Masson-Delmotte, V.; Hou, S.; Ekaykin, A.; Jouzel, J.; Aristarain, A.; Bernardo, R.T.; Bromwich, D.; Cattani, O.; Delmotte, M.; Falourd, S.; Frezzotti, M.; Gallée, H.; Genoni, L.; Isaksson, E.; Landais, A.; Helsen, M.M.; Hoffmann, G.; Lopez, J.; Morgan, V.; Motoyama, H.; Noone, D.; Oerter, H.; Petit, J.R.; Royer, A.; Uemura, R.; Schmidt, G.A.; Schlosser, E.; Simões, J.C.; Steig, E.J.; Stenni, B.; Stievenard, M.; van den Broeke, M.R.; van de Wal, R.S.W.; van de Berg, W.J.; Vimeux, F.; White, J.W.C. (2008). A Review of Antarctic Surface Snow Isotopic Composition: Observations, Atmospheric Circulation, and Isotopic Modeling*. Journal of climate, 21(13), 3359–3387.
Abstract: A database of surface Antarctic snow isotopic composition is constructed using available measurements, with an estimate of data quality and local variability. Although more than 1000 locations are documented, the spatial coverage remains uneven with a majority of sites located in specific areas of East Antarctica. The database is used to analyze the spatial variations in snow isotopic composition with respect to geographical characteristics (elevation, distance to the coast) and climatic features (temperature, accumulation) and with a focus on deuterium excess. The capacity of theoretical isotopic, regional, and general circulation atmospheric models (including “isotopic” models) to reproduce the observed features and assess the role of moisture advection in spatial deuterium excess fluctuations is analyzed.
Keywords: Snow; Antarctica; Atmospheric circulation; Isotopic analysis; In situ observations
Programme: 355;454
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Xu, G.; Frey, F.A.; Weis, D.; Scoates, J.S.; Giret, A. (2007). Flood basalts from Mt. Capitole in the central Kerguelen Archipelago: Insights into the growth of the archipelago and source components contributing to plume-related volcanism. Geochem. Geophys. Geosyst., 8.
Abstract: The Kerguelen Archipelago, constructed on the submarine Northern Kerguelen Plateau, is attributed to Cenozoic volcanism arising from the Kerguelen hot spot. Geochemical studies of 325 to 1000 m thick lava sections of the ?30 to 25 Ma flood basalt forming the bulk of the archipelago show a temporal change from older tholeiitic basalt to younger slightly alkalic basalt. This compositional transition is expressed in a 630 m lava section at Mt. Capitole where the lava sequence is lowermost tholeiitic basalt overlain by slightly alkalic basalt overlain by plagioclase-rich cumulates that are mixtures of plagioclase-phyric basalt and more evolved magmas. During growth of the archipelago, magma supply from the hot spot was variable and at times sufficiently low to enable extensive crystal fractionation; e.g., at Mt. Capitole and nearby Mt. Tourmente only 10 of 120 lava flows have >6 wt% MgO. On the basis of this study and previous isotopic data for the ?34 Ma submarine lavas erupted on the Northern Kerguelen Plateau, other flood basalt sections in the Kerguelen Archipelago, and younger lavas erupted in the archipelago and at Heard Island, there is significant Sr, Nd, Hf, and Pb isotopic heterogeneity that can be explained by two stages of mixing. The first mixing event, best shown by the submarine lavas, is between components that are related to Indian Ocean mid-ocean ridge basalt (MORB) and the Kerguelen hot spot. From ?34 Ma to <1 Ma, on average the proportion of the MORB-related component decreased. Subsequently, a second mixing process involved addition of a component with relatively high 87Sr/86Sr (>0.7060) and low 143Nd/144Nd (<0.5125) and 176Hf/177Hf (<0.2827) and nonradiogenic Pb isotope ratios (<17.9 for 206Pb/204Pb). We infer that this component was lower continental crust.
Keywords: Kerguelen mantle plume; Kerguelen Archipelago; Mt. Capitole; lower continental crust; Sr; Nd; Hf; Pb isotopic ratios; 1037 Geochemistry: Magma genesis and partial melting; 1038 Geochemistry: Mantle processes; 1065 Geochemistry: Major and trace element geochemistry
Programme: 444
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Fahlman, A.; Handrich, Y.; Woakes, A.J.; Bost, C.-A.; Holder, R.; Duchamp, C.; Butler, P.J. (2004). Effect of fasting on the VO2-fh relationship in king penguins, Aptenodytes patagonicus. Am. J. Physiol. Regul. Integr. Comp. Physiol., 287(4), R870–877.
Abstract: King penguins (Aptenodytes patagonicus) may fast for up to 30 days during their breeding period. As such extended fasting may affect the relationship between the rate of O2 consumption (O2) and heart rate (fH), five male king penguins were exercised at various speeds on repeated occasions during a fasting period of 24-31 days. In addition, O2 and fH were measured in the same animals during rest in cold air and water (4{degrees}C). O2 and fH at rest and O2 during exercise decreased with fasting. There was a significant relation between O2 and fH (r2 = 0.56) that was improved by including speed, body mass (Mb), number of days fasting (t), and a cross term between fH and t (r2 = 0.92). It was concluded that there was a significant change in the O2-fH relationship with fasting during exercise. As t is measurable in the field and was shown to be significant and, therefore, a practical covariate, a regression equation for use when birds are ashore was obtained by removing speed and Mb. When this equation was used, predicted O2 was in good agreement with the observed data, with an overall error of 3.0%. There was no change in the O2-fH relationship in penguins at rest in water.
Programme: 131;137;394
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Nishitani, N.; Ogawa, T.; Sato, N.; Yamagishi, H.; Pinnock, M.; Villain, J.-P.; Sofko, G.; Troshichev, O. (2002). A study of the dusk convection cell's response to an IMF southward turning. J. Geophys. Res., 107.
Abstract: One example of the response of ionospheric convection and the polar cap boundary to a sudden change in the interplanetary magnetic field (IMF) orientation has been studied by using ground magnetometers, the Super Dual Auroral Radar Network (SuperDARN), and Defense Meteorological Satellite Program (DMSP) particle detectors when the IMF suddenly changed from northward (+6 nT) to strongly southward (?19 nT) at 1716 UT on 5 September 1995. The Bz component was fairly constant for ?2 hours before and ?25 min after the sudden IMF change. The convection flow changed almost simultaneously over a global extent. This initial change of the convection pattern can be characterized by a sudden formation of a large flow vortex in the afternoon sector. This agrees with the earlier findings by Ruohoniemi and Greenwald [1998] and Ridley et al. [1998]. On the other hand, the response of the polar cap boundary (or its proxy) is more complicated. The Saskatoon radar, located in the late morning sector, observed an equatorward shift of the cusp scatter region simultaneously with the initial response of the convection flows. The DMSP particle data also showed a simultaneous equatorward expansion of the auroral oval in the 2100 magnetic local time (MLT) sector. The radar and particle data indicate the immediate equatorward expansion of the precipitation regions in the noon and premidnight sectors. About 10–20 min after the initial change, there were changes observed in the dusk region, namely, an equatorward expansion of the current reversal boundary observed by the Greenland magnetometer chain in the dusk sector between 1740 and 1750 UT and an equatorward expansion of the convection reversal boundary detected by the Stokkseyri, Halley, and Syowa radars. The delayed responses were observed 18-8 min before a substorm onset was recorded at midlatitude stations at 1756 UT. These observations indicate that there were two kinds of ionospheric responses to the southward turning of the IMF; the first response is the formation of the convection vortex and the equatorward shift of the polar cap boundary at noon and at ?2100 MLT, and the second response is the equatorward expansion of the convection reversal boundary in the dusk sector. We make the case that the first response is associated with the propagation of magnetosonic waves and that the second response is consistent with the Cowley and Lockwood [1992] picture of the redistribution of the newly created open flux in the polar cap region.
Keywords: 2463 Ionosphere: Plasma convection; 2431 Ionosphere: Ionosphere/magnetosphere interactions; 2437 Ionosphere: Ionospheric dynamics; 2784 Magnetospheric Physics: Solar wind/magnetosphere interactions
Programme: 312;911
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Le Quere, C.; Rodenbeck, C.; Buitenhuis, E.T.; Conway, T.J.; Langenfelds, R.; Gomez, A.; Labuschagne, C.; Ramonet, M.; Nakazawa, T.; Metzl, N.; Gillett, N.; Heimann, M. (2007). Saturation of the Southern Ocean CO2 Sink Due to Recent Climate Change. Bachelor's thesis, , .
Abstract: Based on observed atmospheric CO2 concentration and an inverse method, we estimate that the Southern Ocean sink of CO2 has weakened between 1981 and 2004 by 0.08 PgC/y per decade relative to the trend expected from the large increase in atmospheric CO2. This weakening is attributed to the observed increase in Southern Ocean winds resulting from human activities and projected to continue in the future. Consequences include a reduction in the efficiency of the Southern Ocean sink of CO2 in the short term (~25 years) and possibly a higher level of stabilization of atmospheric CO2 on a multicentury time scale.
Programme: 416;439
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Halsey, L.G. Butler, P.J., Fahlman, A., Bost, C.-A., Woakes, A.J., Handrich, Y. (2008). Modelling the marine resources required to raise a king penguin chick in differing environments: an energetics approach. Physiol. Biochem. Zool., 81(6), 856–867.
Abstract: Accurate estimates of penguin energetics would represent an important contribution to our understanding of the trophodynamics of the Southern Ocean ecosystem and our ability to predict effects of environmental change on these species. We used the heart rate–rate of oxygen consumption technique to estimate rate of energy expenditure in adult king penguins raising a chick, in combination with data from the literature on changes in adult mass, chick energy requirements, and prey energy density. Our model estimated a variety of energetic costs and quantities of prey consumption related to raising a king penguin chick during the austral summer. The total energy requirements of a king penguin chick at the Crozet Archipelago from hatching until reaching a mass of 8 kg 90 d later is 271 MJ, representing the consumption of 38.4 kg of myctophid fish. A successfully breeding male requires 0.78 kg d-1 of fish during the entirety of the incubation period and 1.14 kg d-1 during the subsequent 90 d of chick rearing. Assuming the same energy requirements for females, the estimated 580,000 pairs of king penguins that breed successfully at Crozet each year, together with their chicks, consume a total of around 190,000 tons of fish during the incubation and summer rearing periods combined. If, due to depletion of fish stocks, the diet of breeders and chicks during the summer becomes identical to the typical diet of adults during the austral winter, the mass of prey required by both adults and chicks combined (where the chick still reaches 8 kg after 90 d) would increase by more than 25%.
Programme: 394
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Charrier, Isabelle. (2009). Mother-Young Vocal Recognition in Pinnipeds: review and perspectives..
Abstract: Communication Orale présentée au 10th Internal Mammalogy Congress, Mendoza, Argentine, 9-14 aout 2009.
Programme: 450
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Favier V. and C. Genthon. (2009). Rapport de mission glacioclim.
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Agosta C., C. Genthon, V. Favier, G. Krinner, H. Gallée, G. Picard, D. Six. (2009). Spatial distribution of accumulation in the Adélie Land – Comparison of the Antarctic GLACIOCLIM-SAMBA observation data with remote sensing techniques and high-resolution climate models.
Abstract: MOCA-09, the IAMAS-IAPSO-IACS 2009 Joint Assembly, Montréal, Canada, July 19-29, 2009.
Programme: 411
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Agosta C., C. Genthon, V. Favier, D. Six. (2008). Transect GLACIOCLIM-SAMBA : observation et modélisation du Bilan de Masse de Surface sur la zone de transition côte-plateau Antarctique.
Abstract: Comité National Français des Recherches Arctique et Antarctique; 5èmes Journées Scientifiques, Paris, 23 et 24 Octobre 2008
Programme: 411
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