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Frezzotti M., M. Pourchet, O. Flora, S. Gandolfi, M. Gay, S. Urbini, C. Vincent, S. Becagli, R. Gragnani, M. Proposito, M. Severi, R. Traversi, R. Udisti, M. Fily. (2005). Spatial and temporal variability of snow accumulation in East Antarctica from traverse data. Journal of glaciology, 51(172), 113–124.
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Haan D. & Raynaud D. (1998). Ice core record of CO variations during the last two millennia: atmospheric implications and chemical interactions within the Greenland ice. Tellus series a-dynamic meteorology and oceanography, 50B(3), 253–262.
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Genthon, C.; Krinner, G.; Castebrunet, H. (2009). Antarctic precipitation and climate-change predictions: horizontal resolution and margin vs plateau issues. Annals of glaciology, 50, 55–60.
Abstract: All climate models participating in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, as made available by the Program for Climate Model Diagnosis and Intercomparison (PCMDI) as the Coupled Model Intercomparison Project 3 (CMIP3) archive, predict a significant surface warming of Antarctica by the end of the 21st century under a moderate (SRESA1B) greenhouse-gas scenario. All models but one predict a concurrent precipitation increase but with a large scatter of results. The models with finer horizontal resolution tend to predict a larger precipitation increase. Because modeled Antarctic surface mass balance is known to be sensitive to horizontal resolution, extrapolating predictions from the different models with respect to model resolution may provide simple yet better multi-model estimates of Antarctic precipitation change than mere averaging or even more complex approaches. Using such extrapolation, a conservative estimate of the predicted precipitation increase at the end of the 21st century is +30 kg m−2a−1 on the grounded ice sheet, corresponding to a >1 mm a−1 sea-level rise. About three-quarters of this rise originates from the marginal regions of the Antarctic ice sheet with surface elevation below 2250 m. This is where field programs are most urgently needed to better understand and monitor accumulation at the surface of Antarctica, and to improve and verify prediction models.
Programme: 411
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GENTHON C. , MAGAND O. , KRINNER G. , FILY M. (2009). Do climate models underestimate snow accumulation on the Antarctic plateau? A re-evaluation of/from in situ observations in East Wilkes and Victoria Lands. Annals of glaciology, 50, 61–65.
Abstract: It has been suggested that meteorological and climate models underestimate snow accumulation on the Antarctic plateau, because accumulation (or surface mass balance (SMB)) is dominated by clear-sky precipitation while this process is not properly taken into account in the models. Here, we show that differences between model and field SMB data are much reduced when the in situ SMB reports used to evaluate the models are filtered through quality-control criteria and less reliable reports are subsequently left out. We thus argue that, although not necessarily unsupported, model biases and their interpretations in terms of clear-sky vs synoptic precipitation on the Antarctic plateau may have been overstated in the past. To avoid such misleading issues, it is important that in situ SMB reports of insufficient or unassessed reliability are discarded, even at the cost of a strong reduction in spatial sampling and coverage.
Keywords: polar regions ; Antarctica ; Diamond dust ; Victoria Land ; Wilkes Land ; ground truth ; Observation data ; algorithm performance ; Climate models ; accumulation ; Clear sky ; atmospheric precipitation ; mass balance ; Glacier balance ; ice sheets ; Polar region
Programme: 411;454
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Leblond S., S. Gombert, J.L. Colin, R. Losno and C. Rausch de Traubenberg. (2004). Biological and temporal variations of trace element concentrations in the moss species Scleropodium purum (Hedw.) Limpr. Journal of atmospheric chemistry, 49, 107–122.
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Scoates J., Weis D., Franssens M., Mattielli N., Annell H., Frey F.A., Nycolaysen K., and Giret A. (2008). The Val Gabbro Plutonic Suite: A Sub-volcanic Intrusion Emplaced at the End of Flood Basalt Volcanism on the Kerguelen Archipelago. Journal of petrology, 49, 79–105.
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Simon, N.S.C.; Neumann, E.-R.; Bonadiman, C.; Coltorti, M.; Delpech, G.; Gregoire, M.; Widom, E. (2008). Ultra-refractory Domains in the Oceanic Mantle Lithosphere Sampled as Mantle Xenoliths at Ocean Islands. Journal of petrology, 49(6), 1223–1251.
Abstract: Many peridotite xenoliths sampled at ocean islands appear to have strongly refractory major element and modal compositions. To better constrain the chemistry, abundance and origin of these ultra-refractory rocks we compiled a large number of data for xenoliths from nine groups of ocean islands. The xenoliths were filtered petrographically for signs of melt infiltration and modal metasomatism, and the samples affected by these processes were excluded. The xenolith suites from most ocean islands are dominated by ultra-refractory harzburgites. Exceptions are the Hawaii and Tahiti peridotites, which are more fertile and contain primary clinopyroxene, and the Cape Verde suite, which contains both ultra-refractory and more fertile xenoliths. Ultra-refractory harzburgites are characterized by the absence of primary clinopyroxene, low whole-rock Al2O3, CaO, FeO/MgO and heavy rare earth element (HREE) concentrations, low Al2O3 in orthopyroxene (generally < 3 wt %), high Cr-number in spinel (0{middle dot}3-0{middle dot}8) and high forsterite contents in olivine (averages > 91{middle dot}5). They are therefore on average significantly more refractory than peridotites dredged and drilled from mid-ocean ridges and fracture zones. Moreover, their compositions resemble those of oceanic forearc peridotites. The formation of ultra-refractory ocean island harzburgites requires potential temperatures above those normally observed at modern mid-ocean ridges, and/or fluid fluxed conditions. Some ultra-refractory ocean island harzburgites give high Os model ages (up to 3300 Ma), showing that their formation significantly pre-dates the oceanic crust in the area. A genetic relationship with the host plume is considered unlikely based on textural observations, equilibration temperatures and pressures, inferred physical properties, and the long-term depleted Os and Sr isotope compositions of some of the harzburgites. Although we do not exclude the possibility that some ultra-refractory ocean island harzburgites have formed at mid-ocean ridges, we favor a model in which they formed in a process spatially and temporally unrelated to the formation of the oceanic plate and the host plume. As a result of their whole-rock compositions, ultra-refractory harzburgites have a very high solidus temperature at a given pressure, low densities and very high viscosities, and will tend to accumulate at the top of the convecting mantle. They may be preserved as fragments in the convecting mantle over long periods of time and be preferentially incorporated into newly formed lithosphere.
Programme: 444
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Schlosser E., Van Lipzig N. & Oerter H. (2002). Temporal variability of accumulation at Neumayer Station, Antarctica, from stake array measurements and a regional atmospheric model. Journal of glaciology, 48(160), 87–94.
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Gay M., Fily M., Genthon C., Frezzotti M., Oerter H. & Winther J.G. (2002). Snow grain-size measurements in Antarctica. Journal of glaciology, 48(163), 527–535.
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Delille D., Coulon F. & Pelletier E. (2007). The influence of temperature on bacterial assemblages during bioremediation of a diesel fuel contaminated subAntarctic soil. Cold regions science and technology, 48, 74–83.
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