. (2012). Dynamic recycling of gaseous elemental mercury in the boundary layer of the Antarctic Plateau
. Atmos. Chem. Phys., 12(22), 11027–11036.
Abstract: Gaseous elemental mercury (Hg0) was investigated in the troposphere and in the interstitial air extracted from the snow at Dome Concordia station (alt. 3320 m) on the Antarctic Plateau during January 2009. Measurements and modeling studies showed evidence of a very dynamic and daily cycling of Hg0 inside the mixing layer with a range of values from 0.2 ng m−3 up to 2.3 ng m−3. During low solar irradiation periods, fast Hg0 oxidation processes in a confined layer were suspected. Unexpectedly high Hg0 concentrations for such a remote place were measured under higher solar irradiation due to snow photochemistry. We suggest that a daily cycling of reemission/oxidation occurs during summer within the mixing layer at Dome Concordia. Hg0 concentrations showed a negative correlation with ozone mixing ratios, which contrasts with atmospheric mercury depletion events observed during the Arctic spring. Unlike previous Antarctic studies, we think that atmospheric Hg0 removal may not be the result of advection processes. The daily and dramatic Hg0 losses could be a consequence of surface or snow induced oxidation pathways. It remains however unclear whether halogens are involved. The cycling of other oxidants should be investigated together with Hg species in order to clarify the complex reactivity on the Antarctic plateau.
Programme: 1028
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France J L, King M D, Frey M M, Erbland J, Picard G, Preunkert S, MacArthur A, Savarino J, . (2011). Snow optical properties at Dome C (Concordia), Antarctica; implications for snow emissions and snow chemistry of reactive nitrogen. 1680-7316, 11(18), 9787–9801.
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Zhang K, Feichter J, Kazil J, Wan H, Zhuo W, Griffiths A D, Sartorius H, Zahorowski W, Ramonet M, Schmidt M, Yver C, Neubert R E M, Brunke E-G, . (2011). Radon activity in the lower troposphere and its impact on ionization rate: a global estimate using different radon emissions
. Atmos. Chem. Phys., 11(15), 7817–7838.
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. (2011). NDACC/SAOZ UV-visible total ozone measurements: improved retrieval and comparison with correlative ground-based and satellite observations
. Atmos. Chem. Phys., 11(12), 5975–5995.
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Myriokefalitakis S, Tsigaridis K, Mihalopoulos N, Sciare J, Nenes A, Kawamura K, Segers A, Kanakidou M, . (2011). In-cloud oxalate formation in the global troposphere: a 3-D modeling study
. 1680-7316, 11(12), 5761–5782.
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Bousquet P, Ringeval B, Pison I, Dlugokencky E J, Brunke E-G, Carouge C, Chevallier F, Fortems-Cheiney A, Frankenberg C, Hauglustaine D A, Krummel P B, Langenfelds R L, Ramonet M, Schmidt M, Steele L P, Szopa S, Yver C, Viovy N, Ciais P, . (2011). Source attribution of the changes in atmospheric methane for 2006-2008
. 1680-7316, 11(8), 3689–3700.
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. (2011). Atmos. Chem. Phys., 11(1), 363–373.
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. (2010). Estimation of Antarctic ozone loss from ground-based total column measurements
. Atmos. Chem. Phys., 10(14), 6569–6581.
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. (2010). Accelerating growth of HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane) in the atmosphere
. Atmos. Chem. Phys., 10(13), 5903–5910.
Abstract: We report the first measurements of 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), a substitute for ozone depleting compounds, in air samples originating from remote regions of the atmosphere and present evidence for its accelerating growth. Observed mixing ratios ranged from below 0.01 ppt in deep firn air to 0.59 ppt in the current northern mid-latitudinal upper troposphere. Firn air samples collected in Greenland were used to reconstruct a history of atmospheric abundance. Year-on-year increases were deduced, with acceleration in the growth rate from 0.029 ppt per year in 2000 to 0.056 ppt per year in 2007. Upper tropospheric air samples provide evidence for a continuing growth until late 2009. Furthermore we calculated a stratospheric lifetime of 370 years from measurements of air samples collected on board high altitude aircraft and balloons. Emission estimates were determined from the reconstructed atmospheric trend and suggest that current “bottom-up” estimates of global emissions for 2005 are too high by a factor of three.
Programme: 458
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. (2021). Moss-inhabiting diatom communities from Ile Amsterdam (TAAF, southern Indian Ocean) (Vol. 154).
Keywords: Bacillariophyta diatoms ecology Ile Amsterdam mosses southern Indian Ocean sub-Antarctic region
Programme: 136
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