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Rémy F. & Ritz C. (2001). Les calottes polaires. Pour la science, 282, 60–67.
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Lorius C. (2003). Effet de serre : les lacunes du savoir et de la perception. Comptes Rendus de Géoscience, 335, 545–549.
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Duval, P.; Montagnat, M. (2002). Comment on “Superplastic deformation of ice: Experimental observations” by D. L. Goldsby and D. L. Kohlstedt. J. Geophys. Res., 107.
Keywords: 1827 Hydrology: Glaciology; 1863 Hydrology: Snow and ice; 3902 Mineral Physics: Creep and deformation; 5120 Physical Properties of Rocks: Plasticity, diffusion, and creep
Programme: 902
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Goujon, C.; Barnola, J.-M.; Ritz, C. (2003). Modeling the densification of polar firn including heat diffusion: Application to close-off characteristics and gas isotopic fractionation for Antarctica and Greenland sites. J. Geophys. Res., 108.
Abstract: Modeling the densification of polar firn is essential to estimate variations of close-off characteristics (density, close-off depth, delta age) in relation with past climate parameters (temperature and accumulation rates). Furthermore, the air composition in the firn is modified by gravitational and thermal fractionation, and stable isotope measurements of permanent gases like nitrogen or argon can provide information on the amplitude of these fractionations. In this work, we propose a new model coupling firn densification and heat diffusion. In addition to the determination of the firn thickness and gas-ice age differences, the model allows a reconstruction of the time evolution of the temperature for different sites in Antarctica (Vostok) and Greenland (GISP2) and therefore the evolution of gravitational and thermal isotopic fractionations in firn. Under present-day conditions, the modeled profiles are in good agreement with the available temperature measurements in firn. For sites with low accumulation rates such as Vostok, the results show the existence of temperature gradients in the firn column even when no rapid climatic changes occur. The comparison of the modeled ?15N results to measurements allows to better constrain the ?18O-temperature relationship, used to infer the surface temperature history, and for GISP2, the model validates the long-term borehole-based temperature.
Keywords: 1827 Hydrology: Glaciology; 1863 Hydrology: Snow and ice; 3344 Meteorology and Atmospheric Dynamics: Paleoclimatology
Programme: 902
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Delmonte B., Petit J.R., Andersen K.K., Basile Doelsch I., Maggi W. & Lipenkov V.Y. (2004). Dust size evidence for opposite regional atmospheric circulation changes over east Antarctica during the last climatic transition. Climate dynamics, 23, 427–438.
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Dumas C. (2002). Modélisation de l'évolution de l'Antarctique depuis le dernier cycle glaciaire-interglaciaire jusqu'au futur : importance relative des différents processus physiques et rôle des données d'entrée..
Abstract: Thèse de l'Université Joseph Fourier Grenoble 1
Programme: 902
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Parrenin F. (2002). Datation glaciologique des forages profonds en Antarctique et modèlisation conceptuelle des paléoclimats : implications pour la théorie astronomique des paléoclimats..
Abstract: Thèse de l'Université Joseph-Fourier Grenoble 1
Programme: 902
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Delmonte B. (2003). Quaternary variations and origin of continental dust in east Antarctica..
Abstract: Thèse de Doctorat de l'Université Joseph-Fourier Grenoble 1
Programme: 902
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Caillon, N.; Jouzel, J.; Severinghaus, J.P.; Chappellaz, J.; Blunier, T. (2003). A novel method to study the phase relationship between Antarctic and Greenland climate. Geophysical research letters, 30.
Abstract: A classical method for understanding the coupling between northern and southern hemispheres during millennial-scale climate events is based on the correlation between Greenland and Antarctic ice core records of atmospheric composition. Here we present a new approach based on the use of a single Antarctic ice core in which measurements of methane concentration and inert gas isotopes place constraints on the timing of a rapid climate change in the North and of its Antarctic counterpart. We applied it to the Marine Isotope Stage (MIS) 5d/c transition early in the last glaciation ?108 ky BP. Our results indicate that the Antarctic temperature increase occurred 2 ky before the methane increase, which is used as a time marker of the warming in the Northern Hemisphere. This result is in agreement with the “bipolar seesaw” mechanism used to explain the phase relationships documented between 23 and 90 ky BP [
Blunier and Brook, 2001].
Keywords: 3344 Meteorology and Atmospheric Dynamics: Paleoclimatology; 4267 Oceanography: General: Paleoceanography; 1827 Hydrology: Glaciology; 4870 Oceanography: Biological and Chemical: Stable isotopes; 1620 Global Change: Climate dynamics
Programme: 902
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Souchez, R.; Petit, J.-R.; Jouzel, J.; Simões, J.; de Angelis, M.; Barkov, N.; Stiévenard, M.; Vimeux, F.; Sleewaegen, S.; Lorrain, R. (2002). Highly deformed basal ice in the Vostok core, Antarctica. Geophysical research letters, 29.
Abstract: Our paper documents the build-up of a highly deformed basal ice layer in the basal part of the Vostok ice core. This is done mainly on the basis of an isotopic composition investigation of the ice. Complex deformation in the lower 228 m of the ice sheet has resulted in folding and intermixing of ice at a submetric scale and, for the upper part of this basal sequence, in interbedding of ice layers from distinct origins at a larger scale. This complex deformation occurred at a temperature largely below the pressure-melting point. The basal ice layer has built upwards and size-selective incorporation of bed material into the ice has taken place. The documentation of this complex basal deformation has implications for the maximum age of ice that will be useful in paleoclimate studies and for ice sheet dynamics.
Keywords: 1040 Geochemistry: Isotopic composition/chemistry; 1827 Hydrology: Glaciology; 4540 Oceanography: Physical: Ice mechanics and air/sea/ice exchange processes; 9310 Information Related to Geographic Region: Antarctica
Programme: 902
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