328,099 research outputs found

    Twentieth Anniversary of Expéditions Polaires Françaises (Missions Paul-Emile Victor)

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    Summarizes the activities of the EPF, founded by decision of the French Cabinet 27 Feb 1947 to carry out research in the earth and life sciences in polar regions. On its first expeditions, to Greenland in May and to Adelie Land, Antarctica in Nov 1948, the EPF introduced new techniques with motorized tractor convoys, air transport, parachutes and materials now in common use. EPF studies of the Greenland inland ice 1948-53 became international in collaboration with American Armed Forces 1952-58. In 1956 EPF assumed the technical and logistics organization and operational direction of the International Glaciological Expedition to Greenland (EGIG) at the request of the Snow and Ice Commission of the International Association for Scientific Hydrology: Austria, Denmark, France, Germany and Switzerland participated. Its operations, in 1957-60 and 1964-68, utilized several hundred men, air support, tracked vehicles, trailors on runners, sleds, etc. Its winter station, Jarl-Joset Station was constructed of prefabricated panels of a fiberglass-polyester composite material over a cellular core

    Glaciological Studies of the Mendenhall Glacier, Alaska

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    In May 1960 a group of Japanese scientists from Hokkaido University, led by Dr. Akira Higashi, left Yokohama for Alaska to conduct a study of the Mendenhall Glacier for a period of 6 weeks. ... Objectives of the project were the collecting of large single ice crystals at a lake at the terminus of Mendenhall Glacier and glaciological investigations of the glacier to elucidate the mechanism of the formation of large single ice crystals. Single ice crystals of large size are urgently needed by physicists at Hokkaido University, who are studying the solid state physics of ice crystals. ... The planned glaciological investigations include measurements of the speed of flow at various points of the glacier; determination of crystal orientation, grain size, and impurity content in the crystal grain and grain boundary for each sample taken at different places. A geological survey of nunataks and cirques near the upper part of the glacier and studies of firn snow were also planned, as well as comparative studies of the Taku Glacier, which is apparently different from the Mendenhall Glacier in many respects. The work schedule was planned as follows: first week, aircraft reconnaissance of the glacier and the Juneau Ice Field, determination of the location of observation sites from air photographs, establishment of a base camp at the terminus of the glacier; second week, search for and collecting of large single ice crystals at the glacier snout and putting them into cold storage in Juneau, establishing a base line across the glacier near the terminus for the determination of the speed of flow; third week, move to the second camp, routine glaciological work at two crevasses of medium altitudes; fourth week, move to the third camp glaciological work at two crevasses of high altitudes, special work on the firn of the ice field and on the geology of nunataks and cirques at the upper part of the glacier; fifth week, move to Taku Glacier, comparative studies of ice at the lower part of the glacier; sixth week, move to the upper part of Taku Glacier and continuation of the work of the previous week on the higher part of the glacier. The project has been supported in part by the Arctic Institute of North America under contract with the Office of Naval Research and by Hokkaido University

    An inter-comparison of Arctic synoptic scale storms between four global reanalysis datasets

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    The Arctic is becoming more accessible as sea ice extent continues to decline, resulting in higher human exposure to Arctic storms. This study compares Arctic storm characteristics between the ECMWF-Interim Reanalysis, 55-year Japanese Reanalysis, NASA-Modern Era Retrospective Analysis for Research and Applications Version 2 and National Centre for Environmental Prediction-Climate Forecast System Reanalysis datasets between 1980 and 2017, in winter (DJF) and summer (JJA). It is shown that Arctic storm characteristics are sensitive to the variable used for storm tracking. Arctic storm frequency is found to be similar in summer and winter when using sea level pressure minima to track Arctic storms, whereas, the storm frequency is found to be higher in winter than summer when using 850 hPa relative vorticity to track storms, based on using the same storm tracking algorithm. It is also found that there are no significant trends in Arctic storm characteristics between 1980 and 2017. Given the sparsity of observations in the Arctic, it might be expected that there are large differences in Arctic storm characteristics between the reanalysis datasets. Though, some similar Arctic storm characteristics are found between the reanalysis datasets, it is found that the differences in Arctic storm characteristics between the reanalysis datasets are generally higher in winter than in summer. Overall, the results show that there are differences in Arctic storm characteristics between reanalysis datasets, but even larger differences can arise between using 850 hPa relative vorticity or mean sea level pressure as the storm tracking variable, which adds to the uncertainty associated with current Arctic storm characteristics

    International Law and Arctic Shipping

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    The Arctic Ocean is gradually experiencing the effects of globalisation as a result of climate change, ice melt, and the emergence of a range of shipping activity in the sub-Arctic, along the Arctic coast, and within the central Arctic Ocean. While international law has been prominent in any consideration to date of the shipping issues associated with the Northern Sea Route (Northeast Passage) and the Northwest Passage, the development of trans-Arctic shipping and associated new shipping routes throughout various parts of the Arctic have the potential to raise a series of new Arctic international legal issues which have never before considered in an Arctic context. This paper will assess those issues with reference to how the navigational regime under the 1982 United Nations Convention on the Law of the Sea applies in the Arctic and how the freedom of navigation exercised through international straits and the high seas may in an Arctic setting need to be balanced against the legitimate rights and interests of the Arctic littoral states, including indigenous peoples. Solutions to these issues consistent with contemporary international law will be considered, including whether there may be a need to develop distinctive responses to some of these questions

    Arctic air pollution: Challenges and opportunities for the next decade

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

    Utilizing Colored Dissolved Organic Matter to Derive Dissolved Black Carbon Export by Arctic Rivers

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    Wildfires have produced black carbon (BC) since land plants emerged. Condensed aromatic compounds, a form of BC, have accumulated to become a major component of the soil carbon pool. Condensed aromatics leach from soils into rivers, where they are termed dissolved black carbon (DBC). The transport of DBC by rivers to the sea is a major term in the global carbon and BC cycles. To estimate Arctic river DBC export, 25 samples collected from the six largest Arctic rivers (Kolyma, Lena, Mackenzie, Ob’, Yenisey and Yukon) were analyzed for dissolved organic carbon (DOC), colored dissolved organic matter (CDOM), and DBC. A simple, linear regression between DOC and DBC indicated that DBC accounted for 8.9 ± 0.3% DOC exported by Arctic rivers. To improve upon this estimate, an optical proxy for DBC was developed based upon the linear correlation between DBC concentrations and CDOM light absorption coefficients at 254 nm (a254). Relatively easy to measure a254 values were determined for 410 Arctic river samples between 2004 and 2010. Each of these a254 values was converted to a DBC concentration based upon the linear correlation, providing an extended record of DBC concentration. The extended DBC record was coupled with daily discharge data from the six rivers to estimate riverine DBC loads using the LOADEST modeling program. The six rivers studied cover 53% of the pan-Arctic watershed and exported 1.5 ± 0.1 million tons of DBC per year. Scaling up to the full area of the pan-Arctic watershed, we estimate that Arctic rivers carry 2.8 ± 0.3 million tons of DBC from land to the Arctic Ocean each year. This equates to ~8% of Arctic river DOC export, slightly less than indicated by the simpler DBC vs DOC correlation-based estimate. Riverine discharge is predicted to increase in a warmer Arctic. DBC export was positively correlated with river runoff, suggesting that the export of soil BC to the Arctic Ocean is likely to increase as the Arctic warms

    Arctic HYCOS – 1st Workshop on Improved Monitoring, Accuracy and Data Availability in the Arctic Drainage Basin: Meeting Summary Report and Implementation Plan

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    The World Hydrological Cycle Observing System (WHYCOS) is a global programme, developed in response to the scarcity or absence of accurate, timely and accessible data and information in real or near real time on freshwater resources in many parts of the world. The programme is implemented through various components (HYCOSs) at the regional and/or basin scale. It is guided by the WHYCOS International Advisory Group (WIAG). The Arctic-HYCOS program is being promoted through this Workshop. For more information on the WHYCOS, please see http://www.whycos.org/cms/. The main goal of the Arctic-HYCOS program is to improve monitoring, data accuracy, availability and dissemination of information in the pan-arctic drainage basin. This project is science-driven and is aimed at monitoring freshwater fluxes and pollutants into the Arctic Ocean with the objective of improving climate predictions in the Northern Hemisphere and assessing the pollution of the Arctic coastal areas and the open Arctic Ocean. Arctic-HYCOS is currently organized along three main activities. 1. Develop and optimal design fro hydro-meteorological monitoring networks to capture the essential variability of the Arctic hydrological system and to enable accurate and efficient assessment of change 2. Estimate uncertainty of available in situ and possible remote sensing data including analysis of accuracy and systematic errors of new observation technology 3. Develop an integrated pan-arctic data consolidation and analysis system for the water cycle uniting data from various in-situ and other sources

    Beryllium 7 and Lead 210 in the western hemisphere Arctic atmosphere: Observations from three recent aircraft-based sampling programs

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    Concentrations of the natural radionuclides 7Be and 210Pb were determined in aerosol samples collected in the western hemisphere Arctic during the recent NOAA Arctic Gas and Aerosol Sampling Program (AGASP 3) and NASA Global Tropospheric Experiment/Arctic Boundary Layer Expeditions (GTE/ABLE 3A and ABLE 3B) missions. Beryllium 7 showed a free tropospheric concentration maximum between 4 and 5 km in the summer of 1990. Previous 7Be data obtained in the late 1950s and early 1960s also indicated a similar vertical distribution of 7Be near 70°N. Injection of stratospheric air through tropopause folds associated with the Arctic jet near 70°N appears to explain the presence of a layer of air near 4–5 km in the high Arctic free troposphere with elevated 7Be concentrations. The vertical distribution of 210Pb showed a distinct difference between the high-Arctic and sub-Arctic in the summer of 1988. At latitudes greater than 65°N, 210Pb concentrations at 3–6 km were elevated compared to those below 1 km. The reverse of this trend was observed near 60°N. These same vertical distributions were also apparent in aerosol SO42−, determined in separate aerosol samples collected on the same flights (Talbot et al., this issue). The results for 210Pb suggest that some of the difference between the summer troposphere in the high- and sub-Arctic is also due to enhanced stratosphere-troposphere exchange in the vicinity of the Arctic jet. These observations, and other findings from ABLE 3A presented in this issue, suggest that for some species the stratosphere may be a principal source influencing their distribution in the Arctic summer troposphere. For example, intrusions of stratospheric air constitute the dominant source term for tropospheric budgets of 7Be and ozone, and may be important in the 210Pb, SO42−, and NOybudgets. Further investigation, including determination of detailed 7Be and 210Pb distributions, is needed to quantify the stratospheric impact on the chemistry of the Arctic troposphere during the summer

    Preparing for a Northwest Passage: A Workshop on the Role of New England in Navigating the New Arctic

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    Preparing for a Northwest Passage: A Workshop on the Role of New England in Navigating the New Arctic (March 25 - 27, 2018 -- The University of New Hampshire) paired two of NSF\u27s 10 Big Ideas: Navigating the New Arctic and Growing Convergence Research at NSF. During this event, participants assessed economic, environmental, and social impacts of Arctic change on New England and established convergence research initiatives to prepare for, adapt to, and respond to these effects. Shipping routes through an ice-free Northwest Passage in combination with modifications to ocean circulation and regional climate patterns linked to Arctic ice melt will affect trade, fisheries, tourism, coastal ecology, air and water quality, animal migration, and demographics not only in the Arctic but also in lower latitude coastal regions such as New England. With profound changes on the horizon, this is a critical opportunity for New England to prepare for uncertain yet inevitable economic and environmental impacts of Arctic change

    Microsatellite loci among Alaskan rabies hosts: Arctic and red fox

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    Little is known about the population dynamics between Arctic and red foxes in Alaska and consequences for rabies ecology. Both species carry different variants of rabies and inhabit different environments. As the global warming trends progress, the Arctic and red fox will have increased habitat overlap due to northward range expansion of the red fox into the historic habitat of the Arctic fox. Hypothesis: global warming trends will significantly influence the disease dynamics between red and Arctic foxes as well as their roles in disease dynamics in the far North. In order to better survey the movement of the variants of rabies among Arctic and red fox, microsatellites will be used to assess population structure of these host species
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