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. (2022). Global reference seismological data sets: multimode surface wave dispersion (Vol. 228).
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. (2022). One Antarctic slug to confuse them all: the underestimated diversity of Doris kerguelenensis (Vol. 36).
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. (2022). Sunlight-driven nitrate loss records Antarctic surface mass balance (Vol. 13).
Abstract: Standard proxies for reconstructing surface mass balance (SMB) in Antarctic ice cores are often inaccurate or coarsely resolved when applied to more complicated environments away from dome summits. Here, we propose an alternative SMB proxy based on photolytic fractionation of nitrogen isotopes in nitrate observed at 114 sites throughout East Antarctica. Applying this proxy approach to nitrate in a shallow core drilled at a moderate SMB site (Aurora Basin North), we reconstruct 700 years of SMB changes that agree well with changes estimated from ice core density and upstream surface topography. For the under-sampled transition zones between dome summits and the coast, we show that this proxy can provide past and present SMB values that reflect the immediate local environment and are derived independently from existing techniques.
Keywords: Cryospheric science Environmental chemistry Palaeoclimate
Programme: 1177
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. (2022). Photolytic modification of seasonal nitrate isotope cycles in East Antarctica (Vol. 22).
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. (2022). Variation Among Species and Populations, and Carry-Over Effects of Winter Exposure on Mercury Accumulation in Small Petrels (Vol. 10).
Abstract: Even in areas as remote as the Southern Ocean, marine organisms are exposed to contaminants that arrive through long-range atmospheric transport, such as mercury (Hg), a highly toxic metal. In previous studies in the Southern Ocean, inter-specific differences in Hg contamination in seabirds was generally related to their distribution and trophic position. However, the Blue Petrel (Halobaena caerulea) was a notable exception among small seabirds, with higher Hg levels than expected. In this study, we compared the Hg contamination of Blue Petrels and Thin-billed Prions (Pachyptila belcheri), which both spend the non-breeding season in polar waters, with that of Antarctic Prions (Pachyptila desolata), which spend the winter in subtropical waters. We collected body feathers and blood samples, representing exposure during different time-frames. Hg concentrations in feathers, which reflect contamination throughout the annual cycle, were related to ?13C values, and varied with ocean basin and species. Blue Petrels from breeding colonies in the southeast Pacific Ocean had much higher feather Hg concentrations than expected after accounting for latitude and their low trophic positions. Both Hg concentrations and ?15N in blood samples of Blue Petrels were much lower at the end than at the start of the breeding period, indicating a marked decline in Hg contamination and trophic positions, and the carry-over of Hg burdens between the wintering and breeding periods. Elevated Hg levels may reflect greater reliance on myctophids or foraging in sea-ice environments. Our study underlines that carry-over of Hg concentrations in prey consumed in winter may determine body Hg burdens well into the breeding season.
Programme: 109
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Philip L. Woodworth. (2022). Advances in the observation and understanding of changes in sea level and tides (Vol. 1516).
Abstract: Climate change, of which sea level change is one component, is seldom out of the news. This paper reviews developments in the measurement and understanding of changes in sea level and tides, focusing on the changes during the past century. The main aim has been to demonstrate how sea level and tidal science are now connected intimately with the fields of climate change and geodesy.
Keywords: extreme sea levels MSL changes ocean circulation variability ocean tides and their changes sea level and geodesy vertical land movements
Programme: 688
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. (2022). Supercooled liquid water clouds observed over Dome C, Antarctica: temperature sensitivity and surface radiation impact.
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Piero Poli, Nikolai M. Shapiro. (2022). (Vol. 49).
Keywords: backprojection seismology source surface waves Tonga volcanology
Programme: 133
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. (2022). Global Carbon Budget 2022 (Vol. 14).
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. (2022).
Abstract: While recent studies highlighted the great mobility of boulder beaches related to the impact of storm waves, numerous researches are still needed to better understand the morphodynamic of coastal boulder accumulations. This paper provides original data about pluri-annual morphological and sedimentological changes, as well as storm-induced geomorphic processes and their impact on the Valahnúkur boulder barrier, in the south-west of Iceland. First described by Etienne & Paris (2010), this massive accumulation of boulders shows numerous evidences of coastal barrier flooding and intense boulder mobility. Between May 2015 and May 2021, a topo-morphological survey was undertaken to analyze and quantify both cross-shore and longshore morphosedimentary processes of the Valahnúkur boulder barrier and surrounding areas. Annual campaigns of UAV (Unmanned Aerial Vehicle) flights were conducted in order to produce a set of Digital Elevation Models (DEMs) and Orthophotographs using Structure-from-Motion photogrammetry. DEMs were compared to deduce the morphological changes. Orthophotographs were analyzed from a deep learning-based method to estimate the changes in the spatial distribution of boulder sizes. Hydrodynamic conditions were reconstructed using wave buoy and tide gauge measurements. Wave runup were calibrated from the analysis of a wave/swash motion data set acquired by video monitoring related to different hydrodynamic conditions. The chronology of extreme water levels has been reconstructed on this high refective beach to estimate the elevation of the wave action during the survey period. From the sediment budget calculation, a significant northward longshore drift of around 1000 m3/a is highlighted on the beachface. The ridge and back-barrier areas were dominated by accretion related to cross-shore boulder transport from the beach. The volume of transported boulders is highly variable according to hydrodynamic conditions. Although the morphogenic impact of winter storms is difficult to assess, the observed morphological changes suggest processes dominated by swash, overtopping and overwash. The boulder size analysis highlights a link between the boulders mass and their movement landward. Video monitoring indicates that the amplitude of the swash is quite similar whether the hydrodynamic conditions are normal or energetic. The high porosity of the barrier appears to be a key factor in the dissipation of wave energy.
Programme: 1216
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