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Geodetic Results of the Ross Ice Shelf Survey Expeditions, 1962–63 and 1965–66
- Egon Dorrer, Walther Hofmann, Wilfried Seufert
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- Journal:
- Journal of Glaciology / Volume 8 / Issue 52 / 1969
- Published online by Cambridge University Press:
- 30 January 2017, pp. 67-90
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By means of modern geodetic observation techniques the ice movement along an east-west and a north-south profile across the Ross Ice Shelf, Antarctica, was measured during the two Antarctic summers, 1962–63 and 1965–66. 103 markers were placed on the 910 km long traverse. Distances were measured by tellurometer, and traverse angles by a precision theodolite between all consecutive markers, normally 8 to 9 km apart. For this type of observation method, six men distributed into three groups of two men each were necessary.
The main part of the paper deals with data processing and with the computation of the ice movement. As the ice moves, the geometrical configuration of the traverse changes during the epoch of observation. For this “reduction to epoch” problem two methods are described in detail: (1) time reduction of observations, and (2) time reduction of positions. Between the two field journeys, only linear ice movement can be assumed. It is possible, however, to determine acceleration and curvature of the ice flow at all traverse points where the traverse angles differ considerably from 180°.
The result of all computations is the field of velocity vectors along the traverse. Obvious characteristics are the rapid increase of velocity between the McMurdo Ice Shelf and Ross Ice Shelf, the uniform and nearly parallel movement in the middle of the ice shelf (maximum velocity 935 m year−1), the decrease of velocity along the north-south profile, and the systematic increase of divergence of the flow lines towards the ice margins. Careful study of the velocity vector field shows some deviations from an entirely uniform distribution.
16 - Integrating nitrogen fluxes at the European scale
- from Part III - Nitrogen flows and fate at multiple spatial scales
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- By Adrian Leip, European Commission Joint Research Centre, Beat Achermann, Federal Office for the Environment Air Pollution Control, Gilles Billen, University Pierre & Marie Curie, Albert Bleeker, Energy Research Centre of the Netherlands, Alexander F. Bouwman, Netherlands Environmental Assessment Agency, Wim de Vries, Wageningen University and Research Centre, Ulli Dragosits, Centre for Ecology and Hydrology, Ulrike Döring, European Commission Joint Research Centre, Dave Fernall, Food and Rural Affairs Kingspool, Markus Geupel, Federal Environment Agency, Germany, Jürg Herolstab, Penny Johnes, University of Reading, Anne Christine Le Gall, INERIS, France, Suvi Monni, European Commission Joint Research Centre, Rostislav Nevečeřal, Czech Hydrometeorological Institute, Lorenzo Orlandini, European Commission – DG AGRI, Michel Prud'homme, International Fertilizer Industry Association, Hannes I. Reuter, Gisxperts gbr, David Simpson, Norwegian Meteorological Institute, Guenther Seufert, European Commission Joint Research Centre, Till Spranger, Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, Mark A. Sutton, Centre for Ecology and Hydrology, John van Aardenne, European Commission Joint Research Center, Maren Voß, Leibniz-Institute of Baltic Sea Research Warnemuende, Wilfried Winiwarter, International Institute for Applied Systems Analysis
- Edited by Mark A. Sutton, NERC Centre for Ecology and Hydrology, UK, Clare M. Howard, NERC Centre for Ecology and Hydrology, UK, Jan Willem Erisman, Gilles Billen, Albert Bleeker, Peringe Grennfelt, Hans van Grinsven, Bruna Grizzetti
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- Book:
- The European Nitrogen Assessment
- Published online:
- 16 May 2011
- Print publication:
- 14 April 2011, pp 345-376
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Summary
Executive summary
Nature of the problem
Environmental problems related to nitrogen concern all economic sectors and impact all media: atmosphere, pedosphere, hydrosphere and anthroposphere.
Therefore, the integration of fluxes allows an overall coverage of problems related to reactive nitrogen (Nr) in the environment, which is not accessible from sectoral approaches or by focusing on specific media.
Approaches
This chapter presents a set of high resolution maps showing key elements of the N flux budget across Europe, including N2 and Nr fluxes.
Comparative nitrogen budgets are also presented for a range of European countries, highlighting the most efficient strategies for mitigating Nr problems at a national scale. A new European Nitrogen Budget (EU-27) is presented on the basis of state-of-the-art Europe-wide models and databases focusing on different segments of Europe's society.
Key findings
From c. 18 Tg Nr yr−1 input to agriculture in the EU-27, only about 7 Tg Nr yr−1 find their way to the consumer or are further processed by industry.
Some 3.7 Tg Nr yr−1 is released by the burning of fossil fuels in the EU-27, whereby the contribution of the industry and energy sectors is equal to that of the transport sector. More than 8 Tg Nr yr−1 are disposed of to the hydrosphere, while the EU-27 is a net exporter of reactive nitrogen through atmospheric transport of c. 2.3 Tg Nr yr−1.
The largest single sink for Nr appears to be denitrification to N2 in European coastal shelf regions (potentially as large as the input of mineral fertilizer, about 11 Tg N yr–1 for the EU-27); however, this sink is also the most uncertain, because of the uncertainty of Nr import from the open ocean.