Landais, A.; Masson-Delmotte, V.; Combourieu Nebout, N.; Jouzel, J.; Blunier, T.; Leuenberger, M.; Dahl-Jensen, D.; Johnsen, S. (2007). Millenial scale variations of the isotopic composition of atmospheric oxygen over Marine Isotopic Stage 4. Earth Planet. Sci. Lett., 258(1-2), 101–113.
Abstract: During rapid events of the last glacial period (DO events), dramatic changes are recorded at high and low latitudes. Without a precise common timescale, links between changes in Greenland temperature and changes in biosphere productivity, hydrology regimes and sea level are difficult to establish. The composition of atmospheric oxygen (?18Oatm) is influenced by global sea level changes, the global hydrologic cycle and the biosphere productivity. Since ?18Oatm is measured in ice cores it gives the opportunity to investigate the underlying processes with no timescale uncertainty. Here, we present the first high resolution (50 yrs) record of the isotopic composition of atmospheric oxygen (?18Oatm) measured in the air trapped in a Greenland ice core (NorthGRIP). Our record covers a sequence of DO events (18-19-20) corresponding to the Marine Isotopic Stage 4, ˜ 75 to 60 ka ago. Our measurements reveal rapid changes of ?18Oatm associated with the DO events. With a few additional measurements of the third isotope of oxygen (17O) during the DO event 19, we exclude the hypothesis that sea level changes are responsible for the isotopic variations. They originate more likely from large changes in relative humidity and latitudinal repartition of the continental vegetation over the DO events.
Programme: 458
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Masson, S., Klein, K.-L., Buetikofer, R., Flueckiger, E., Kurt, V., Yushkov B. & Krucker, S. (2009). Acceleration of Relativistic Protons during the 20 January 2005 Flare and CME. SOLAR PHYSICS, 257, 305.
Abstract: The origin of relativistic solar protons during large flare/CME events has not been uniquely identified so far. We perform a detailed comparative analysis of the time profiles of relativistic protons detected by the worldwide network of neutron monitors at Earth with electromagnetic signatures of particle acceleration in the solar corona during the large particle event of 20 January 2005. The intensity – time profile of the relativistic protons derived from the neutron monitor data indicates two successive peaks. We show that microwave, hard X-ray, and ! -ray emissions display several episodes of particle acceleration within the impulsive flare phase. The first relativistic protons detected at Earth are accelerated together with relativistic electrons and with protons that produce pion-decay ! rays during the second episode. The second peak in the relativistic proton profile at Earth is accompanied by new signatures of particle acceleration in the corona within !1R" above the photosphere, revealed by hard X-ray and microwave emissions of low intensity and by the renewed radio emission of electron beams and of a coronal shock wave. We discuss the observations in terms of different scenarios of particle acceleration in the corona.
Programme: 227
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Wittlinger G. & Farra V. (2007). Converted waves reveal a thick and layered tectosphere beneath the Kalahari super-craton. Earth Planet. Sci. Lett., 254, 404–415.
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Danesi S., S. Bannister and A. Morelli. (2007). Repeating earthquakes from rupture of an asperity under an Antarctic outlet glacier. Earth Planet. Sci. Lett., 253, 151–158.
Abstract: doi: 10.1016/j.epsl.2006.10.023, Vol. 253
(1-2)
Programme: 906
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Fourré E., P. Jean Baptiste, A. Dapoigny, D. Baumier, J.R. Petit, J. Jouzel:. (2006). Past and recent tritium levels in Arctic and Antarctic polar caps. Earth Planet. Sci. Lett., 245, 56–64.
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Démoulin, P.; Klein, K.-L.; Goff, C.; van Driel-Gesztelyi, L.; Culhane, J.; Mandrini, C.; Matthews, S.; Harra, L. (2007). Decametric N Burst: A Consequence of the Interaction of Two Coronal Mass Ejections. Solar physics, 240(2), 301–313.
Abstract: Abstract Radio emissions of electron beams in the solar corona and interplanetary space are tracers of the underlying magnetic configuration and of its evolution. We analyse radio observations from the Culgoora and WIND/WAVES spectrographs, in combination with SOHO/LASCO and SOHO/MDI data, to understand the origin of a type N burst originating from NOAA AR 10540 on January 20, 2004, and its relationship with type II and type III emissions. All bursts are related to the flares and the CME analysed in a previous paper (Goff et al., 2007). A very unusual feature of this event was a decametric type N burst, where a type III-like burst, drifting towards low frequencies (negative drift), changes drift first to positive, then again to negative. At metre wavelengths, i.e., heliocentric distances ?1.5R ?, these bursts are ascribed to electron beams bouncing in a closed loop. Neither U nor N bursts are expected at decametric wavelengths because closed quasi-static loops are not thought to extend to distances ?1.5R ?. We take the opportunity of the good multi-instrument coverage of this event to analyse the origin of type N bursts in the high corona. Reconnection of the expanding ejecta with the magnetic structure of a previous CME, launched about 8 hours earlier, injects electrons in the same manner as with type III bursts but into open field lines having a local dip and apex. The latter shape was created by magnetic reconnection between the expanding CME and neighbouring (open) streamer field lines. This particular flux tube shape in the high corona, between 5R ? and 10R ?, explains the observed type N burst. Since the required magnetic configuration is only a transient phenomenon formed by reconnection, severe timing and topological constraints are present to form the observed decametric N burst. They are therefore expected to be rare features.
Programme: 227
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Ayllon F., Davaine P., Beall E., Martinez J.L. & Garcia-Vazquez E. (2004). Bottlenecks and genetic changes in Atlantic salmon (Salmo salar L.) stocks introduced in the Subantarctic Kerguelen Islands. Aquaculture, 237(1-4), 103–116.
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Cherel Y., Gilles J., Handrich Y. & Le Maho Y. (1994). Nutrient reserve dynamics and energetics during long-term fasting in the king penguin (Aptenidytes patagonicus). J. Zool. (Lond.), 234.
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Challet E., Bost C.A., Handrich Y., Gendner J.P. & Le Maho Y. (1994). Behavioural time budget of breeding king penguins (Aptenodytes patagonica). J. Zool. (Lond.), 233(4), 669–681.
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Ayllon F., Martinez J.L., Davaine P., Beall E. & Garcia-Vazquez E. (2004). Interspecific hybridization between Atlantic salmon and brown trout introduced in the subantarctic Kerguelen Islands. Aquaculture, 230(1-4), 81–88.
Abstract: SALMOPOP
Programme: 365
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