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Hubert Guillaume, Cheminet Adrien, . (2015). Radiation Effects Investigations Based on Atmospheric Radiation Model (ATMORAD) Considering GEANT4 Simulations of Extensive Air Showers and Solar Modulation Potential.
. Radiat. Res., 184(1), 83–94.
Abstract: The natural radiative atmospheric environment is composed of secondary cosmic rays produced when primary cosmic rays hit the atmosphere. Understanding atmospheric radiations and their dynamics is essential for evaluating single event effects, so that radiation risks in aviation and the space environment (space weather) can be assessed. In this article, we present an atmospheric radiation model, named ATMORAD (Atmospheric Radiation), which is based on GEANT4 simulations of extensive air showers according to primary spectra that depend only on the solar modulation potential (force-field approximation). Based on neutron spectrometry, solar modulation potential can be deduced using neutron spectrometer measurements and ATMORAD. Some comparisons between our methodology and standard approaches or measurements are also discussed. This work demonstrates the potential for using simulations of extensive air showers and neutron spectroscopy to monitor solar activity.
Keywords: Atmosphere, Computer Simulation, Cosmic Radiation, Models, Theoretical, Neutrons, Solar Activity,
Programme: 1112
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Raynaud D., Barnola J.M., Chappellaz J., Zardini D., Jouzel J. & Lorius C. (1992). Glacial-interglacial evolution of greenhouse gases as inferred from ice core analysis:a review of recent results. Quat Sci Rev, 11, 381–386.
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. (2000). The ice record of greenhouse gases: a view in the context of future changes. Quat Sci Rev, 19.
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Huybrechts P. (2002). Sea-level changes at the LGM from ice-dynamic reconstructions of the Greenland and Antarctic ice sheets during the glacial cycles. Quat Sci Rev, 21(13), 203–231.
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Jouzel J., Hoffmann G., Koster R.D. & Masson V. (1999). Water isotopes in precipitation:data/model comparison for present-day and past climates. Quat Sci Rev, 19(1-5), 363–379.
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Landais A., Barnola J.M., Awamura K., Caillon N., Delmotte M., Van Ommen T., Dreyfus G., Jouzel J., Masson-Delmotte V., Minster B., Freitag J., Leuenberger M., Schwander J., Huber C., Etheridge D. & Morgan V. (2006). Firn-air d15N in modern polar sites and glacial-interglacial ice: a model-data mismatch during glacial periods in Antarctica? Quat Sci Rev, 25(1-2), 49–62.
Abstract: The phase lag between atmospheric composition (air bubbles) and temperature (water isotopes) can be quantified from ice cores provided that the age difference between entrapped air and the surrounding air can be correctly estimated. This difference depends on the lock-in depth (LID), when air no longer mixes with the atmosphere. The LID can be estimated from firnification models or from the air isotopic composition (?15N and ?40Ar). Both methods give consistent results for Greenland and one coastal site in Antarctica (Byrd). New firn measurements in Greenland (NorthGRIP) and Antarctica (Berkner Island, BAS depot, Dome C) confirm that firnification models correctly reproduce the present LID over a large range of surface conditions. However, a systematic mismatch is observed for the Last Glacial Maximum (LGM) in East Antarctic sites (Vostok, Dome C, Dome F) questioning the model's validity. Here we use new ?15N measurements from two coastal Antarctic sites (Kohnen Station and Law Dome) providing depth estimates again distinct from firnification model calculations. We show that this discrepancy can be resolved by revising the estimate of past accumulation rates. ?15N measurements can therefore help to constrain past accumulation rate and improve ice core dating.
Programme: 960
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. (2007). The GRIP deuterium-excess record. Quat Sci Rev, 26, 1–17.
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Goni MFS, Landais A, Fletcher WJ, Naughton F, Desprat S, Duprat J. (2008). Contrasting impacts of Dansgaard-Oeschger events over a western European latitudinal transect modulated by orbital parameters. Quat Sci Rev, 27, 1136–1151.
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. (2009). Timing of massive 'Fleuve Manche' discharges over the last 350 kyr: insights into the European Ice Sheet oscillations and the European drainage network from MIS 10 to 2. Quat Sci Rev, 28, 1238–1256.
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. (2009). Sea ice variations in the central Canadian Arctic Archipelago during the Holocene. Quat Sci Rev, 28, 1354–1366.
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