whereas a high PCB dose exerted only minor, if any, effects in charr that had been fed after contamination. These results demonstrate that emaciation results in decreased dose-response relationships in fish, and indicate that arctic animals undergoing seasonal cycles of "fattening" and emaciation may be extra sensitive toward persistent, lipophilic organochlorines. Pilot studies on Arctic charr from Bjørnøya Island revealed marked CYP1A biomarker responses and an upregulation of genes involved in cellular homeostatic mechanisms in charr from Lake Ellasjøen (high PCB levels).

  16. The Contribution to Arctic Climate Change from Countries in the Arctic Council (United States)

    Schultz, T.; MacCracken, M. C.


    The conventional accounting frameworks for greenhouse gas (GHG) emissions used today, established under the Kyoto Protocol 25 years ago, exclude short lived climate pollutants (SLCPs), and do not include regional effects on the climate. However, advances in climate science now suggest that mitigation of SLCPs can reduce up to 50% of global warming by 2050. It has also become apparent that regions such as the Arctic have experienced a much greater degree of anthropogenic warming than the globe as a whole, and that efforts to slow this warming could benefit the larger effort to slow climate change around the globe. A draft standard for life cycle assessment (LCA), LEO-SCS-002, being developed under the American National Standards Institute process, has integrated the most recent climate science into a unified framework to account for emissions of all radiatively significant GHGs and SLCPs. This framework recognizes four distinct impacts to the oceans and climate caused by GHGs and SLCPs: Global Climate Change; Arctic Climate Change; Ocean Acidification; and Ocean Warming. The accounting for Arctic Climate Change, the subject of this poster, is based upon the Absolute Regional Temperature Potential, which considers the incremental change to the Arctic surface temperature resulting from an emission of a GHG or SLCP. Results are evaluated using units of mass of carbon dioxide equivalent (CO2e), which can be used by a broad array of stakeholders, including scientists, consumers, policy makers, and NGOs. This poster considers the contribution to Arctic Climate Change from emissions of GHGs and SLCPs from the eight member countries of the Arctic Council; the United States, Canada, Russia, Denmark, Finland, Iceland, Norway, and Sweden. Of this group of countries, the United States was the largest contributor to Arctic Climate Change in 2011, emitting 9600 MMT CO2e. This includes a gross warming of 11200 MMT CO2e (caused by GHGs, black and brown carbon, and warming effects

  17. Operational Arctic: The Potential for Crisis or Conflict in the Arctic Region and Application of Operational Art (United States)


    Arctic ports such as Murmansk , Vladivostok, Anchorage, Reykjavik, or Oslo would see an increase in naval activity with the commercial boom of the... Murmansk , Fairbanks, or the Yukon Territory. Patrols and monitoring of their northern borders would be less than proposed in their respective Arctic

  18. Arctic patterned-ground ecosystems: A synthesis of field studies and models along a North American Arctic Transect (United States)

    Walker D.A.; Romanovsky V.E.; Ping C.L.; Michaelson G.J.; Daanen R.P.; Shur Y.; Peterson R.A.; Krantz W.B.; Raynolds M.K.; William Gould; Grizelle Gonzalez; Nicolsky D.J.; Vonlanthen C.M.; Kade A.N.; Kuss P.; Kelley A.M.; Munger C.A.; Tarnocai C.T.; Matveyeva N.V.; Daniels F.J.A.


    Arctic landscapes have visually striking patterns of small polygons, circles, and hummocks. The linkages between the geophysical and biological components of these systems and their responses to climate changes are not well understood. The “Biocomplexity of Patterned Ground Ecosystems” project examined patterned-ground features (PGFs) in all five Arctic bioclimate...

  19. The future of Arctic benthos: Expansion, invasion, and biodiversity (United States)

    Renaud, Paul E.; Sejr, Mikael K.; Bluhm, Bodil A.; Sirenko, Boris; Ellingsen, Ingrid H.


    One of the logical predictions for a future Arctic characterized by warmer waters and reduced sea-ice is that new taxa will expand or invade Arctic seafloor habitats. Specific predictions regarding where this will occur and which taxa are most likely to become established or excluded are lacking, however. We synthesize recent studies and conduct new analyses in the context of climate forecasts and a paleontological perspective to make concrete predictions as to relevant mechanisms, regions, and functional traits contributing to future biodiversity changes. Historically, a warmer Arctic is more readily invaded or transited by boreal taxa than it is during cold periods. Oceanography of an ice-free Arctic Ocean, combined with life-history traits of invading taxa and availability of suitable habitat, determine expansion success. It is difficult to generalize as to which taxonomic groups or locations are likely to experience expansion, however, since species-specific, and perhaps population-specific autecologies, will determine success or failure. Several examples of expansion into the Arctic have been noted, and along with the results from the relatively few Arctic biological time-series suggest inflow shelves (Barents and Chukchi Seas), as well as West Greenland and the western Kara Sea, are most likely locations for expansion. Apparent temperature thresholds were identified for characteristic Arctic and boreal benthic fauna suggesting strong potential for range constrictions of Arctic, and expansions of boreal, fauna in the near future. Increasing human activities in the region could speed introductions of boreal fauna and reduce the value of a planktonic dispersal stage. Finally, shelf regions are likely to experience a greater impact, and also one with greater potential consequences, than the deep Arctic basin. Future research strategies should focus on monitoring as well as compiling basic physiological and life-history information of Arctic and boreal taxa, and

  20. Climate Change: Science and Policy in the Arctic Climate Change: Science and Policy in the Arctic (United States)

    Bigras, S. C.


    It is an accepted fact that the Earth’s climate is warming. Recent research has demonstrated the direct links between the Arctic regions and the rest of the planet. We have become more aware that these regions are feeling the effects of global climate change more intensely than anywhere else on Earth -- and that they are fast becoming the new frontiers for resources and political disputes. This paper examines some of the potential climate change impacts in the Arctic and how the science of climate change can be used to develop policies that will help mitigate some of these impacts. Despite the growing body of research we do not yet completely understand the potential consequences of climate change in the Arctic. Climate models predict significant changes and impacts on the northern physical environment and renewable resources, and on the communities and societies that depend on them. Policies developed and implemented as a result of the research findings will be designed to help mitigate some of the more serious consequences. Given the importance of cost in making policy decisions, the financial implications of different scenarios will need to be considered. The Arctic Ocean Basin is a complex and diverse environment shared by five Arctic states. Cooperation among the states surrounding the Arctic Ocean is often difficult, as each country has its own political and social agenda. Northerners and indigenous peoples should be engaged and able to influence the direction of northern adaptation policies. Along with climate change, the Arctic environment and Arctic residents face many other challenges, among them safe resource development. Resource development in the Arctic has always been a controversial issue, seen by some as a solution to high unemployment and by others as an unacceptably disruptive and destructive force. Its inherent risks need to be considered: there are needs for adaptation, for management frameworks, for addressing cumulative effects, and for

  1. Prognostic indicators in alcoholic cirrhotic men

    DEFF Research Database (Denmark)

    Gluud, C; Henriksen, Jens Henrik Sahl; Nielsen, G


    The relationships between portal pressure, liver function and clinical variables on one hand and development of variceal hemorrhage and death on the other were investigated in 58 men with newly diagnosed alcoholic cirrhosis. Portal pressure was determined during hepatic vein catheterization...... information regarding development of variceal hemorrhage, even when easily obtained variables with known prognostic information were included [modified Child-Turcotte's criteria and incapacitation index (a weighted sum of days without normal health)]. During follow-up, 17 patients (29%) died. Applying Cox...... of prognosis in alcoholic cirrhotic men may be significantly improved by information about size of esophageal varices and level of portal pressure....

  2. Cellular prognostic markers in hepatocellular carcinoma. (United States)

    Buonaguro, Luigi; Tagliamonte, Maria; Petrizzo, Annacarmen; Damiano, Elvira; Tornesello, Maria Lina; Buonaguro, Franco M


    Hepatocellular carcinoma (HCC) is one of the five big killers worldwide and is frequently associated with chronic hepatitis B and C virus (HBV and HCV) infections. Tumor microenvironment consists of a complex network of cells and factors that plays a key role in the tumor progression and prognosis. This is true also for HCC. Several studies have shown strikingly strong correlation between HCC clinical prognosis and intratumoral infiltration of cells affecting tumor growth, invasion, angiogenesis and metastasis. None of such cells is yet validated for routine diagnostic and prognostic assessment. The present review aims at providing a state-of-the-art of such studies.

  3. Characterizing cytotoxic and estrogenic activity of Arctic char tissue extracts in primary Arctic char hepatocytes. (United States)

    Petersen, Karina; Hultman, Maria T; Bytingsvik, Jenny; Harju, Mikael; Evenset, Anita; Tollefsen, Knut Erik


    Contaminants from various anthropogenic activities are detected in the Arctic due to long-range atmospheric transport, ocean currents, and living organisms such as migrating fish or seabirds. Although levels of persistent organic pollutants (POPs) in Arctic fish are generally low, local hot spots of contamination were found in freshwater systems such as Lake Ellasjøen at Bjørnøya (Bear Island, Norway). Higher concentrations of organic halogenated compounds (OHC), and higher levels of cytochrome P450 and DNA-double strand breaks were reported in Arctic char (Salvelinus alpinus) from this lake compared to fish from other lakes on Bjørnøya. Although several of the measured contaminants are potential endocrine disrupters, few studies have investigated potential endocrine disruptive effects of the contaminant cocktail in this fish population. The aim of this study was to compare acutely toxic and estrogenic potency of the cocktail of pollutants as evidenced by cytotoxic and/or estrogenic effects in vitro using extracts of Arctic char livers from contaminated Lake Ellasjøen with those from less contaminated Lake Laksvatn at Bjørnøya. This was performed by in situ sampling and contaminant extraction from liver tissue, followed by chemical analysis and in vitro testing of the following contaminated tissue extracts: F1-nonpolar OHC, F2-polar pesticides and metabolites of OHC, and F3-polar OHC. Contaminant levels were highest in extracts from Ellasjøen fish. The F2 and F3 extracts from Lake Laksvatn and Lake Ellasjøen fish reduced in vitro cell viability at a concentration ratio of 0.03-1 relative to tissue concentration in Arctic char. Only the F3 liver extract from Ellasjøen fish increased in vitro vitellogenin protein expression. Although compounds such as estrogenic OH-PCBs were quantified in Ellasjøen F3 extracts, it remains to be determined which compounds were inducing estrogenic effects.

  4. The Arctic Observing Viewer (AOV): Visualization, Data Discovery, Strategic Assessment, and Decision Support for Arctic Observing (United States)

    Cody, R. P.; Manley, W. F.; Gaylord, A. G.; Kassin, A.; Villarreal, S.; Barba, M.; Dover, M.; Escarzaga, S. M.; Habermann, T.; Kozimor, J.; Score, R.; Tweedie, C. E.


    To better assess progress in Arctic Observing made by U.S. SEARCH, NSF AON, SAON, and related initiatives, an updated version of the Arctic Observing Viewer (AOV; has been released. This web mapping application and information system conveys the who, what, where, and when of "data collection sites" - the precise locations of monitoring assets, observing platforms, and wherever repeat marine or terrestrial measurements have been taken. Over 8000 sites across the circum-arctic are documented including a range of boreholes, ship tracks, buoys, towers, sampling stations, sensor networks, vegetation plots, stream gauges, ice cores, observatories, and more. Contributing partners are the U.S. NSF, ACADIS, ADIwg, AOOS, a2dc, AON, CAFF, GINA, IASOA, INTERACT, NASA ABoVE, and USGS, among others. Users can visualize, navigate, select, search, draw, print, view details, and follow links to obtain a comprehensive perspective of environmental monitoring efforts. We continue to develop, populate, and enhance AOV. Recent improvements include: a more intuitive and functional search tool, a modern cross-platform interface using javascript and HTML5, and hierarchical ISO metadata coupled with RESTful web services & metadata XLinks to span the data life cycle (from project planning to establishment of data collection sites to release of scientific datasets). Additionally, through collaborations with the Barrow Area Information Database (BAID, we are exploring linkages with datacenters and have developed a prototype dashboard application that allows users to explore data services in the AOV application. AOV is founded on principles of interoperability, such that agencies and organizations can use the AOV Viewer and web services for their own purposes. In this way, AOV complements other distributed yet interoperable cyber resources and helps science planners, funding agencies, investigators, data specialists, and others to: assess

  5. SEARCH: Study of Environmental Arctic Change--A System-scale, Cross-disciplinary Arctic Research Program (United States)

    Shnoro, R. S.; Eicken, H.; Francis, J. A.; Scambos, T. A.; Schuur, E. A.; Straneo, F.; Wiggins, H. V.


    SEARCH is an interdisciplinary, interagency program that works with academic and government agency scientists and stakeholders to plan, conduct, and synthesize studies of Arctic change. Over the past three years, SEARCH has developed a new vision and mission, a set of prioritized cross-disciplinary 5-year goals, an integrated set of activities, and an organizational structure. The vision of SEARCH is to provide scientific understanding of arctic environmental change to help society understand and respond to a rapidly changing Arctic. SEARCH's 5-year science goals include: 1. Improve understanding, advance prediction, and explore consequences of changing Arctic sea ice. 2. Document and understand how degradation of near-surface permafrost will affect Arctic and global systems. 3. Improve predictions of future land-ice loss and impacts on sea level. 4. Analyze societal and policy implications of Arctic environmental change. Action Teams organized around each of the 5-year goals will serve as standing groups responsible for implementing specific goal activities. Members will be drawn from academia, different agencies and stakeholders, with a range of disciplinary backgrounds and perspectives. 'Arctic Futures 2050' scenarios tasks will describe plausible future states of the arctic system based on recent trajectories and projected changes. These scenarios will combine a range of data including climate model output, paleo-data, results from data synthesis and systems modeling, as well as expert scientific and traditional knowledge. Current activities include: - Arctic Observing Network (AON) - coordinating a system of atmospheric, land- and ocean-based environmental monitoring capabilities that will significantly advance our observations of arctic environmental conditions. - Arctic Sea Ice Outlook - an international effort that provides monthly summer reports synthesizing community estimates of the expected sea ice minimum. A newly-launched Sea Ice Prediction Network

  6. A new prognostic index (MIPI) for patients with advanced-stage mantle cell lymphoma

    NARCIS (Netherlands)

    Hoster, Eva; Dreyling, Martin; Klapper, Wolfram; Gisselbrecht, Christian; van Hoof, Achiel; Kluin-Nelemans, Hanneke C.; Pfreundschuh, Michael; Reiser, Marcel; Metzner, Bernd; Einsele, Hermann; Peter, Norma; Jung, Wolfram; Woermann, Bernhard; Ludwig, Wolf-Dieter; Duehrsen, Ulrich; Eimermacher, Hartmut; Wandt, Hannes; Hasford, Joerg; Hiddemann, Wolfgang; Unterhalt, Michael


    There is no generally established prognostic index for patients with mantle cell lymphoma (MCL), because the International Prognostic Index (IPI) and Follicular Lymphoma International Prognostic Index (FLIPI) have been developed for diffuse large cell and follicular lymphoma patients, respectively.

  7. Debating the Arctic during the Ukraine Crisis – Comparing Arctic State Identities and Media Discourses in Canada and Norway

    DEFF Research Database (Denmark)

    Burke, Danita Catherine; Rahbek-Clemmensen, Jon


    Previous studies have argued that domestic factors, including each state’s Arctic state identities, may explain why some Western states (e.g. Canada) have been more critical of Russia in the Arctic than others (e.g. Norway). The present study analyses part of the link between Arctic state...... identities and foreign policy by showing that these identifications affected domestic media discourses about the Arctic in Canada and Norway during the first years (2014-16) of the Crisis. Canada’s territorial identification made it difficult for the newly elected Trudeau government to push for a less...... assertive course vis-à-vis Russia. In Norway, the strong economic discourse coloured early debates about the crisis, but after the widening of economic sanctions against Russia in the summer of 2014, territorial discourses played a more important role. The article thus illustrates that Arctic state...

  8. Climate change, future Arctic Sea ice, and the competitiveness of European Arctic offshore oil and gas production on world markets. (United States)

    Petrick, Sebastian; Riemann-Campe, Kathrin; Hoog, Sven; Growitsch, Christian; Schwind, Hannah; Gerdes, Rüdiger; Rehdanz, Katrin


    A significant share of the world's undiscovered oil and natural gas resources are assumed to lie under the seabed of the Arctic Ocean. Up until now, the exploitation of the resources especially under the European Arctic has largely been prevented by the challenges posed by sea ice coverage, harsh weather conditions, darkness, remoteness of the fields, and lack of infrastructure. Gradual warming has, however, improved the accessibility of the Arctic Ocean. We show for the most resource-abundant European Arctic Seas whether and how a climate induced reduction in sea ice might impact future accessibility of offshore natural gas and crude oil resources. Based on this analysis we show for a number of illustrative but representative locations which technology options exist based on a cost-minimization assessment. We find that under current hydrocarbon prices, oil and gas from the European offshore Arctic is not competitive on world markets.


    Directory of Open Access Journals (Sweden)

    M. Dudin


    Full Text Available In this article and summarized the regularities of formation of foreign experience and trends of development of Arctic territories. Set out the important points predetermine orientation and specificity of manifestations of national interests – potential participants of the subsoil in the Arctic zone. On the basis of the illuminated materials were obtained the following conclusions: Signifi cant interest in the Arctic show today, not only the fi ve countries (Russia, USA, Canada, Norway, Denmark, who own Arctic territories, but also polar state (Iceland, Sweden, Finland, the European Union and Asia. As a consequence of that, it is expected that in the XXI century the Arctic region will be the focus of attention as an official Arctic 45, and a number of states whose territory is quite removed from it; For Russia, given the current, acute political conditions (sanctions, confrontation with the West, Ukrainian crisis and war in the Middle East development of Arctic territories, some moved away, moved on tomorrow and the day after tomorrow on the agenda. This approach is fundamentally fl awed and fraught with a number of threats, because other countries do not decrease, but only increase their interest in this issue; Territorial opposition to all those involved in the topic of causing instability in the Arctic region, but does not represent a real threat for the emergence of large-scale conflict. Therefore, making the choice between the hard pressure of national interests and the interests of harmonization of the Arctic states, Russia must be based on international cooperationand mutual consideration of interests in the development of its Arctic strategy; Considering the cooperation of the countries of the Arctic Council and their cooperation in the framework of a global economic forum G8, there are prerequisites for the decision of the Arctic confl ict through negotiation and compromise. In this context it is very important to develop

  10. Shrub water use dynamics in arctic Alaska (United States)

    Clark, J.; Young-Robertson, J. M.; Tape, K. D.


    In the Arctic tundra, hydrologic processes influence the majority of ecosystem processes, from soil thermal dynamics to energy balance and trace gas exchange to vegetation community distributions. The tundra biome is experiencing a broad spectrum of ecosystem changes spurred by 20th century warming, including deciduous shrub expansion. Deciduous woody vegetation typically has high water use rates compared to evergreen and herbaceous species, and is projected to have a greater impact on energy balance than altered albedo from changes in snowpack. However, the impact of greater shrub cover on water balance has been overlooked. Shrubs have the potential to significantly dry the soil, accessing stored soil moisture in the organic layers, while increasing atmospheric moisture. The goal of this study is to quantify the water use dynamics (sap flux and stem water content) of three common arctic shrub species (Salix alexensis, S. pulchra, Betula nana) over two growing seasons. Stem water content was measured through a novel application of time domain reflectometry (TDR). Maximum sap flow rates varied by species: S. alexensis-600g/hr, S. pulchra-60g/hr, and B. nana-40g/hr. We found daily sap flow rates are highly correlated with atmospheric moisture demand (VPD) and not limited by soil moisture or antecedent precipitation. Stem water content varied between 20% and 60%, was correlated with soil moisture, and showed weak diurnal variation. This is one of the first studies to provide a detailed look at arctic tundra shrub water balance and explore the environmental controls on water flux. Planned future work will expand on these results for estimates of evapotranspiration over larger landscape areas.

  11. Arctic stratospheric dehydration - Part 2: Microphysical modeling (United States)

    Engel, I.; Luo, B. P.; Khaykin, S. M.; Wienhold, F. G.; Vömel, H.; Kivi, R.; Hoyle, C. R.; Grooß, J.-U.; Pitts, M. C.; Peter, T.


    Large areas of synoptic-scale ice PSCs (polar stratospheric clouds) distinguished the Arctic winter 2009/2010 from other years and revealed unprecedented evidence of water redistribution in the stratosphere. A unique snapshot of water vapor repartitioning into ice particles was obtained under extremely cold Arctic conditions with temperatures around 183 K. Balloon-borne, aircraft and satellite-based measurements suggest that synoptic-scale ice PSCs and concurrent reductions and enhancements in water vapor are tightly linked with the observed de- and rehydration signatures, respectively. In a companion paper (Part 1), water vapor and aerosol backscatter measurements from the RECONCILE (Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions) and LAPBIAT-II (Lapland Atmosphere-Biosphere Facility) field campaigns have been analyzed in detail. This paper uses a column version of the Zurich Optical and Microphysical box Model (ZOMM) including newly developed NAT (nitric acid trihydrate) and ice nucleation parameterizations. Particle sedimentation is calculated in order to simulate the vertical redistribution of chemical species such as water and nitric acid. Despite limitations given by wind shear and uncertainties in the initial water vapor profile, the column modeling unequivocally shows that (1) accounting for small-scale temperature fluctuations along the trajectories is essential in order to reach agreement between simulated optical cloud properties and observations, and (2) the use of recently developed heterogeneous ice nucleation parameterizations allows the reproduction of the observed signatures of de- and rehydration. Conversely, the vertical redistribution of water measured cannot be explained in terms of homogeneous nucleation of ice clouds, whose particle radii remain too small to cause significant dehydration.

  12. CANOZE measurements of the Arctic ozone hole (United States)

    Evans, W. F. J.; Kerr, J. B.; Fast, H.


    In CANOZE 1 (Canadian Ozone Experiment), a series of 20 ozone profile measurements were made in April, 1986 from Alert at 82.5 N. CANOZE is the Canadian program for study of the Arctic winter ozone layer. In CANOZE 2, ozone profile measurements were made at Saskatoon, Edmonton, Churchill and Resolute during February and March, 1987 with ECC ozonesondes. Ground based measurements of column ozone, nitrogen dioxide and hydrochloric acid were conducted at Saskatoon. Two STRATOPROBE balloon flights were conducted on February 26 and March 19, 1987. Two aerosol flights were conducted by the University of Wyoming. The overall results of this study will be reported and compared with the NOZE findings. The results from CANOZE 3 in 1988, are also discussed. In 1988, as part of CANOZE 3, STRATOPROBE balloon flights were conducted from Saskatchewan on January 27 and February 13. A new lightweight infrared instrument was developed and test flown. A science flight was successfully conducted from Alert (82.5 N) on March 9, 1988 when the vortex was close to Alert; a good measurement of the profile of nitric acid was obtained. Overall, the Arctic spring ozone layer exhibits many of the features of the Antarctic ozone phenomenon, although there is obviously not a hole present every year. The Arctic ozone field in March, 1986 demonstrated many similarities to the Antarctic ozone hole. The TOMS imagery showed a crater structure in the ozone field similar to the Antarctic crater in October. Depleted layers of ozone were found in the profiles around 15 km, very similar to those reported from McMurdo. Enhanced levels of nitric acid were measured in air which had earlier been in the vortex. The TOMS imagery for March 1987 did not show an ozone crater, but will be examined for an ozone crater in February and March, 1988, the target date for the CANOZE 3 project.

  13. The Atmospheric boundary layer over Arctic fjords

    Energy Technology Data Exchange (ETDEWEB)

    Kilpelaeinen, Tiina


    Arctic fjords represent one of the most challenging environments in the world for weather prediction and climate models. This is due to complex interactions between the large-scale weather conditions, land, sea, sea ice and surrounding topography consisting of mountains, valleys and glaciers. This thesis describes some special characteristics of the lowest part of the atmosphere over fjords in Svalbard. The main research topics are 1) the exchange of energy between the atmosphere and sea, 2) vertical structure of temperature, humidity and wind, 3) spatial variability of the meteorological variables and 4) identifying the main challenges for the weather prediction models. Kilpelaeinen has collected data using weather masts and tethered balloons at the coasts of fjords in Svalbard. In addition, she has made high-resolution simulations of the meteorological conditions over Svalbard fjords with a weather prediction model. Kilpelaeinens investigations show that the vertical profiles of temperature, humidity and wind over Arctic fjords are complex and therefore challenging for the weather prediction models to capture. Layers with a temperature and humidity increase with height are commonly found over Svalbard fjords, often even on multiple levels. A weather prediction model does not realistically capture these layers, which leads to fairly large errors in the modeled surface variables. Further, she found that a wind maximum at a low altitude is also a typical feature over Arctic fjords. The height of this wind maximum depends on the sea-ice conditions, being highest when sea ice is present. The thesis points out that due to the complex topography and the surface types (sea ice and water), spatial variability of meteorological variables within a fjord is very large and can reach levels comparable to the temporal variability. Hence, a high horizontal resolution in the order of 1 km is needed in the weather prediction models to realistically simulate all the significant

  14. New constraints on the early Paleozoic history of Arctic Alaska and its bearing on Arctic tectonic reconstructions (United States)

    Strauss, J. V.; Macdonald, F. A.; Taylor, J.; Repetski, J.; McClelland, W.


    Arctic Alaska is a large composite terrane that underlies the North Slope of Alaska and makes up the majority of the E-W-trending Brooks Range. Neoproterozoic and early Paleozoic connections between Arctic Alaska and Laurentia have been questioned because of the proposed differences in stratigraphic architecture, faunal affinities of mega- and microfossils, and various geochronological data. These studies have largely regarded Arctic Alaska as a single crustal fragment (i.e., Arctic Alaska-Chukotka microplate) with the majority of Neoproterozoic and early Paleozoic comparisons being drawn from the southern Hammond and Seward subterranes of Arctic Alaska. A combined approach of geological mapping and logging of detailed stratigraphic sections integrated with chemostratigraphic, biostratigraphic, and geochronologic analyses from the North Slope subterrane enables new interpretations of the pre-Mesozoic geologic history of Arctic Alaska. Specifically, we 1) disprove the existence of an angular unconformity between the Neoproterozoic Katakturuk Dolomite and Cambrian-Ordovician Nanook Limestone, 2) recognize and divide the Nanook Limestone into two new informal members separated by a major hiatus, and 3) provide evidence for a significant tectonically-driven exposure event prior to deposition of the Lower Devonian Mt. Copleston Limestone. Based on its stratigraphic architecture and faunal affinities, we suggest that the North Slope subterrane is parautochthonous to northern Laurentia and was separate from the exotic southern subterranes of Arctic Alaska until at least the latest Ordovician. Furthermore, we posit that the North Slope subterrane was juxtaposed and eventually incorporated into the composite Arctic Alaska-Chukotka microplate when this large crustal fragment collided with the northern margin of Laurentia during the Silurian-Devonian Innuitian and Ellesmerian orogenies. Future work will continue to unravel the complex Neoproterozoic-early Paleozoic geologic

  15. Trichinella infections in arctic foxes from Greenland

    DEFF Research Database (Denmark)

    Kapel, C. M O; Henriksen, S. A.; Berg, T. B.


    Studies were carried out to determine the predilection sites of Trichinella nativa muscle larvae in arctic foxes (Alopex lagopus) caught in Greenland. The highest number of larvae per gram of tissue was found in the muscles of the eyes and the legs. With regard to predilection sites no significant...... differences were demonstrated either between age groups or between foxes with high and low total parasite burdens. Predilection sites were comparable with those recorded earlier in experimentally infected caged foxes and in other carnivorous species. Hypotheses on predilection sites of Trichinella muscle...

  16. Trichinella in arctic, subarctic and temperate regions

    DEFF Research Database (Denmark)

    Kapel, C. M O


    and the human activity are all very important interacting factors affecting epidemiology. In Greenland, where only sylvatic trichinellosis is present, the high prevalence in wildlife appears closely connected with polar bear hunting. In the Scandinavian countries, the prevalence of both sylvatic and domestic......The transmission and occurrence of Trichinella spp according to the zoogeography of different climatic conditions, socioeconomy and human activity are discussed. Comparing arctic, subarctic and temperate regions, it appears that the species of Trichinella present, the composition of the fauna...... populations may have epidemiological importance in relation to the recent changes in production and infrastructure in these former Soviet states....

  17. Moving Facts in an Arctic field

    DEFF Research Database (Denmark)

    Hastrup, Kirsten Blinkenberg; Flora, Janne; Andersen, Astrid Oberborbeck


    where the team could go ashore in places that would otherwise have been difficult to access, and where the individual perspectives could cross-fertilize each other in actual practice. It is argued that anthropology itself is a mode of experimentation in practice, which enables new trains of thought......This article reflects on the merits of the expedition as an anthropological method on the basis of a recent cross-disciplinary experience, involving biologists, archaeologists and anthropologists working together in High Arctic Greenland. True to the term, the expedition had chartered a vessel from...

  18. Changing characteristics of arctic pressure ridges (United States)

    Wadhams, Peter; Toberg, Nick


    The advent of multibeam sonar permits us to obtain full three-dimensional maps of the underside of sea ice. In particular this enables us to distinguish the morphological characteristics of first-year (FY) and multi-year (MY) pressure ridges in a statistically valid way, whereas in the past only a small number of ridges could be mapped laboriously by drilling. In this study pressure ridge distributions from two parts of the Arctic Ocean are compared, in both the cases using mainly data collected by the submarine “Tireless” in March 2007 during two specific grid surveys, in the Beaufort Sea at about 75° N, 140° W (N of Prudhoe Bay), and north of Ellesmere Island at about 83° 20‧ N, 64° W. In the Beaufort Sea the ice was mainly FY, and later melted or broke up as this area became ice-free during the subsequent summer. N of Ellesmere Island the ice was mainly MY. Ridge depth and spacing distributions were derived for each region using the boat's upward looking sonar, combined with distributions of shapes of the ridges encountered, using the Kongsberg EM3002 multibeam sonar. The differing shapes of FY and MY ridges are consistent with two later high-resolution multibeam studies of specific ridges by AUV. FY ridges are found to fit the normal triangular shape template in cross-section (with a range of slope angles averaging 27°) with a relatively constant along-crest depth, and often a structure of small ice blocks can be distinguished. MY ridges, however, are often split into a number of independent solid, smooth blocks of large size, giving an irregular ridge profile which may be seemingly without linearity. Our hypothesis for this difference is that during its long lifetime an MY ridge is subjected to several episodes of crack opening; new cracks in the Arctic pack often run in straight lines across the ridges and undeformed ice alike. Such a crack will open somewhat before refreezing, interpolating a stretch of thin ice into the structure, and breaking up

  19. Sedimentary Cover of the Central Arctic (United States)

    Kireev, Artem; Poselov, Viktor; Butsenko, Viktor; Smirnov, Oleg


    Partial revised Submission of the Russian Federation for establishment of the OLCS (outer limit of the continental shelf) in the Arctic Ocean is made to include in the extended continental shelf of the Russian Federation, in accordance with article 76 of the Convention, the seabed and its subsoil in the central Arctic Ocean which is natural prolongation of the Russian land territory. To submit partial revised Submission in 2016, in 2005 - 2014 the Russian organizations carried out a wide range of geophysical studies, so that today over 23000 km of MCS lines, over hundreds of wide-angle reflection/refraction seismic sonobuoy soundings and 4000 km of deep seismic sounding are accomplished. All of these MCS and seismic soundings data were used to establish the seismic stratigraphy model of the Arctic region. Stratigraphy model of the sedimentary cover was successively determined for the Cenozoic and pre-Cenozoic parts of the section and was based on correlation of the Russian MCS data and seismic data documented by existing boreholes. Interpretation of the Cenozoic part of the sedimentary cover was based on correlation of the Russian MCS data and AWI91090 section calibrated by ACEX-2004 boreholes on the Lomonosov Ridge for Amerasia basin and by correlation of onlap contacts onto oceanic crust with defined magnetic anomalies for Eurasia basin, while interpretation of the Pre-Cenozoic part of the sedimentary cover was based on correlation with MCS and boreholes data from Chukchi sea shelf. Six main unconformities were traced: regional unconformity (RU), Eocene unconformity (EoU) (for Eurasia basin only), post-Campanian unconformity (pCU), Brookian (BU - base of the Lower Brookian unit), Lower Cretaceous (LCU) and Jurassic (JU - top of the Upper Ellesmerian unit). The final step in our research was to estimate the total thickness of the sedimentary cover of the Arctic Ocean and adjacent Eurasian shelf using top of acoustic basement correlation data and bathymetry data

  20. Collapsing permafrost coasts in the Arctic (United States)

    Fritz, Michael; Lantuit, Hugues


    Arctic warming is exposing permafrost coastlines, which account for 34% of the Earth's coasts, to rapid thaw and erosion. Coastal erosion rates as high as 25 m yr-1 together with the large amount of organic matter frozen in permafrost are resulting in an annual release of 14.0 Tg (1012 gram) particulate organic carbon into the nearshore zone. The nearshore zone is the primary recipient of higher fluxes of carbon and nutrients from thawing permafrost. We highlight the crucial role the nearshore zone plays in Arctic biogeochemical cycling, as here the fate of the released material is determined to: (1) degrade into greenhouse gases, (2) fuel marine primary production, (3) be buried in nearshore sediments or (4) be transported offshore. With Arctic warming, coastal erosion fluxes have the potential to increase by an order of magnitude until 2100. Such increases would result in drastic impacts on global carbon fluxes and their climate feedbacks, on nearshore food webs and on local communities, whose survival still relies on marine biological resources. Quantifying the potential impacts of increasing erosion on coastal ecosystems is crucial for food security of northern residents living in Arctic coastal communities. We need to know how the traditional hunting and fishing grounds might be impacted by high loads of sediment and nutrients released from eroding coasts, and to what extent coastal retreat will lead to a loss of natural habitat. Quantifying fluxes of organic carbon and nutrients is required, both in nearshore deposits and in the water column by sediment coring and systematic oceanographic monitoring. Ultimately, this will allow us to assess the transport and degradation pathways of sediment and organic matter derived from erosion. We need to follow the complete pathway, which is multi-directional including atmospheric release, lateral transport, transitional retention in the food web, and ultimate burial in seafloor sediments. We present numbers of multi