Masson-Delmotte, V.; Jouzel, J.; Landais, A.; Stievenard, M.; Johnsen, S.J.; White, J.W.C.; Werner, M.; Sveinbjornsdottir, A.; Fuhrer, K. (2005). GRIP Deuterium Excess Reveals Rapid and Orbital-Scale Changes in Greenland Moisture Origin. Science, 309(5731), 118–121.
Abstract: The Northern Hemisphere hydrological cycle is a key factor coupling ice sheets, ocean circulation, and polar amplification of climate change. Here we present a Northern Hemisphere deuterium excess profile covering one climatic cycle, constructed with the use of {delta}18O and {delta}D Greenland Ice Core Project (GRIP) records. Past changes in Greenland source and site temperatures are quantified with precipitation seasonality taken into account. The imprint of obliquity is evidenced in the site-to-source temperature gradient at orbital scale. At the millennial time scale, GRIP source temperature changes reflect southward shifts of the geographical locations of moisture sources during cold events, and these rapid shifts are associated with large-scale changes in atmospheric circulation.
Programme: 458
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Traversi, R.; Becagli, S.; Castellano, E.; Cerri, O.; Morganti, A.; Severi, M.; Udisti, R. (2009). Study of Dome C site (East Antartica) variability by comparing chemical stratigraphies. Polar Chemistry, 92(1), 7–14.
Abstract: This paper compares chemical stratigraphies from snowpits collected at Dome C (East Antarctica) in order to assess site variability in terms of spatial distribution of chemical markers, annual accumulation rate and chemical species persistence in the snow layers. Since Dome C was chosen for deep drilling down to the bedrock in the framework of EPICA (European Project for Ice Coring in Antarctica), to provide 800kyr of climatic and environmental records, evaluating site variability is fundamental for a reliable interpretation of the deep ice core stratigraphies.
For this purpose, 4 snowpits were dug at Dome C (1997/98, 1998/99, 2000/01 and 2005/06 Antarctic Campaigns) and analysed for cations, inorganic anions and methane sulphonate by ion chromatography. Unlike the first three snowpits, the most recent one was analysed directly in situ, allowing to observe that no chemical contamination or loss due to sample storage and transport to Europe occurs for such a sampling.
Accumulation rate variability was revealed to be around 4% in a common time range (1992-1964) for all snowpits. Intra-snowpit chemical variability was definitely higher than inter-snowpit variability, indicating that the variations observed in the chemical stratigraphies from Dome C can be reliably related to effective changes in source and transport mechanisms of the investigated markers more than to site variability.
Post-depositional phenomena affecting chloride, nitrate and methane sulphonate were studied, revealing a logarithmic decay as a function of depth for Cl- and MSA and an exponential one for NO3-. The relative losses were quantified in the 75-80% range for Cl-, 66-83% for MSA and 89-94% for NO3- and were found to stop around 320, 320 and 60-80cm depth, respectively.
Keywords: Antarctica; Dome C; Snowpit; Chemical analysis; Post-depositional effects
Programme: 1181
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Delmotte, M.; Chappellaz, J.; Brook, E.; Yiou, P.; Barnola, J.M.; Goujon, C.; Raynaud, D.; Lipenkov, V.I. (2004). Atmospheric methane during the last four glacial-interglacial cycles: Rapid changes and their link with Antarctic temperature. J. Geophys. Res., 109.
Keywords: climate; atmospheric methane; ice core; 0325 Atmospheric Composition and Structure: Evolution of the atmosphere; 1610 Global Change: Atmosphere; 1615 Global Change: Biogeochemical processes; 3339 Meteorology and Atmospheric Dynamics: Ocean/atmosphere interactions
Programme: 439;902
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Zorn, S.R.; Drewnick, F.; Schott, M.; Hoffmann, T.; Borrmann, S. (2008). Characterization of the South Atlantic marine boundary layer aerosol using an aerodyne aerosol mass spectrometer. Atmospheric chemistry and physics, 8(16), 4711–4728.
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Priyadarshi, A.; Dominguez, G.; Savarino, J.; Thiemens, M. (2011). Cosmogenic 35S: A unique tracer to Antarctic atmospheric chemistry and the polar vortex. Geophys. Res. Lett., 38(13), L13808.
Abstract: The cosmogenic radionuclide 35S (half life ?87 d) exists in both 35SO2 gas and 35SO42? aerosol phase in the atmosphere. Cosmogenic 35S fulfils a unique niche in that it has an ideal half-life for use as a tracer of atmospheric processes, possesses a gas phase precursor and undergoes gas to particle conversion, providing a chronometer that complements other measurements of radiogenic isotopes of different half lives and chemical properties. Based on radiogenic 35S measurements and concomitant model calculations, we demonstrate that 35S is a unique tracer to understand stratospheric-tropospheric air mass transport dynamics and the atmospheric oxidation capacity on a short time scale. Reported are the first measurements of 35S contained in SO42? aerosols (bulk and size aggregated) at Antarctica. 35SO42? concentrations at Dome C and Dumont D'Urville exhibit summer maxima and winter minima with a secondary winter peak. Higher oxidative capacity of the atmosphere and long range transport of mid latitude air increases 35SO42? activity in summer whereas a lack of air mass mixing coupled with low oxidant concentration in winter significantly decreases 35SO42? activity. A 3% contribution from stratospheric 35SO42? into the free troposphere during stratosphere-troposphere air mass mixing accounts for the secondary winter 35SO42? peak. In the future, this work will be extended to 35S activity measurements of both gas and aerosol phases to further understand gas to particle conversion, vortex dynamics and trace polar stratospheric cloud sedimentation frequency.
Keywords: Antarctica; cosmogenic radionuclide; stratosphere-troposphere mixing; 3307 Atmospheric Processes: Boundary layer processes; 3362 Atmospheric Processes: Stratosphere/troposphere interactions; 3363 Atmospheric Processes: Stratospheric dynamics
Programme: 1011
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Villante, U.; De Lauretis, M.; Francia, P.; Vellante, M.; Piancatelli, A. (2006). Space science reviews, 122(1), 107–117.
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Krinner, G.; Guicherd, B.; Ox, K.; Genthon, C.; Magand, O. (2008). Influence of Oceanic Boundary Conditions in Simulations of Antarctic Climate and Surface Mass Balance Change during the Coming Century. Journal of climate, 21(5), 938–962.
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Merrer, S.; Cara, M.; Rivera, L.; Ritsema, J. (2007). Upper mantle structure beneath continents: New constraints from multi-mode Rayleigh wave data in western North America and southern Africa. Geophysical research letters, 34.
Keywords: Rayleigh waves; upper mantle; 7208 Seismology: Mantle; 7255 Seismology: Surface waves and free oscillations; 7290 Seismology: Computational seismology
Programme: 133;906
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. (2008). Equivalent ionospheric currents for the 5 December 2006 solar flare effect determined from spherical cap harmonic analysis. J. Geophys. Res., 113.
Keywords: solar flare effects; SCHA; magnetic observatories; 1530 Geomagnetism and Paleomagnetism: Rapid time variations; 2409 Ionosphere: Current systems; 2447 Ionosphere: Modeling and forecasting; 7974 Space Weather: Solar effects; 0545 Computational Geophysics: Modeling
Programme: 139
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Spracklen, D.V.; Arnold, S.R.; Sciare, J.; Carslaw, K.S.; Pio, C. (2008). Globally significant oceanic source of organic carbon aerosol. Geophysical research letters, 35.
Keywords: organic carbon; ocean; aerosol; 0305 Atmospheric Composition and Structure: Aerosols and particles; 0315 Atmospheric Composition and Structure: Biosphere/atmosphere interactions; 0312 Atmospheric Composition and Structure: Air/sea constituent fluxes
Programme: 414;415
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